A network of sensors has been set up in Newcastle in order to give policymakers a more accurate picture of the air being breathed by children.
The project is a collaboration with Newcastle University and Newcastle City Council who have installed 22 air pollution sensors outside schools that are located close to major roads.
The data will be collected by Newcastle University’s Urban Observatory, the team will then use this information to help engage the children who are being directly affected and give them a voice as to how their cities should be planned in the future.
The Urban Observatory is the UK’s largest urban experiment collecting data about 60 different urban indicators, everything from energy use, rainfall and flooding to air pollution and traffic flow.
Currently, the Urban Observation has deployed over 3,600 sensors across Newcastle, including AQMesh air quality monitoring systems*, adding 5,000 new observations ever minute.
Eugene Milne, director of public health at Newcastle City Council said: ‘Poor air quality harms everybody’s health, and young people are among those most at risk, so we’re very pleased to be working with the University and young people across the city to address this.’
‘As well as raising awareness of the issues, the project will also aim to encourage more active travel and fewer car journeys, particularly on the school run.’
‘This project will help us to monitor just how much pollution is in the air around schools and enable us to get views of the children who are directly affected on what else could be done to tackle the problem.’
Sean Peacock, who is based in Newcastle University’s Open Lab has said: ‘Children themselves are far from oblivious to the impact that air pollution is having on their health and their futures.’
‘The school climate strike shows that young people are forcing air pollution and the climate crisis to the top of the political agenda.’
‘Urban planners and politicians are often hesitant to work with children, but they shouldn’t be.’
‘We need to embrace their creativity and passion to take radical action on air pollution and climate change. More, now than ever, we need the original ideas that only children can bring.’
All of the data is freely available at Newcastle University’s website: www.urbanobservatory.ac.uk, and is being used by researchers, local authorities, regulators, developers, town planners, businesses and members of the public.
*Original news published in September 2018.
Last month Environmental Defense Fund Europe (EDFE) together with Mayor Sadiq Khan are releasing the second wave of data from Breathe London, an ambitious collaborative project to measure and map air pollution across the capital.
In addition to nitrogen dioxide (NO2) measurements from the network’s 100+ stationary AQMesh pods, the interactive map now includes preliminary data from the Google Street view car drives as well as current and average pollution data for fine particulate matter (PM2.5).
The new data confirms a concerning trend: Air pollution across the capital remains dangerously high. Four out of every five pods, including 90% of schools in the network, are on track to exceed World Health Organisation (WHO) annual guidelines for PM2.5, which is linked to a wide range of adverse health effects. Additionally, preliminary analysis of the mobile data shows NO2 is on average over 50% higher on major through roads than quieter, local roads.
The findings corroborate what EDFE has been saying for some time: Bold action at the national level is needed to cut pollution and create healthy, breathable cities.
Small airborne particles like dust, soot and drops of liquids can create PM. Most PM pollution formed in urban areas is from fossil fuels used in vehicles, construction equipment, heat & power (including wood burning) and commercial cooking.
PM2.5 is made up of tiny particles, which penetrate deeper into the lungs and are linked to lung disease, heart attacks, strokes, asthma and cancer, as well as shorter life spans. This pollution is particularly dangerous for young people – studies show that PM₂.₅ exposure can impair childhood lung development.
Breathe London’s data from the stationary network suggests that over 80% of the pods are likely to surpass WHO long-term guideline for PM2.5. In other words, the annual average concentration of PM2.5 pollution – at the vast majority of measuring sites – is at unsafe levels.
Moreover, although thresholds for PM have been set as general guidelines, there is little evidence to suggest a safe threshold exists below which there are no adverse health effects. Despite the recognition that PM is not safe at any level, it is currently legal in the UK to have pollution levels above what is recommended by the WHO.
Since autumn 2018, two specially-equipped Google Street View cars have been driving London’s streets to measure air pollution. Data from the drives undertaken so far are now visible on the map.
When comparing pollution readings from busy versus quieter streets, preliminary analysis reveals NO2 is on average over 50% higher on busy major through roads than on quieter, local roads*. Like PM, pollution from NO2 is linked to a variety of health impacts, including aggravating asthma and adversely impacting lung function in children.
Amanda Billingsley, Managing Director of Environmental Instruments, the company that manufactured the AQMesh pods, said: “This is a great example of what can be shown by data from a network of stationary small sensor air quality stations, delivering insights that help government and citizens to take effective action to transform pollution exposure levels.
“We have supplied networks of these small monitors in various countries, but it is great to see the potential impact of hyperlocal data – enabling the assessment of air pollution on a street by street basis – in our own capital city.”
The Breathe London data will also be available on the new Air Quality Data Commons (AQDC), an open-access data platform where people can share and use data from low-and medium-cost air quality sensors.
*Comparison assumes error is random. Additional analysis will be conducted after mobile data collection concludes at the end of October 2019.
A version of this article ran on Environmental Defense Fund Europe’s blog on 22 Oct, 2019.
Whilst not the only AQMesh pods still in regular use since the product was commercially launched in 2013, two AQMesh pods are still in use in Spain and demonstrate the long life of this small sensor air quality monitoring system.
Over the last six years, the two pods have been loaned by AQMesh distributor in Spain, Envirodata, to a number of customers for trials and demonstrations, as well as being involved in a range of projects.
In one of these studies the pods were selected to determine how accurately small sensor systems could measure ambient levels of NO2. The collaborative research between the European Life Photoscaling Project, Tecnaire-CM, Greater Madrid Region and Madrid City Council sought to assess the effectiveness of different photocatalytic pavements in reducing levels of NO2 pollution. The AQMesh pods were co-located with two of the region’s larger air quality monitoring stations under traffic and urban background conditions to compare AQMesh readings with reference and calibrate field readings. A paper was published in August 2018 as a result of this study, which determined that with local calibration AQMesh meets the Air Quality Directive’s standards of accuracy at high concentrations of NO2.
These very first AQMesh pods have also been used to determine baseline air quality levels for the La Nucia project in Alicante, in anticipation of the development of a new sports facility. More recently, one pod has been used to evaluate levels of ozone (O3) during the hotter weather in an area within San Agustin, and the other is currently being used by the Madrid Regional Government. Previously, the municipality of Madrid used AQMesh to measure air pollution as part of a traffic reduction scheme, including to reduce speed limits and restrict access to downtown Madrid.
Luis Lombana of Envirodata comments “AQMesh technology is providing us with a unique solution to local air quality monitoring. The combination of compact hardware with advanced data processing algorithms makes AQMesh the best system for mapping city-wide pollution. We have been using these two AQMesh pods for demonstrations and projects since 2013. They have been upgraded by the manufacturer on a few occasions and we are pleased to be able to offer the best AQMesh performance to users with these two old friends. We have no plans to stop using them although we now also sell units with the additional options available, such as PM monitoring.”
The two pods were initially built to measure NO, NO2, O3, CO and SO2, powered by an internal lithium battery, which powers a ‘gas only’ pod for over two years. From 2015 the pod was able to take advantage of developments in the electrochemical sensors, particularly factory sensor characterisation introduced in 2015 (v4.0) and the ozone filter introduced to the NO2 sensor in 2016, which dramatically improved discrimination of O3 and NO2, particularly with the AQMesh proprietary data processing algorithm v4.2. The pods will now be upgraded remotely (a setting change on the AQMesh server), with full traceability, to v5.1 which offers significant improvements in accuracy at higher temperatures.
As well as the original 5-gas suite of sensors, AQMesh can now offer two additional gases – H2S and CO2 – as well as particulate matter (PM1, PM2.5 and PM10), plus noise, wind speed and direction. Other power sources are available with solar being the most popular.
AQMesh pods have been operating in the field since 2013, and so far have been active in over 60 countries in a range of air quality applications. The pods have always been built to a rugged and robust standard, with hundreds of pods installed for years in city centres around the world. The inconspicuous units generally avoid vandalism, damage or malfunction, and in one instance a customer’s pod has still continued to function and transmit data despite being crushed during an accident. They have also proven to withstand extreme weather conditions, continuing to work under several feet of snow during the North American winter and the hot desert climates in the summer months in Australia, South Africa and the Middle East.
A study published in the Journal of the American Medical Association has found that long-term exposure to poor air quality can have the same damaging effect as smoking 20 cigarettes a day, with air pollution shown to be more dangerous than passive smoking.
Many employees are exposed to poor air quality on a regular basis and employers are often unaware of the risks and what they can do to manage them. A new generation of air quality monitoring equipment is now available for measuring the levels of common air pollutants in the immediate areas where staff are working.
Employees working close to areas of high road traffic, particularly with poor air circulation, are especially vulnerable to the effects of pollution. As well as being trapped indoors or brought in through ventilation systems, pollutants can also build up in outdoor spaces, particularly in cities with high buildings, leading to exposure levels which may exceed limits set by the World Health Organisation (WHO).
Diesel fumes were classified as a Class 1 Carcinogen by the WHO in 2017, after it found that people exposed to diesel fumes at work were up to 40% more likely to develop cancer. As such, employers can now be sued if their employees develop cancer later in life as a result of exposure, as reported by The Sunday Times following the reclassification.
The EU limits for nitrogen dioxide (NO2) exposure are 40µg/m3 annually and 200µg/m3 in an hour, no more than 18 times in a year. Many official measurement stations in cities worldwide report NO2 above the annual limit but less is known about local levels of this pollutant. Because NO2 is produced as a direct result of a source, such as traffic exhaust or diesel generators, levels of NO2 regularly exceed the hourly limit when measured in ‘hotspots’, such as busy road junctions, where it is not practical to install a large air quality measurement station, or on a private site.
Previously, air quality has been likened to passive smoking. The International Agency for Research on Cancer (IARC) determined in 2013 that air pollution is more dangerous than passive smoking, and was now the leading cause of cancer. At the time, the IARC’s Kurt Straif told the South China Morning Post “The air we breathe has become polluted with a mixture of cancer-causing substances. We consider this to be the most important environmental carcinogen, more so than passive smoking.”
Measuring ozone (O3) as a part of an air quality monitoring routine is also becoming increasingly important, especially in hotter climates and areas of increased VOC emissions. O3 at ground level is dangerous and is formed by reactions with nitrogen oxides (NOx) and volatile organic compounds (VOCs) from traffic and industrial emissions in the presence of sunlight. This means hotter, sunnier weather can dramatically increase O3 pollution in urban and industrial areas. The WHO currently states the daily limit of O3 levels to be 100μg/m3 over an 8-hour mean and advise that prolonged exposure to high levels of O3 can have severe effects on human health. These include asthma, inflammation of the airways and reduced lung functionality, just as the recent studies comparing air quality to smoking has found.
Senior co-author of the study Dr Joel Kaufman, from the University of Washington, said: “We were surprised to see how strong air pollution’s impact was on the progression of emphysema on lung scans, in the same league as the effects of cigarette smoking, which is by far the best-known cause of emphysema.” The professor of environmental and occupational health sciences and epidemiology added: “We really need to understand what’s causing chronic lung disease, and it appears that air pollution exposures that are common and hard to avoid might be a major contributor.”
Teams responsible for protecting staff from exposure to hazards can now understand exposure in relevant locations by installing compact air quality monitoring equipment designed to continuously measure pollution levels in ambient air.
AQMesh pods are small, wireless units which can be mounted on a lamp post, fencing, wall or a similar mounting point close to where staff are breathing potentially polluted air, both indoors and outdoors. Air quality readings are secure and confidential, accessed online by authorised personnel only.
AQMesh has been used on building sites, industrial sites and at roadside locations worldwide, as well as measuring the air intake into office buildings, in order to monitor the air quality of employees working in these areas on a daily basis and helping to protect them.
Minnesota Pollution Control Agency (MPCA) has been monitoring Minnesota’s air quality for a number of years, and it is generally considered to be good. However, MPCA wanted to understand how air pollution varies across small distances in order to minimise vulnerable communities’ exposure to harmful pollutants.
Following project funding* in 2017, earlier this year MPCA successfully installed AQMesh pods across 44 sites in neighbourhoods around Minneapolis and St. Paul, primarily on lampposts in school parking lots, with at least one pod in each ZIP code.
MPCA gives high priority to community involvement and sharing its air quality data with the public. It has launched an online tool allowing citizens to compare pollution levels at different monitoring sites over a given date range. Monika Vadali, Ph.D, who is leading the project, welcomes feedback on the online tool and the wider project and is looking forward to hearing comments from communities where monitoring is taking place.
Prior to being deployed across Minneapolis and St. Paul, the AQMesh pods were co-located against the FEM station at Blaine airport for a number of months in order for the readings to be compared and validated, and for scaling to be applied if necessary. During the co-location period AQMesh showed high levels of pod-to-pod precision, with an average R2 of 0.94 for NO2, despite extreme weather conditions.
For the next two years, the AQMesh pods will monitor and report data on levels of NO2, O3, NO, SO2, CO, PM2.5 and PM10 in 44 areas of Minneapolis and St. Paul to build up a picture of air quality across the cities. Scientists at MPCA will use the data to determine if there are any significant differences in the concentration of pollutants between ZIP codes, if there are any areas with unusually high levels of pollution, and if technology such as AQMesh is suitable for measuring such small variations in air quality.
The study is similar to the Breathe London project in the UK, where 100 AQMesh pods have been deployed across London to publish a real-time map of the city’s air pollution, which has now also been launched online.
For more information about the MPCA project, please contact Monika on (+1) 651-757-2776.
*This is a legislative funded LCCMR project, with support provided by the Environment and natural resources trust fund (Subd. 07 Air Quality, Climate Change, and Renewable Energy ENRTF # 07b).
Partners and collaborators include the city of Minneapolis, the city of St. Paul, Minnesota Department of Health, Minnesota State University-Mankato, and Xcel Energy.
Detailed information on London’s (UK) air pollution is now being published on breathelondon.org, the website for a new collaborative project to paint a clearer picture of the city’s air quality. The readings are being provided by a network of AQMesh air quality monitoring pods supplied and installed by Air Monitors, part of the ACOEM Group.
The AQMesh pods are stationary – mostly mounted discreetly on lamp posts, but the pod data is being supplemented by measurements from instruments that have been installed by Air Monitors in two Google Street View Cars, as they travel the city’s streets.
Visitors to the Breathe London website will be able to view almost live data (within an hour) on nitrogen dioxide (NO2); one of the urban pollutants of greatest concern.
“This is a major step forward,” says Felicity Sharp, Air Monitors Managing Director. “The availability of highly localised air quality data is critical to the empowerment of citizens so that they can make choices that affect the quality of the air they breathe.
“In the past, air quality data has not been sufficiently local to allow most citizens to change the way they live their lives, but with the benefit of this website they will be able to choose where they want to walk, run, play, go to school or even buy a house.
“The data will also help to raise awareness and thereby encourage citizens to choose more environmentally friendly transport modes, particularly in pollution hotspots.
“Importantly, the data will also help national and local government to assess the effectiveness of air quality improvement measures. So this is great news for London, and we hope that it will be replicated in similar smart city projects around the world.”
Schools near Glasgow have been monitoring air quality as part of a project aiming to reduce the levels of pollution emitted by vehicles as they drop off and collect children. The project is part of a ‘Beat the Street’ initiative that was granted £50,000 from a new £1million fund to increase walking, cycling and sustainable travel in Scotland. The overall aim is to cut Scotland’s carbon emissions, improve air quality, reverse the trend towards sedentary lifestyles and tackle health inequalities.
The Environmental Health department of East Renfrewshire Council supplied and installed the three AQMesh air quality monitoring pods that were utilised in the project. The monitoring activity followed initiatives in eight schools organised with SEPA, in which the children designed their own air quality banners as part of a competition.
The banners were then placed outside the schools which were then monitored for two weeks with an AQMesh pod measuring a variety of parameters including nitrogen dioxide – one of the pollutants of greatest concern. The Council’s Richard Mowat said: “We used one of our own AQMesh pods and rented the other two from Air Monitors. The pods are small and easy to install so we were able to locate them close to the areas most affected by parents’ vehicles.
“The results clearly showed significant peaks in pollution during the drop-off periods and it was pleasing to note how well the project was received. We hope that this work will help educate the children and that they, in turn, will encourage their parents to leave the cars at home and walk whenever possible.”
Anne-Marie Absolom is Head Teacher at one of the participating schools – St Clares Primary School. She said: “Our Junior Road Safety Officers, and all of the school staff, are delighted that we have had the opportunity to install temporary air quality monitors in our car park.
“We have been campaigning throughout the year to improve air quality in and around our school. The children have also been learning about the small changes that they can make – changes that will make a big difference to the quality of the air we breathe.
“The results from the monitors have highlighted the specific times of day at which air pollution is most significant, and the Junior Road Safety Officers are now campaigning at these times. The data gathered has been shared with all children in the school and they are passionate about spreading the word and ensuring that air pollution is reduced.”
As well as supplying the monitoring equipment for the project, Air Monitors also provided sponsorship funds for the school banners, and this was reflected in a stunning night-time time display on the roof of Glasgow’s famous SEC Armadillo, organised by SEPA. A variety of images relating to air quality were projected on to the Armadillo’s roof, highlighting for example Clean Air Day 2019, as well as the Air Monitors logo.
SEPA’s Dr Colin Gillespie said: “It has been great to work again with Air Monitors and the councils, raising awareness in air quality around schools, promoting active changes to reduce pollution and encouraging pupils to think about more sustainable forms of travel.”
Following a successful evaluation phase in 2018, AQMesh small sensor air quality monitoring ‘pods’ have been selected for use in a project to control the ventilation of a road tunnel in the city of Marseille.
Supported by the AtmoSud (AirPACA) local air quality monitoring network, the CETU (Tunnel Studies Centre) and AQMesh distributor Addair, eight AQMesh pods were installed in February 2019, monitoring nitrogen oxides NO and NO2, in an innovative experiment in one of the covered sections of the L2 ring road in Marseille. Called “Boreas project”, after legendary ‘dispersing’ winds, this study aims to use pollution measurements near tunnel entrances to activate in-tunnel fans.
Urban planning is increasingly routing vehicles underground. Although this approach eases air quality and noise at some locations – and overall reduces the level of pollution the population is exposed to – there is a risk that residents living close to the tunnel heads are actually exposed to higher concentrations of pollution as air is expelled from the tunnel.
The L2 ring road in Marseille consists of a succession of covered tunnels over 12Km in dense urban areas. The phased project at the Montolivet South tunnel heads will implement a system for the conditional triggering of in-tunnel fans to evaluate its impact on air quality in the zones adjacent to the nearest residents. This approach was tested in 2018, with micro-sensor readings compared at the AirPACA Kaddouze monitoring station. A first phase analyses the pollution without activation of the ventilation system, then a second phase with ventilation.
The aim is to determine the link between ventilation and dispersion of the pollution at the end of the tunnel and to determine the most effective protocol for activation of the ventilation systems based on real-time air quality levels, inside and outside the tunnel. Automated alerts for high NO2 levels are already in place. The feasibility of this approach will also be reviewed by analysing efficiency in terms of cost and energy consumption. In theory, the use of ventilation could improve the quality of air at the head of the tunnel. However, in some weather conditions this could simply displace the pollution and this forms part of the study – analysing the pollution concentration and dispersion in different meteorological and traffic conditions.
AQMesh has been used in other tunnel monitoring projects, including several in the UK, specifically to study ventilation efficiency in road tunnels where pollution can build up if sufficient air flow is not maintained. During the UK projects, AQMesh pods were also first co-located with a nearby reference station to ensure measurements were directly comparable.
The pods were then deployed at different positions within the tunnels and in ventilation ducts, studying how the concentration of pollution changed when air flows were adjusted in varying traffic scenarios. The pods were able to run for up to six months without any maintenance or calibration, despite the very high pollution levels recorded. The results obtained in these studies enabled optimisation of the ventilation settings and helped to reduce energy consumption whilst maintaining cleaner air for tunnel users and maintenance personnel.
Supporting the aims of Clean Air Day today, 20th June 2019, the Guardian has published a short film demonstrating the changing levels of pollution that children are exposed to as they walk to school in London. The film can be viewed here.
The Guardian Cities team worked closely with their colleagues in multimedia to create a film showing real-time air quality data as a mother takes her young children to school in north London. The video features mother-of-two Natasa pushing a pram and walking her daughter along Marylebone Road, with a Particles Plus instrument attached to the pram and an AQMesh pod on her daughter’s backpack.
The most important air quality parameters are displayed on-screen during the walk, with data including PM10, PM2.5 and nitrogen dioxide (NO2). The film producers have cleverly integrated the European yearly mean limits for these parameters into the display, with readings changing from blue to red when they exceed the limit, (which for PM10 and NO2 was most of the time!).
Documentary producer Anetta Jones, said: “Air quality is a vitally important issue for the health and wellbeing of city dwellers, but the main pollution threats are invisible, so we hope that initiatives such as this will help residents and visitors to better understand the threat that they face.”
The monitoring equipment was supplied by Air Monitors Limited. Their David Green said: “We have recently installed large numbers of AQMesh pods all over London as part of the Breathe London project, and data from these pods will be displayed on the project website. However, video is an enormously popular medium, and it is really exciting to see what can be achieved when the latest technologies in multimedia and air quality monitoring combine.”
Suite à une phase d’évaluation et en raison de sa qualité de mesure, la solution AQMesh a été sélectionnée dans le cadre d’un projet d’asservissement de la ventilation d’un tunnel routier dans la ville de Marseille. Ce projet, porté par le réseau de surveillance de la qualité de l’air local AtmoSud et le CETU (Centre d’Etudes des Tunnels), a vu l’installation de 8 capteurs AQMesh en février 2019 pour le suivi des oxydes d’azotes NO et NO2.
Pour réduire la pollution de l’air aux sorties des tunnels et ainsi limiter l’exposition des riverains, AtmoSud et le CETU (Centre d’Etudes des Tunnels) testent un dispositif innovant basé sur l’activation de la ventilation par des micro-capteurs. Ces derniers, installés début février 2019 par AtmoSud, enregistrent les données sur le terrain pour une phase d’observation, avant de passer à la phase test de déclenchement de la ventilation.
L’implantation des 8 micro-capteurs a été décidée en concertation avec les acteurs
L’adaptation de la ventilation aux niveaux de pollution mesurés en tête de tunnel n’a jamais été mise en œuvre à ce jour et constitue donc une réelle innovation.
Comme pour tout projet innovant, les phases de concertation à chaque étape sont essentielles. Celle du choix de l’emplacement des micro-capteurs l’a été particulièrement.
AtmoSud a donc consulté et les différents acteurs : la DREAL PACA, l’association CAN L2, les services de la mairie de secteur du 11e/12e arrondissement de Marseille, le CETU (Centre d’Etudes des Tunnels), la métropole Aix-Marseille Provence et la Région Sud Provence-Alpes-Côte d’Azur.
Des micro-capteurs soigneusement étalonnés par AtmoSud
Le monoxyde d’azote (NO) et le dioxyde d’azote (NO2), marqueurs du trafic automobile sont les polluants qui vont être mesurés en 8 points. Avant de procéder à leur installation, AtmoSud s’est assuré de la fiabilité des données qui vont être recueillies, en testant les capteurs dans la station de mesure Kaddouz, à proximité de la L2. La phase d’observation va se dérouler sur une période de 3 à 6 mois.
A new network of air pollution monitors has been installed to record emissions from cruise ships docking in Greenwich.
The £80,000 network has been funded by the Port of London Authority (PLA) and installed in partnership with Breathe London and the borough councils covering both Greenwich and Tower Hamlets.
The eight monitoring stations, all located close to the Greenwich Ship Tier landing stage, will capture data around the clock with the raw data available via the websites of both the PLA and Breathe London. A full analysis of the results will be published in early 2020.
The monitors have been supplied by Gloucestershire-based Air Monitors Limited.
Robin Mortimer, PLA chief executive said: ‘The data these monitors collect will give us a comprehensive understanding of the impact that the cruise ships have on air quality when they are in town.
‘It’s crucial to have this information so that we can address the concerns that we know are very strongly held by local residents.’
The monitors are part of the PLA’s Air Quality Strategy, published in May 2018, the first to be produced by a UK port. It includes 25-year targets to halve levels of Nitrogen Oxides and Particular Matter from river-related sources, whilst growing use of the river for carrying both freight and passengers.
Measures already implemented include a programme of retrofitting older vessels with the latest environmentally-friendly technology.
In January, the Department for Transport (DfT) published the first-ever maritime strategy, which details their vision of a zero-emission shipping industry by 2050.
In it, the government said they are considering introducing targets to drive down emissions of GHGs and other air pollutants from UK shipping as ‘the volume of global trade increases.’
They also say they hope to have a group of hydrogen or ammonia powered domestic vessels in operation and at least one major ‘smart port’ in the UK to have all ship-side activity zero emission (including non-road mobile machinery like cranes).
The AQMesh small sensor air quality monitoring system already offers flexibility of monitoring location – through independent power and communications – as well as high data quality and traceability. Now the platform is even more flexible offering up to 20 different data channels. The wide range of sensors, including gases such as NO2, particulate matter (PM1, PM2.5 and PM10) wind and noise can be specified, from a single sensor to a ‘fully loaded’ mini air quality monitoring station.
The small, post-mounted monitoring pod sends raw sensor output to the AQMesh server using the mobile phone network and readings can be accessed by a secure login or API connection. Cloud data management allows settings to be changed online and makes a high level of remote support possible – ideal for monitoring in distant or hard-to-reach locations. Recent developments for 2019 mean that AQMesh offers an increased level of modularity unrivalled by any other small-sensor air quality monitoring system.
The full range of sensors includes gases NO, NO2, O3, CO, SO2, H2S and CO2. Recent work has shown the value of measuring a targeted combination of gases for a given application. For example, H2S and SO2 is popular with the oil and gas industry and measurement of CO2 is valuable as an indicator of combustion to calculate an index. The new wind speed and direction module means local pollution source apportionment can be carried out. All AQMesh pods measure environmental conditions – temperature, atmospheric pressure and RH% – in the same compact unit.
New pods can be built to almost any configuration and modifications can be and are carried out to existing pods returned to the factory. Some modifications are also possible in the field, such as adding extra gas sensors.
Most AQMesh pods are now powered using solar power and the new AQMesh solar module allows the pod and solar pack to be mounted on the same post, using the standard clips supplied, with the power cable simply connected together to start monitoring. The updated solar pack comes as a complete package with a 20W panel, more efficient charging, an additional port for powering two pods, and is now a smart system with a Bluetooth mobile app for checking the output of the panel and running basic diagnostics. Battery and direct (9-24V DC) power options are available.
AQMeshData.net is the AQMesh server which performs secure data processing using carefully developed, unique correction algorithms which compensate for cross-gas effects and environmental factors. AQMesh algorithms are fixed by version and completely traceable, with no use of machine learning or artificial intelligence. Continual development of these algorithms, using datasets from around the world which compare AQMesh readings with co-located reference data, allows AQMesh to demonstrate outstanding, accurate and repeatable performance when co-located against certified reference or equivalent methods, in any part of the world.
AQMesh pods require very little ongoing maintenance, meaning the cost of ownership remains low. Sensor replacement is recommended every 2 years and the demonstrated data stability is very high. AQMesh users also benefit from dedicated, global support from its UK base, where it is designed, developed, manufactured and distributed, as well as a network of trained distributors.
Few people know how clean the air is where they live, work, exercise or where their children go to school. Although air quality can be shown to vary significantly over short distances, air pollution is generally measured using a small number of large, expensive and high quality monitoring stations. The equipment used in these stations is very accurate and complies with measurement standards but they are expensive to buy and maintain, as well as difficult to position because of their size and infrastructure requirements.
With most cities having a single figure number of reference stations at best, many neighbourhoods do not have access to regular and localised air quality information. Historically, the best solution currently is to fill the gaps through modelling, which combines available air quality readings with other information such as emissions inventory.
Demand from communities for better local air quality information is coming at a time when development of smaller, cheaper air quality sensors can provide a solution to the challenge. ‘Small sensor’ air quality systems can provide highly localised pollution measurements, including nitrogen dioxide (NO2) and the key particulate matter measurement, PM2.5, but to provide meaningful measurements on which communities and authorities can make decisions, the information must show traceability to reference measurements.
Many initiatives around the world are aiming to show what can be done, with one of the most ambitious being the Breathe London project in London. 100 small sensor systems are being used, in combination with data from London’s reference network, modelling and readings taken by Google cars modified to carry high quality air monitoring equipment. This project aims to demonstrate how such a ‘hyper-local’ network can be managed, creating a template which can be rolled out to other cities worldwide.
Similarly, 50 AQMesh small sensor air quality monitoring units have been installed to monitor air quality in each of the 50 zip codes in Minneapolis – Saint Paul, USA. “This project is about understanding small-scale differences in air pollution in urban areas in order to minimise exposure to harmful air pollutants, particularly for vulnerable communities. The Assessing Urban Air Quality project will use new air monitoring sensors to broaden our knowledge about air quality in Minneapolis and St. Paul”, commented Monika Vadali, Ph.D, who is leading the project.
AQMesh has also been used to monitor air quality around industrial sites and next to nearby communities which may be affected. As the monitoring units can be positioned with a high degree of flexibility, such as mounting on a lamp post, it is possible to capture data at exactly the point required. With measurements usually every 15 minutes, combined with local wind speed and direction information, it is possible to build up a highly localised picture of likely pollution exposure and identification of pollution sources.
Whilst regulatory authorities are currently defining testing methodologies to help users choose small sensor air quality systems, the best small sensor systems provide a useful and practical tool to supplement existing monitoring networks and are in active use around the world, providing new information about local air quality for a range of applications.
North Americans will be well aware of the particularly harsh weather in the early months of 2019, but AQMesh has taken conditions in its stride. The AQMesh stated operating range of -20°C to + 40°C is backed up by long-term operation across a wide range of climates.
AQMesh pods used by Minnesota Pollution Control Agency (MPCA) to measure pollutant gases and particulate matter, such as NO2 and PM2.5 , installed on streetlights around Minneapolis St. Paul have seen temperatures as low as -25.4°C (-13.7°F) and continue to run smoothly.
Monika Vadali, leading the MPCA project, commented “We are quite impressed with the temperatures we have seen this winter”. However, when asked for a photo of the pods, she said “I can’t get to any of the pods as we have had so much snow and cold that there is 5-6ft of snow around some of the poles, making access difficult.” Temperatures recorded elsewhere have not been so low this year but AQMesh pods have been installed over previous winter in Sweden, Finland, Canada and central Europe, with temperatures regularly dropping below -20°C.
Despite such harsh weather conditions, the AQMesh pods have continued to monitor and communicate data to the AQMesh server, where it is securely accessed by users. The hardware design has been refined to ensure the equipment has the resilience to survive, with minimal maintenance, for years. The initial concept was for the pod to measure pollutant gases, particularly NO2, for two years on a single lithium battery. Although many users now run shorter projects or choose solar or DC power sources, the principle – and challenge – is unchanged.
In addition to its physical design, data processing on the AQMesh server includes carefully developed correction algorithms which compensate for extreme conditions. Remote diagnostics also identify unexpected patterns in sensor output, which may affect confidence in the data, which is then flagged.
At the same time as the AQMesh pods were under several feet of snow in Minnesota, pods in the southern hemisphere have been regularly operating at temperatures in excess of 30°C, hitting 44.7°C in South Africa and 46.2°C in Australia.
AQMesh pods have been deployed long-term (many pods are in their sixth year of deployment around the world) and as temperatures rise across some of the hottest locations where pods are deployed – Kurdistan, Pakistan, Myanmar, Arizona (USA), Ghana – the latest generation of sensors and processing algorithm will continue to provide reliable and traceable air quality measurements in locations where other monitoring equipment cannot readily be deployed.
In the southern regions of the USA, with very hot temperatures and varying levels of humidity, AQMesh pods maintained high precision and accuracy against co-located certified reference equipment, with a correlation R2 of 0.92 for ozone, compared to collated FEM. Many parts of the world where AQMesh operates record relative humidity (RH%) over 90%, often on a regular or sustained basis.
AQMesh also stands up to high winds and extreme rainfall and is now available with an optional wind speed and direction sensor to complement its extensive range of measurable parameters. The meteorological data gathered by this sensor can help distinguish between local and regional sources of pollution.
In an inter-connected world, air quality is increasingly becoming another measurement made available to the public, but how reliable is the data?
Common air pollutants such as NO2 and PM2.5 mix at different rates depending on their source and local weather conditions, particularly wind speed, leaving large local variations in pollution levels. Urban air quality has traditionally been managed by authorities using a combination of large, compliance standard (reference) measurement stations and modelling based on an emissions inventory. Research has shown that increasing the number of measurement points improves the spatial resolution of urban air quality models.
Small-sensor air quality monitoring technology offers the possibility of more local measurements, and its emergence coincides with the appetite from Internet of Things (IoT) developers to map air quality across cities in real-time and communicate this information to the city inhabitants in various ways. This is leading to a growing number of smart city projects using a range of monitoring devices, but understanding the air quality information gathered and sharing it with the public can still be complicated.
Many air quality sensors that are small, cheap and have low power consumption are often very limited by the influence of fluctuating temperatures and cross-gas effects and do not produce good air quality readings. It is therefore beneficial to use a small-sensor air quality monitoring system that incorporates processing, correction and a QA/QC process in order to offer meaningful readings. Environmental authorities, including the US EPA, have developed air quality indices (AQI) and other tools to communicate local air quality to the public. These authorities are looking at how to modify that approach to provide more localised information from small sensor-sensor systems, such as air quality in a neighbourhood – or even a street – rather than a whole section of a city.
AQMesh, a small-sensor air quality monitoring system, is being used in a variety of successful smart city projects which have a range of objectives, but with a common goal of informing the public about the air quality and pollution levels in the local area where they live and work.
‘Breathe London’ was launched in February, with a sophisticated network of air quality monitors to help investigate and improve London’s toxic air. A range of fixed and mobile sensors will be used to build up a real-time, hyperlocal image of London’s air quality. The technology company Air Monitors designed and installed the network of AQMesh air quality monitoring pods, as well as the air quality analysers that were specially adapted to operate inside Google Street View cars.
In Minneapolis, Minnesota Pollution Control Agency (MPCA) has deployed 50 AQMesh pods across 50 zip code areas in order improve understanding of the small-scale differences in air pollution within urban areas.
Similarly in Newcastle, 55 AQMesh pods, supplied and supported by Air Monitors, form part of a network of over 600 sensors managed by the UK’s first Urban Observatory, which aims to provide Newcastle’s citizens with a digital view of how cities work.
These smart cities demonstrate that meaningful and reliable air quality information can be shared with the public when networks are deployed effectively and supported by air quality professionals who understand the capabilities – and limitations – of small-sensor technology and how the local environment affects air quality readings.
AQMesh has been used in a project at the Port of Kiel, Germany, to measure emissions of nitrous oxides (NOx) and fine particulate matter (PM) around its cruise ship terminal.
This year the port attracted 166 visits by 33 different cruise ships, bringing a record breaking 600,000 visitors into the city. Emissions from the cruise ship terminal and its impact on the local air quality has been in discussion for some time, as the city’s references stations indicate that nitrogen dioxide (NO2) levels regularly exceed the World Health Organisation’s annual mean limit of 40μg/m3.
The joint project with Eurofins and Olfasense, who combined AQMesh air quality monitors with the Ortelium dynamic atlas system, measured and studied levels of NO2 and PM at the cruise ship terminal over several months.
AQMesh pods, supplied by its German distributor Envilyse, measured NO, NO2, O3 alongside PM1, PM2.5 and PM10, as well as relative humidity, temperature and atmospheric pressure. After being co-located with passive samplers at the installation site to provide the greatest degree of accuracy, real time sensor data from the AQMesh pods was fed into Ortelium.
The Ortelium atlas allowed measurements from the AQMesh pod to be visualised in real time and, combined with meteorological data feeds, showed how the emission levels changed during arrival, berthing and departure of the cruise ships.
Data analysis from this study concluded the cruise ships could not be attributed to high levels of NO2. This is similar outcome to a study carried out at a UK airport, which concluded that local traffic was in fact more of an issue than the airport activity.
Plumes from shipping are notoriously difficult to detect and analyse from land, but AQMesh now has a carbon dioxide (CO2) sensor which allows a combustion plume to be detected from elevated CO2 levels. Pollutants can then be evaluated in this context.
AQMesh is in use at a variety of harbours and ports around the world including the UK, Italy, Norway, Netherlands, Germany and Vietnam. The pods can now monitor up to 6 gases using the latest generation of sensors, as well as PM1, PM2.5, PM10 and total particle count (TPC) with a light-scattering optical particle counter.
Recent co-location comparison trials against certified reference equipment continue to prove AQMesh performance and reliability for localised air quality monitoring.
Trials in the USA, UK and Western Europe this year have delivered high correlation coefficients (R2 values) for key pollutants such as nitrogen dioxide (NO2), ozone (O3) and fine particulate matter (PM2.5). An R2 value of 0.92 against reference for O3 was achieved in Southern USA over the Summer, as well as an R2 value of 0.94 against reference for NO2 in Northern USA during the cold season.
Co-location trials for AQMesh and field equivalent methods have been taking place globally for several years, with the results published on the AQMesh website, demonstrating how performance and accuracy continues to improve with each new version of the product. A number of independent studies have also been carried out, verifying the AQMesh system’s capability.
AQMesh is a small sensor air quality monitoring system for measuring pollutant gases and particles in ambient air. It is a flexible, quick to install and easy to use air quality monitor that can deliver localised, real-time readings, aiming to improve the spatial resolution, scope and accuracy of gathering air quality data.
Its range of wireless power options includes a recently improved smart solar panel, which is now larger than the previous and has a more efficient charge, allowing for year-round operation for standard gas and particulate AQMesh pods across Western Europe and regions on a similar latitude.
AQMesh pods can now monitor up to 6 gases out of NO, NO2, NOx, O3, CO, SO2, CO2 and H2S using the latest generation of sensors, as well as PM1, PM2.5, PM10 and total particle count (TPC) with a light-scattering optical particle counter. In addition to pollutants, AQMesh can measure noise, relative humidity, pod temperature and atmospheric pressure, all within a single compact unit. Data is completely secure on the AQMesh cloud server, only accessible by a secure login, which allows the user to manage their pods, view customisable graphical data, and download the data for further analysis.
AQMesh is currently in use throughout the world in a variety of air quality monitoring applications and projects, including smart city networks, indoor-outdoor air quality management, employee health and safety, traffic pollution mitigation studies and air quality modelling. Recent case studies show it forming part of a major ‘hyperlocal’ street-by-street monitoring system throughout London (UK), as well as being used in a similar project across 50 zip code areas in Minnesota (USA).
The UK’s first Urban Observatory, led by Newcastle University, has been designed to provide a digital view of how cities work. AQMesh air quality monitoring equipment is being deployed across Newcastle and Gateshead in conjunction with other instruments for monitoring parameters such as air and water quality, noise, weather, energy use, traffic and even tweets.
Forming part of a network of over 600 sensors, the Urban Observatory has already collected over half a billion data points and the information is now starting to shed light on the way different systems interact across the city and provide a baseline against which future cities can be developed and managed.
To date Air Monitors, UK AQMesh distributor, has supplied 55 AQMesh pods and 6 conventional air quality monitoring stations. The conventional stations employ standard reference method instruments to measure key air quality parameters such as Nitrogen Dioxide, Ozone, Carbon Monoxide and Particulates. The AQMesh pods monitor similar parameters, but are smaller, solar-powered, wireless, web-enabled devices that can be quickly and easily located in almost any location.
Commenting on Air Monitors’ involvement in the Urban Observatory project, Managing Director Jim Mills says: “The conventional stations are delivering precise, accurate data, and the AQMesh pods are providing the portability and flexibility to monitor air quality accurately and reliably in the locations of greatest interest.”
“Perhaps the most interesting aspect of this project is its ability to engage with the community, providing detailed local air quality data so that both authorities and citizens can make informed decisions on how to reduce exposure to air pollution. Looking forward, it is clear that work in Newcastle will serve as a model for other cities around the world to follow.”
The National Observatories facility was established in 2017 with the Newcastle Urban Observatory as the founding member, supported by £8.5 million investment from EPSRC (Engineering and Physical Sciences Research Council). The guiding principles are to be technology agnostic and vendor non-exclusive, open by default and transparent by design whilst developing a valued, long-term, sustainable platform. In order for the data to be useful to better understand cities and to facilitate evidence based decision-making across a range of scales and sectors, the data needs to be robust and reliable with known data quality that can be validated.
The AQMesh pods are also being used as part of the ‘Sense My Street’ tool box which enables local communities to deploy sensors and locate them on the streets, collecting evidence to inform or even change their communities.
Phil James, who co-leads the Urban Observatory research, explains: “Cities are complex environments and if we want to develop them sustainably we have to understand how everything interacts.
“By compiling observations and comparing the data, for the first time we are now able to make more informed decisions about designing our cities to work better for people and the environment. Through the Sense my Street project, we are able to give communities the power to gather data relevant to issues that are important to them at a very local scale.”
All of the data is freely available at Newcastle University’s website: www.urbanobservatory.ac.uk, and is being used by researchers, local authorities, regulators, developers, town planners, businesses and members of the public.
AQMesh has been measuring ozone (O3) using small sensors since 2011 and the readings from the latest generation electrochemical sensor, using AQMesh v4.2.3 processing, as compared to co-located certified reference readings, consistently show an R2 of over 0.9 with an accuracy ±10ppb (20µg/m3).
AQMesh pods have been measuring ozone levels around the world and co-location comparison studies show very good performance against reference equipment from the latest sensor and processing version. Ozone levels have been particularly high across Western Europe over this summer but are a regular concern in many parts of the world, including the USA. However, there are huge gaps between O3 monitoring points, to different degrees across the world, depending on monitoring equipment budgets. A lower cost small-sensor monitoring solution can provide valuable data within the areas currently lacking in this air quality information. Data validity is typically demonstrated by comparison with a local reference station, although AQMesh is also widely used where no reference data is available.
O3 at ground level is formed by reactions with nitrogen oxides (NOx) and volatile organic compounds (VOCs) from traffic and industrial emissions in the presence of sunlight. As such, hotter, sunnier weather can dramatically increase O3 pollution.
The World Health Organisation (WHO) currently states the daily limit of O3 levels to be 100μg/m3 over an 8-hour mean and advise that prolonged exposure to high levels of O3 can have severe effects on human health, including causing asthma, inflammation of the airways, reduced lung functionality and lung disease. Measuring O3 as a part of an air quality monitoring routine is therefore becoming increasingly important, especially in hotter climates and areas of increased VOC emissions.
O3 can be complicated to measure due to its high sensitivity to environmental conditions and cross-gas effects. Most small sensors for measuring O3 are either electrochemical or metal oxide, but electrochemical sensors (such as those used in AQMesh) have the advantage of low power requirements and can therefore be installed more flexibly. AQMesh pods are compact, wireless units and are available with a variety of power options, including solar panels, which allow them to be installed exactly where monitoring needs to take place.
During summer 2018 AQMesh has been measuring ozone at hundreds of locations across five continents and co-location comparisons show consistently high levels of accuracy. To quote two of many such studies, in an industrial region of the USA, AQMesh O3 measurements compared to FEM gave an R2 of 0.97, and in a similar comparison study in Western Europe the R2 value for O3 was 0.95. AQMesh pods measuring gases can run continuously for over two years using a battery but other power options are available, including solar. Particulate matter (TPC, PM1, PM2.5, PM10) can also monitored with an AQMesh pod, alongside gases including NO, NO2, O3, CO, SO2, CO2 and H2S, as well as pod temperature, RH% and pressure.
The accuracy of AQMesh readings has been proven through an extensive series of global co-location comparison trials and is the proven, commercially available low-cost air quality monitoring system for both pollutant gases and particulate matter, as well as simultaneously monitoring a range of environmental conditions.
On Sunday 13th May 2018, Cardiff Council organised a car-free day in the city’s central area. As a result of this event air quality monitoring data showed an average 69% drop in nitrogen dioxide (NO2) – one of the pollutants of greatest public health concern. Seeking a better understanding of the relationship between air quality and traffic, Cardiff Council hired three AQMesh air quality monitoring pods from Air Monitors Ltd. The instruments were located on streets impacted by the day’s event, and within two of the Councils Air Quality Management Areas (AQMAs); City Centre & Stephenson Court, Newport Road. The instruments continuously recorded air quality at these locations for 20 days before, during and after the event.
“In comparing the results obtained during the Car Free Day Event with results from the following Sunday (20th May) , the monitor on Duke Street showed an 87% reduction in nitrogen dioxide, the monitor in Westgate Street showed an 84% reduction and the third monitor, which was located less centrally from the main road closures, in Stephenson Court, showed a 36% reduction,” commented a Specialist Services Officer, working for Shared Regulatory Services (SRS) on behalf of Cardiff Council . “Comparing the car-free datasets with those of the following Sunday (20th May); the daily average nitrogen dioxide levels recorded by two of the monitors situated within the City Centre AQMA exceeded the EU yearly average limit (40 µg/m3), but on the car-free day, these two monitors measured daily average figures of just 5 and 8µg/m3 of nitrogen dioxide, providing clear evidence that air pollution in Cardiff city centre is generated by traffic.”
Under the European Ambient Air Quality Directive, Welsh Ministers have a duty to ensure that compliance with air quality objectives defined within the directive is achieved. As outlined in Defra’s UK Action Plan for tackling roadside nitrogen dioxide concentrations, July 2017, modelling has indicated that certain road networks in Cardiff fail to meet EU air quality requirements. Cardiff Council has been directed by Welsh Government to undertake a feasibility study, in order to demonstrate how compliance with the directive and its specified limits will be achieved in the shortest time possible. In order to implement air quality interventions, the Council therefore needs to evaluate the sources of pollution so that appropriate interventions can be assessed to ensure that effective mitigation measures can be implemented. At the same time, it will be necessary to engage with citizens to ensure that they appreciate the importance of tackling air pollution.
Nitrogen dioxide and particulates are the main cause of failures to meet EU air quality limits in cities around the world, and it is well known that traffic, and diesel vehicles in particular, are a major source of these pollutants. The AQMesh pods measure a range of gases including nitrogen dioxide, so by monitoring the effect of removing traffic, the Council will be in a better position to implement improvement measures.
Two automatic air quality monitoring stations are located in Cardiff, and the Council supplements the data from these monitors with a network of non-automatic passive diffusion tubes. However, the Specialist Services Officer from SRS says: “The fixed stations can’t provide street-level monitoring at the most sensitive locations, and the use of diffusion tubes does not provide a detailed understanding of daily trends as they only provide a monthly average figure. However, SRS are aware of the capabilities of the AQMesh pods and are familiar with the accuracy and flexibility that they are able to deliver, which is why they were chosen for the car-free day project.”
In order to assure the quality of the monitoring data, the AQMesh pods that were employed during the project were checked against a reference station and were found to have performed very well. “The pods are small, lightweight and battery-powered which makes them quick and easy to deploy,” the Specialist Services Officer adds. “This is crucial to our work because it gives us the ability to site them on lamp posts so that they measure the air that people are breathing. In addition, they are web-enabled which means that we can monitor air quality in almost real-time; providing a unique insight into the specific events that impact air quality.”
It has been estimated that around 40,000 people in the UK die prematurely as a result of air pollution, mainly in the larger towns and cities. In Wales, the urban areas exceeding EU limits include Cardiff, Swansea, Port Talbot, Newport, Chepstow and Wrexham.
Following completion of the monitoring work in Cardiff, SRS has had requests for the data from a number of organisations, and are keen for the work to be publicised as widely as possible. Highlighting the importance of citizen engagement, the SRS Specialist Services Officer says: “A wide variety of potential measures are available to combat air pollution in Cardiff, but many involve inconvenience for members of the public and cost to the public purse, so we need those affected to be on-board with the measures being taken. We are also hoping that the public will be keen to help, by participating in car-share schemes for example.”
AQMesh is now able to offer CO2 and H2S within its range of gas options for local air pollution monitoring.
The NDIR CO2 sensor, which can be offered within a single AQMesh pod alongside five other gases out of NO, NO2, O3, CO, SO2 or H2S, as well as PM1, PM2.5, PM10, temperature, pressure and humidity, has been developed to deliver a higher performance than those typically used for indoor air quality monitoring. It has been rigorously tested against Picarro reference equipment, resulting in an R2 value of 0.93. Pod-to-pod correlation of over 20 AQMesh pods has shown R2 values of 0.98 and 0.99, and the sensor has a MAE (mean absolute error) of less than 20ppm.
In addition to monitoring deviations from ambient levels of CO2, elevated CO2 levels can indicate that monitoring is taking place in a combustion plume and levels of other gases can be interpreted accordingly. For example, the ratio of CO2 to the other pollutant gases present can indicate whether those gases were emitted by a local or distant source.
An additional electrochemical sensor has been introduced to offer H2S measurements. After integrating the sensor, measurements have been compared to readings from a Honeywell SPM Flex installed at a sewage treatment site with an R2 value of 0.87 over a measurement range of 0-150ppb. Particularly of interest to the oil and gas industry, in association with the SO2 monitoring already available on AQMesh, it can be used to measure emissions from sour gas and residual emissions from flaring operations.
AQMesh can measure up to 6 pollutant gases in various combinations, as well as particulate matter, humidity, atmospheric pressure and noise in one small, compact easy-to-install unit. There is a range of wireless power options, including lithium battery packs and solar panels, with information sent in near real-time to a secure server via cellular GPRS. Data can be accessed by a secure login or can be streamed via an API connection.
AQMesh pods are in use across the globe in a variety of indoor and outdoor air pollution monitoring applications, and are becoming increasingly popular in smart cities and networks. Pod performance has been proven through extensive testing in worldwide co-location comparison trials with reference equipment, which have delivered impressive and reliable correlation results.
London Mayor Sadiq Khan has launched a new, street-by-street monitoring system that will help to improve that capital’s air quality. From July 2018, and operating for a year, London will benefit from what is being described as the world’s most sophisticated air quality monitoring system. A consortium involving academia, an environmental charity, and commercial partners will install a network of 100 multiparameter AQMesh air quality monitors, whilst also operating two Google Street View cars that will map air pollution at an unprecedented level of detail.
Air Monitors Ltd will supply the AQMesh pods and manage data from all the sensor systems, so that air quality can be visualised and mapped in almost real-time. Working closely with the Greater London Authority, the project will be run by a team of air quality experts led by the charity Environmental Defense Fund Europe, in partnership with Air Monitors Ltd., Google Earth Outreach, Cambridge Environmental Research Consultants, University of Cambridge, National Physical Laboratory, King’s College London and the Environmental Defense Fund team in the United States.
Air Monitors Managing Director Jim Mills says: “It is difficult to underestimate the importance of this project – traditional monitoring networks provide essential information to check compliance against air quality standards, but this network will be ‘hyperlocal’ by which we mean that it will deliver street-level air quality data, which will be of tremendous interest to the public and also enable the effective assessment of air quality interventions.
“The Google Street View cars will take readings every 30 meters, helping us to find pollution hot-spots, so that AQMesh pods can be positioned in these locations. However, the pods are wireless and independently powered, so they can also be quickly and easily fixed to lamp posts in other sensitive locations such as schools.”
In addition to nitrogen dioxide and particulates, which are the pollutants of greatest concern, the pods will also measure ozone, nitric oxide, carbon dioxide, temperature, humidity and pressure. Data will sent, near real-time, to Air Monitors’ cloud-based data management system, which can be accessed by PC, tablet or smartphone by authorised partners, using an assigned login.
The monitoring data will provide baseline air quality data that will be essential in the assessment of mitigation measures, particularly in London’s expanding ultra-low emission zone. For example, on 20th June 2018, Sadiq Khan, announced the creation of the largest double-decker electric bus fleet in Europe, and the new monitoring network will enable the assessment of this initiative’s impact on air quality.
“This project will provide a step change in data collection and analysis that will enable London to evaluate the impact of both air quality and climate change policies and develop responsive interventions,” said Executive Director for Environmental Defense Fund Europe, Baroness Bryony Worthington. “A clear output of the project will be a revolutionary air monitoring model and intervention approach that can be replicated cost-effectively across other UK cities and globally, with a focus on C40 cities.”
Mark Watts, C40, Executive Director said: “Almost every major city in the world is dealing with the threat of toxic air pollution, which is taking an incredible toll on the health of citizens, public finances, quality of life and contributing to climate change. London is already a world leader in responding to this global threat and with this initiative it will set a new global standard for how street level air quality monitoring can inform strategic policy making. Cities across the C40 network and around the world will be watching closely to understand how this monitoring can deliver cleaner air for their citizens.”
About Environmental Defense Fund
Environmental Defense Fund Europe is a registered charity (1164661) in England and Wales. A recently established affiliate of leading international non-profit Environmental Defense Fund (EDF), the organisation links science, economics, law, and innovative private-sector partnerships to create transformational solutions to the most serious environmental problems. Connect with us at edf.org/europe, on Twitter and on our EDF Voices, EDF+Business and Energy Exchange blogs.
About Air Monitors Limited
Air Monitors is the UK’s leading air quality monitoring company, supplying and supporting instrumentation to central government, local authorities, research and industry. Air Monitors supplies and supports AQMesh in the UK and will also provide and maintain the equipment within the Google Street View cars in the project.
AQMesh is a fully developed and independently evaluated small sensor outdoor air quality monitoring system, manufactured in the UK by Environmental Instruments Ltd. and in use worldwide since 2012.
About Cambridge Environmental Research Consultants
Cambridge Environmental Research Consultants (CERC) are world leading developers of air quality modelling software. Their renowned ADMS-Urban model will be used together with the sensor data to generate hyper-local air quality mapping both for nowcasts and forecasts, and for policy studies.
About Google Earth Outreach
Google Earth Outreach is a program from Google designed specifically to help non-profit and public benefit organisations around the world leverage the power of Google Maps and Cloud technology to help address the world’s most pressing social and environmental problems.
About the National Physical Laboratory (NPL)
NPL is the UK’s National Measurement Institute, providing the measurement capability that underpins the UK’s prosperity and quality of life. Every day our science, engineering and technology makes a difference to some of the biggest national and international challenges, including addressing air quality issues. http://www.npl.co.uk/about/what-is-npl/
About University of Cambridge Department of Chemistry
The University of Cambridge Department of Chemistry is a world leading research and teaching institution. At Cambridge, the Centre for Atmospheric Science has played a primary role in the development of low-cost sensors for air quality monitoring and in the development of techniques for analysing and interpreting measurements from sensor networks.
About the C40 Cities Climate Leadership Group
Around the world, C40 Cities connects 96 of the world’s greatest cities to take bold climate action, leading the way towards a healthier and more sustainable future. Representing 700+ million citizens and one quarter of the global economy, mayors of the C40 cities are committed to delivering on the most ambitious goals of the Paris Agreement at the local level, as well as to cleaning the air we breathe. The current chair of C40 is Mayor of Paris Anne Hidalgo; and three-term Mayor of New York City Michael R. Bloomberg serves as President of the Board. C40’s work is made possible by our three strategic funders: Bloomberg Philanthropies, Children’s Investment Fund Foundation (CIFF), and Realdania.
Extensive research has shown that indoor air quality is often worse than outdoors. Closed system buildings trap harmful particles inside, and external air intakes can bring in more polluted air from outside.
Whilst many heating, ventilation and air conditioning systems (HVAC) use particle filtering, managed through air exchanges, they can often worsen levels of polluting gases, such as NO2 – now classified by the World Health Organisation as a Class 1 carcinogen. Natural ventilation systems have no particulate filtration at all, and buildings are also frequently completely shut up all night with no ventilation running, trapping the pollution that has built up over the day.
Unlike outdoor air quality (which the government is responsible for), indoor air quality is the responsibility of the building owner or manager, and with research proving that poor air quality has a significant impact on human health, air pollution should be a key factor of employee health & safety.
Future Decisions has teamed up with AQMesh and UK distributor, Air Monitors Ltd, to supply pollution mitigation to improve indoor air quality. Future Decisions has developed patented smart management strategies that aim to reduce internal air pollution by 30% – this is usually enough to bring the air quality within UK & EU regulatory levels, and often within the World Health Organisation levels.
AQMesh measures NO, NO2, O3, NOx, CO, CO2, SO2, PM1, PM2.5, PM10, temperature, pressure and relative humidity in a small pod which can be mounted both indoors and outdoors on a wall or post. Batteries, solar power and DC power options give flexibility of mounting anywhere. AQMesh was designed to offer an easy-to-use air quality monitoring system that can deliver localised real-time readings, improving the accuracy and scope of gathering air quality data in order to support initiatives to reduce air pollution and its risk to human health.
Minnesota Pollution Control Agency (MPCA) has purchased fifty AQMesh pods to measure key air pollution gases and particulate matter across fifty different zip code areas. These small sensor air quality monitoring systems measure NO, NO2, O3, CO, SO2, PM1, PM2.5, PM10, temperature, pressure and relative humidity and will be installed – one per zip code – around the twin cities of Minneapolis and Saint Paul. The two-year project, funded by a legislative grant*, is to supplement the air quality information available to the public.
Deployment across the 50 zip codes has been mapped out after several public meetings involving the local community to determine where residents felt monitoring was needed. The small yellow triangles represent the points which local residents asked for sensors to be installed, and the green dots indicate the planned installation site based on the infrastructure available for mounting the AQMesh pods.
“This project is about understanding small-scale differences in air pollution in urban areas in order to minimise exposure to harmful air pollutants, particularly for vulnerable communities. The Assessing Urban Air Quality project will use new air monitoring sensors to broaden our knowledge about air quality in Minneapolis and St. Paul”, commented Monika Vadali, Ph.D, who is leading the project.
The pods are currently installed at the Blaine airport Federal Equivalent Method (FEM) station so that AQMesh readings can be compared to and validated against air quality readings taken using this US approved methodology, with scaling then applied if necessary. The MPCA team intends to install the pods in each zip code during the next month or two. The pods will be powered using a bespoke solar power pack: 30W panels have been specified for such a northern location, compared to the 15W normally required to supply the low-power AQMesh platform. The pods can be battery powered but 12V DC supply was specified, given the 2-year project timescale.
The pods were installed in November 2017 and have achieved 100% uptime to date, including during severe weather conditions, with temperatures below -25°C / -15°F and heavy snow. Initial comparisons against co-located pods show a high level of pod-to-pod precision, with an average R2 of 0.94 for NO2, 0.92 for O3 and 0.93 for PM2.5.
The 50 pods have been compared to the FEM station in two batches of 25, and the first batch of comparisons show an average co-location comparison correlation R2 of 0.74 for O3 and NO2, 0.86 for PM2.5, 0.93 for PM10 and 0.82 for NO. The reference CO showed a baseline shift part way through the comparison period, so that comparison is being reviewed. The SO2 R2 was depressed by a max FEM reading of 2.5ppb, with low FEM resolution, but AQMesh readings were within +/- 2ppb of reference.
The MPCA team is setting up an API connection to the AQMesh server, allowing air quality data to be streamed, near real-time, to the MPCA server, from which it can be published.
AQMesh is in use at various locations in the USA, as well as 35 other countries. The pods deployed in Minnesota are the current production version (v4.2.3).
More information about the MPCA project is available at https://www.pca.state.mn.us/air/assessing-urban-air-quality-project.
* The project is funded by a legislative grant: Environment and Natural Resources Trust Fund (ENRTF) M.L. 2017, Chp.96, Sec. 2. Subd.07b
The team at AQMesh continue to receive many enquiries from smart city initiatives and are concerned that integrators risk undermining entire projects by distributing meaningless or misleading air quality information.
“Many of the people I speak to are used to dealing with sensors that are easy to ‘plug and play’ and expect to be able to do the same with air quality sensors. This is not helped by the fact that most air quality sensors, sensor systems or ‘nodes’, on the face of it, offer very similar specifications”, comments Amanda Billingsley, AQMesh Director. “Quite understandably, IoT professionals do not generally have a background in air quality measurement and are not aware how notoriously difficult it is to get good air quality readings from small sensors, particularly nitrogen dioxide which is known to be so harmful and a key component of diesel fumes – now classified by WHO as a carcinogen.”
Most of the air quality sensors that are small, cheap and low enough energy for IoT applications also have limitations, such as the influence of rapidly changing temperature and cross-gas effects, and a significant level of experience is required to apply the corrections needed to get useable real-time air quality data. At this stage there are two options: one is to try to deal with the challenge in the measurement hardware, such as managing the conditions in which the sensors operate, but this often leads to large and expensive hardware. The other option is smart cloud-based correction algorithms.
Because of the length of time it has been in the field and the huge variation in environments in which AQMesh has been used and validated / corrected, AQMesh is acknowledged through independent studies to be further down this route than any other small sensor system. Even smart city projects which aim to deliver ‘high level’ air quality information, such as ‘the air quality is better here than there’ or some traffic light system, need to be confident that such conclusions are correct if they are not to be challenged by local authorities and stakeholders.
AQMesh is being used in various smart city and IoT projects around the world. In a collaborative smart city project in Cambridge, UK, AQMesh data was analysed by Professor Rod Jones from the University of Cambridge. “Because we know that all the pods read the same and because we have a comparison between one pod and a reference instrument we can say that all pods are working equivalently across the city. What we are seeing is correspondences in excess of 0.7, 0.8, against reference – and that is very good for straight out of the box”, commented Professor Jones.” The study shows that AQMesh can help cities manage air quality, for example by distinguishing between locally and regionally generated pollution, as well as publishing air quality information for the public.
AQMesh measures NO, NO2, O3, NOx, CO, SO2, PM1, PM2.5, PM10, temperature, pressure and relative humidity in a small pod which can be mounted in a post, on a wall, outdoor or indoor. Batteries, solar power or 12V DC power options give flexibility of mounting to capture air quality data from any point in a smart city or elsewhere.
Westgate Oxford is a brand new £440m shopping centre comprising of retail outlets, restaurants and a cinema, and was developed as a replacement to the old shopping centre that was demolished in 2016. Having recently opened in October 2017, it estimates it will attract 15m visitors every year.
The AQMesh pods were purchased by the Westgate developer under a Section 106 agreement to monitor levels of NO, NO2 and O3. Oxford City Council’s Air Quality officer, Pedro Abreu, has been using them to supplement information available from other sources. Because the pods are battery-powered they can be mounted at exactly the point in centre where monitoring is required, and easily moved to a new monitoring location when necessary. Pedro Abreu carried out co-location comparisons with a reference station and is very satisfied with the correlations he has seen with the AQMesh pods he is using.
His comments echo those of Professor Rod Jones from the University of Cambridge, who led a project using AQMesh pods across Cambridge to demonstrate how air quality varies across the city. “Because we know that all the pods read the same and because we have a comparison between one pod and a reference instrument, we can say that all pods are working equivalently across the city. What we are seeing is correspondences in excess of 0.7, 0.8, against reference – and that is very good for something straight out of the box”, commented Professor Jones.
A new paper published by the American Chemical Society (ACS Sensors) reviews the use of amperometric electrochemical gas sensors for monitoring inorganic gases that affect urban air quality. Written by John Saffell and Ronan Baron of Alphasense, the paper gives a full explanation of how the sensors work, how they have developed and a review of how they have been used. Key relevant studies are summarised as well as major studies using the sensors.
The paper mentions AQMesh as ‘the first provider of integrated air quality networks’ using the Alphasense sensors, and also refers to AQMesh correction algorithms (the authors consider data correction necessary) and the comparison field trials published regularly on the AQMesh website. University of Cambridge, Citi-Sense and IDAD projects, which used AQMesh, are mentioned: of the range of sensor systems submitted for the 2 week field comparisons trial in Aveiro, ‘The AQMesh unit achieved the highest correlation coefficient and the lowest mean absolute errors: R2 was 0.70 for O3, 0.89 for NO2, 0.86 for CO and 0.80 for NO. Other sensor boxes were unable to provide the same degree of correlation, possibly because of the lack of data correction for temperature variations.’
In October, the AQMesh distributor in Germany – Envilyse – was personally invited to Austria to take part in an annual conference for the ambient air community. During the two-day event, members from the Austrian monitoring networks delivered lectures and shared information on current ambient air monitoring issues.
Envilyse currently run a number of AQMesh projects throughout Germany and Austria and were promoting AQMesh on their stand during the event.
Two AQMesh pods were used to measure NO, NO2, O3 and CO during May and June 2017 at Upplands Motor Stockholm AB car dealership in Sweden, located on the highway between Stockholm city centre and Arlanda airport. The objective was to measure the air quality outside and inside the combined showroom and workshop, demonstrating the importance of measuring common traffic-related pollutants indoors as well as outdoors. The project was also to assess the suitability of AQMesh for this application, including ease of installation and relocation.
The car dealer is situated immediately next to a major highway and the premises are used for car servicing and repairs as well as sales. The air in the building is managed using a standard heating and ventilation management system which ensures adequate air exchange when the building is in operation.
One of the pods was moved indoors between 9th May and 9th June – this can be clearly seen in the temperature plot comparison for both pods during May and June (the pod moved indoors is shown by the blue line on the plot below). The indoor unit showed significantly elevated levels of NO and CO indoors during that time, compared to the unit which remained outside. Although the NO levels indoors largely tracked the outdoor levels, they were consistently around 40-50ppb higher. This may be because the ventilation system is not adequately exchanging air indoors, as the ventilation system in the building is activated at 7am and stops at 6pm when the dealer closes for the day.
The AQMesh pods were then mounted together outdoors again at the end of the indoor trial, clearly showing that the units continued to agree with each other when measuring in the same space, with a pod-to-pod R2 of over 0.8.
Whilst many heating, ventilation and air conditioning systems (HVAC) focus on CO2 measurement – managed through air exchanges – and particle filtration, they can actually make levels of common pollution gases, such as NO2, worse. Air intakes may be situated where outdoor air quality is poor, such as in a car park or near a road, air intake is often during busy traffic periods, and HVAC systems may be switched off just as outdoor air is clearing, trapping pollution indoors overnight.
With diesel exhaust fumes – which include NO2 – now classified as a class 1 carcinogen by the World Health Organisation, forward-thinking companies, such as Upplands Motor, are becoming the first to understand these issues and are focusing on management of indoor air to ensure that the air quality for their workers is at least better than outdoors. AQMesh can also quantify exposure of employees to NO2 and other pollutants when working outdoors, such as on civil engineering sites, directing traffic, or driving a bus.
AQMesh was designed to offer an easy-to-use air quality monitoring system that can deliver localised real-time readings, improving the accuracy and scope of gathering air quality data in order to support initiatives to reduce air pollution and its risk to human health. It continues to be proven as a reliable and accurate instrument for monitoring air quality, whether indoors or outdoors.
The Parliamentary Review is an annual publication which is released to coincide with the beginning of the new Parliamentary year, acting as a guide to cross-sector best practice for the UK’s leading policy makers. The AQMesh team was invited to join Members of Parliament and celebrities at a Gala launch event in the Members’ dining room at the Houses of Parliament at Westminster, London.
AQMesh features alongside a small number of other outstanding organisations in the publication, looking back on the year in industry and how leaders have overcome challenges in the current economic and political climate.
The AQMesh feature describes how this new ‘small sensor’ system is revolutionising air quality monitoring, allowing pollution to be understood at a truly local level for the first time. “This means policy makers have the best possible change of taking informed steps to protect the public from air pollution,” comments Amanda Billingsley, Director at Environmental Instruments Ltd., the Stratford-upon-Avon based manufacturer. “AQMesh is a global sector leader and we are delighted to have our achievements recognised in this way.”
AQMesh is also working with UK, European and US authorities to help shape the certification process and develop suitable methods for assessing small sensor air quality systems. As the article explains, “because AQMesh has led the field for several years, it will help to shape the certification process by showing what is possible with such equipment”.
Read the full review here, with AQMesh featured from page 55.
Cleves School in Weybridge, Surrey (UK) has used AQMesh to measure pollution at the primary school’s entrance. The project, led by Dr. Edward Salter over the school’s summer term, aimed to understand exposure of the children (aged 7-11) to dangerous pollutant gases, with particular interest in the levels of nitrogen dioxide (NO2) and ozone (O3).
Initial findings showed that levels of O3 exceeded 100µg/m3 on several occasions during the high temperatures in June, and a daily pattern of gas peaks coinciding with school pick-up and drop-off was noticeable for nitric oxide (NO). NO2 levels increased later in the day both as a result of oxidation of school-related NO and from general traffic locally, with elevated levels of NO2 up to the end of the evening commute, probably from traffic on local and major roads nearby. The monitoring also showed 15-30 minute spikes from diesel buses or cars parked very early in the morning or late at night with their engines running constantly, as well as from local events at the weekend, when the air quality is otherwise generally seen to improve considerably.
The project set out to determine whether pollution peaked at school drop-off and pick-up times in order to encourage cleaner methods of getting to and from school, after a transport assessment for the expansion of the school highlighted that traffic peaked around 8.30am and 3.15pm for approximately 30 minutes. The school is reviewing findings and will consider a number of mitigation measures, including timing exercise sessions for periods of lower pollution.
AQMesh monitors were installed to monitor NO, NO2, NOx and O3 at each school gate during these peak traffic periods. “There is clearly an effect between pollution levels and travelling to school by car. If I were to do this again I would ask to monitor to additional gases, VOCs and particulates”, said Dr. Edward Salter. AQMesh can currently measure PM1, PM2.5, PM10, CO and SO2, as well as the three gases in this study, and options for H2S and CO2 are due to be released by the end of 2017.
“The AQMesh pods were simple enough for the school to handle, which is not true of all such equipment”, added Dr. Salter.
AQMesh was designed to offer a robust and easy-to-use air quality monitoring system that can deliver localised real-time readings, improving the accuracy and scope of gathering air quality data in order to support initiatives to reduce air pollution and its risk to human health.
AQMesh has been used in various education-related projects globally. At the simplest level AQMesh offers an accessible way for schoolchildren to engage with local air quality issues. Used in conjunction with wind speed and direction information, local real-time data from AQMesh can be used to distinguish between local sources of pollution, which can be managed, and more distant sources of pollution which require a different approach. AQMesh data can also be used to improve the accuracy of air quality models at the local level.
At the IAPSC in May 2017, Professor Rod Jones of the University of Cambridge presented his case study on large scale deployment of sensors, which included showing how AQMesh can be used to discriminate between local sources of pollution and regional sources of pollution.
The study also found how modelling captures the magnitude of an event, but not the timing, and concluded that AQMesh captures spatial gradients very well.
AQMesh is currently in use in Nicaragua, monitoring air quality in communities living near Masaya volcano. The six AQMesh pods have been used to show variations in volcanogenic SO2 and PM levels at different times and at different locations across the area.
The pods, which have independent power and communications so they can be mounted where required, were installed in March 2017 as part of a research project funded by the Global Challenges Research Fund: Unseen but not unfelt: resilience to persistent volcanic emissions (UNRESP). The project is led by the University of Leeds and is a multi-partner collaboration of several universities in the UK and Nicaragua, as well as Nicaragua’s natural hazards observatory INETER and the Icelandic Met Office.
The Global Challenges Research Fund supports projects focusing on challenges faced by developing countries, aiming to build resilience to natural and anthropogenic hazards. The aim of UNRESP project is to devise an early warning system for dangerously high levels of air pollution, specifically SO2 and particulate matter. As this is a 12-month foundation phase project, the data are not currently being made public but will be put in the hands of local authorities and other stakeholders when the warning system is refined. AQMesh readings are being compared to predictions from a pollution dispersion model, CALPUFF, which requires relatively little computing power. The CALPUFF model has been successfully used for air pollution forecasting at other volcanic sites, such as a recent eruption in Iceland which did not produce ash but emitted twice as much SO2 as all European Union countries combined and caused repeated air pollution in Iceland for 6 months.
“Air pollution is a chronic and serious hazard affecting many developing countries, but there is generally very limited capability to monitor and mitigate it. AQMesh provided us with an opportunity to install the first AQ monitoring system in Nicaragua – the pods are very cost-effective which is of utmost importance for the local setting, yet they provide data that are of high quality. Real-time data on the ground is vital for quantifying and understanding the duration, peak concentration and frequency of high air pollution episodes, which are factors that directly impact human health”, commented Dr. Evgenia Ilyinskaya who is leading the project. The UNRESP team started by hiring five pods for three months via UK distributor, Air Monitors Ltd. as well as purchasing one AQMesh pod for long-term observations. The pod rental has been extended for another three months and the practicality of long-term use of this sort of equipment is being evaluated, including the use of rechargeable batteries or solar power. The team is working closely with local communities and such stakeholders taking custody of the equipment intended to protect their own community mitigates against some risks, such as theft or damage.
Although there is no reference station at the site, diffusion tubes have been used to take measurements which can be compared to the 15-minute average, real-time readings from AQMesh. Whilst EU air quality standards focus on the short-term high concentrations typical of SO2 from an industrial source the UNRESP team is trying to understand the impact of long-term elevated SO2 on the population. Having SO2 measurements with high time and spatial resolution is critical for this and the plan is to potentially create an alert for accumulated concentration of pollutants.
The draft proposal for a follow-on project at the site states the collaboration with AQMesh identified ways of improving the equipment for monitoring volcanogenic pollution, which tends to be much more corrosive than ‘typical’ urban pollution. Dr. Evgenia Ilyinskaya commented, “the AQMesh equipment is extremely cost-effective while providing data quality comparable with EU-certified monitoring. One AQMET station was purchased during the UNRESP foundation phase and it will remain in Nicaragua to form part of the permanent AQ network.”
Recent co-location comparison trials using the latest AQMesh processing (v4.2.3) have further proven AQMesh performance with impressive R2 values in excess of O.8 and 0.9 for NO2 in Benelux, Slovakia and Spain.
Particulate matter (PM2.5) was also monitored throughout the Slovakia trial and delivered an R2 value of 0.98.
Correlation values for NO continue to be high throughout all AQMesh co-location trials, with results exceeding 0.9 in nearly all cases.
For more information on co-location trials and performance please contact us.
Leading small sensor air quality monitor, AQMesh, has recently been shown to work alongside passive samplers and air quality models, as well as complementing reference station networks. A recent study shows AQMesh calibration against diffusion tubes and two 2017 conferences have highlighted the potential of such systems used in an air quality network.
At the Dispersion Modellers User Group Meeting (DMUG, London, April 2017), CERC showed that the model optimisation of 7-day average NO2 concentrations using AQMesh readings as well as reference data affects concentration contours, giving a general reduction, but increase in some areas. The study shows the potential to achieve a higher level of local air quality accuracy from this combined approach.
The CERC study uses near real-time NO2 data from 20 AQMesh pods and 5 reference stations across Cambridge, UK over three months. The presentation acknowledged the potential from large networks of low cost sensors installed across a city: accuracy and reliability is generally lower than reference monitors, but larger spatial coverage is possible. The study addressed how these sensor data can best be used in modelling. See the full presentation here.
It is important to distinguish between small air quality sensors and sensor systems. The best sensor systems offer optimisation of sensor output through quality control, platform design and sensor output processing and correction for cross-gas effects and environmental effects. Teams which want to invest in similar air quality studies or city-wide monitoring projects can get a head start by using AQMesh – the most developed such system. See the Cambridge case study of latest AQMesh performance.
International air quality experts meeting at RIVM in the Netherlands in February reviewed a range of studies using small sensor systems to measure air pollution, particularly NO2 and particulate matter. Whilst highlighting the need for good characterisation of sensors and the pace of development of this new technology, discussions focused on how to make the best use of ‘low cost’ sensors.
Two speakers highlighted the ways in which a small sensor system can be characterised. The best method is by regularly co-locating with a reference station and comparing readings; another method is similar but one sensor system is co-located against reference and then moved around the other units to allow comparison. Other options include comparison with passive samplers or by comparing co-located sensor systems against each other.
AQMesh NO2, PM10 and PM2.5 readings from the Citi-Sense project (2015-16, AQMesh v3.5) – a superceded version of AQMesh without standard sensor quality control or characterisation – were compared with maps of reference data using data fusion and showed encouraging results. An even earlier AQMesh project in Asia (2014, AQMesh v3.0) compared source apportionment plots generated using reference data to those from co-located AQMesh pods and the conclusions to be drawn about pollution sources were the same.
AQMesh continues to build on years of global studies and continued development, offering the most ‘project-ready’ small sensor system which can be used in an air quality network – including reference stations, passive samplers and modelling – to proven effect. See more information about AQMesh performance and versions.
The AQMesh team has carried out a test which shows that calibration (scaling) of AQMesh against one, or ideally several, diffusion tubes, is a viable option when no local reference station is available.
When three AQMesh pods and four NO2 diffusion tubes were co-located against a reference station, the diffusion tube readings were so consistent with the reference average reading for the period that the diffusion tube average could be used to apply a slope correction to AQMesh data.
By careful management of the co-location phasing it is possible to record sufficient data points to also correct any offset.
Passive samplers for key pollutants such as NO2 are widely available and are often used to reach areas not covered by more expensive and bulky reference stations. Small sensor systems or so-called ‘low cost’ sensor systems can help to fill the data gap between reference real-time readings, passive sampling single average measurements and model output. Calibration of small sensors systems, such as AQMesh, against certified and validated measurements provides a trail of data validity.
On 9th April The Sunday Times reported that employers have been told they are legally obliged to protect their staff from diesel fumes — and could be sued if workers develop cancer later in life. Read the full article here.
Employers who want to assess risk to employees can use AQMesh to take round-the-clock readings of a range of measurements including key pollutants NO2 and PM2.5. The small, battery-powered devices transmit data using the mobile phone network and data can be accessed using a secure online login.
The Sunday Times article is based on a reclassification of diesel fumes as a “grade 1 carcinogen” by the International Agency for Research on Cancer, part of the World Health Organisation, after it found that people exposed to diesel fumes at work were up to 40% more likely to develop cancer.
The Institute of Occupational Safety and Health (IOSH) and Health and Safety Executive (HSE) have issued the warnings and as many as 500,000 UK jobs may be affected. Clearly it is not just UK workers who are affected by diesel fumes in the workplace. Employees with jobs that could involve high exposure to diesel fumes are any who spend much of their time on or close to busy roads or railways, or near running diesel engines or generators.
Studies with AQMesh have shown high exposure to NO2 and particulate matter inside vehicles such as taxis and also inside office buildings. Although buildings often have active air management to reduce CO2 levels, air intakes can be positioned such that they draw in air from a highly polluted area. Particles may be filtered out but without knowing how levels of the invisible, odourless pollutant NO2 are potentially building up, it is very difficult to manage indoor air quality. Read more…
Employers may be required to take action, including practical advice for employees to minimise exposure. However, exposure can vary dramatically depending on location – inside or outside a vehicle or building – time of day, day of the week, etc. For employers to understand the risk presented to employees and to take appropriate action, it is straightforward to assess air quality very close to the point at which employees are inhaling air.
The best quality data about air pollution comes from reference stations, using validated equipment. However, such stations are large, immobile and require power and communications infrastructure. AQMesh can be located in a fixed position to monitor a workplace on an ongoing basis, such as inside a facility, next to a professional driver or on a fence next to a construction team. AQMesh can be calibrated against reference instruments to establish reading validity. Further advice about management of AQMesh data is available from www.airmonitors.co.uk.
Smart city projects pursue the vision of instrumenting a city with a large number of measurement ‘nodes’ and distributing this information to a range of stakeholders. But at that point different priorities emerge: IT teams are attracted by how readily data can be integrated and communicated whilst air quality professionals focus on how meaningful the air quality readings are.
Air quality readings from traditional air quality monitoring instruments – those which offer the most accurate readings – are generally accessed by direct download from the hardware or by hard-wired data infrastructure. A new generation of cloud-based air quality monitoring devices offers cheaper, smaller, more flexibly located measurement nodes, with all the benefits of cloud data management and integration. Leading air quality small sensor system, AQMesh, offers smart city partners an API data stream, which allows straightforward integration of real-time pollution gas and particle measurements into the smart city platform, and many low cost sensor systems offer something similar.
This is all very appealing and appears to bring air quality measurements into line with the array of city-wide measurements that the Internet of Things is expected to offer to a smart city. However, what if the air quality readings communicated to the public and other stakeholders are misleading, suggesting that air is clear when it is not, or suggesting that the city has a pollution problem that it does not? Either of these scenarios undermine the core case for smart city integration of air quality information. Read more…
Air quality professionals quite rightly demand evidence of accuracy from any new source of air quality readings. The most practical measure of accuracy is to compare a small sensor system which is co-located with – so measuring the same air sample as – a validated air quality station using reference method equipment. Laboratory test results are sometimes offered but small sensors may perform well in lab tests which use single, dry gases, but not in real-world monitoring where gases and particles are mixed and subjected to rapidly changing environmental conditions, such as temperature and humidity. The AQMesh study in Cambridge demonstrates the legitimacy of some small sensor air quality data.
AQMesh uses cloud-based correction for these influences to offer the best accuracy currently demonstrated by micro-sensing units. Teams of leading air quality experts are working worldwide with AQMesh and years of challenge and shared experience in a range of climates and conditions has allowed data processing to be refined to give reliable readings. This accuracy is combined with a robust platform and smooth data integration package to give the lowest possible risk and fastest solution for smart cities.
AQMesh showed its versatility in the BBC’s Inside Out feature on air quality (West region). The programme aired on 6th March but is available on iPlayer at www.bbc.co.uk/iplayer/episode/b08h4m30 until 5th April. AQMesh pods were used on the back of a bicycle and inside a taxi, to show the NO2 and particulate matter exposure experienced by a cyclist and a driver.
The feature, shown in the first 10 minutes of the programme, underlines the high levels of PM 2.5 that drivers in queueing traffic are exposed to and Professor Gavin Shaddick of the University of Bath provided an overview of the issues.
The fact that battery powered AQMesh pods can be used to measure air quality in such a range of locations has made it popular with broadcasters, as well as more typical users, such as local authorities, researchers or industrial customers. AQMesh has featured recently on BBC Newsnight and Channel 4 Dispatches.
Smart city projects increasingly seek to include air quality measurements. If city authorities and the public are being asked to act based on air quality readings they must be credible. Whilst cheap sensors may offer easily integrated readings, they offer poor value for money if the information they produce cannot be trusted by the public, smart city project managers and stakeholders.
The search is on for low cost air quality sensors which can be easily integrated into the chosen IT platform. Many commercially available sensors for key air pollutants such as NO2 and PM2.5 are working at their limits and, although these may seem “low cost”, often disappoint if adequate correction is not applied. Even sensors that are sensitive enough in a laboratory may struggle to distinguish a signal from the target gas or particulate matter from noise due to platform electronics, environmental conditions or interfering gases. Failure to adequately manage or compensate for these effects can mean that inaccurate readings from monitoring nodes are published.
Unfortunately individual air quality sensors used in isolation are not able to accurately measure air pollutants at the parts per billion levels required by current air quality legislation. A smart sensor system is currently the only way to overcome these issues and obtain data with any real value.
AQMesh is a sensor system which measures NO, NO2, O3, CO, SO2, PM1, PM2.5, PM10, TPC, noise, temperature, humidity and pressure in a single, compact unit with independent power and communication. Years of development have fine-tuned the performance of processing algorithms to give proven precision and accuracy. Multiple examples can be seen at https://www.aqmesh.com/performance/co-location-comparison-trials/, as well as a real-time feed comparing live AQMesh pod readings against those from a co-located reference station. The system has the added benefits that it is very quick and easy to install, is robust, can operate in environmental conditions from -20°C to +40° and has various data integration options.
Indoor air quality can also be controlled by smart buildings. In many cases HVAC systems bring in ‘fresh’ air to address CO2 build-up, but in cities that air is likely to be polluted – from NO2 and possibly from particulates. A smart system can control where air is drawn in and ventilation rates, depending on air quality at the various inlets, allowing optimisation of the internal CO2, temperature and humidity whilst minimising external pollutants brought into the indoor space. AQMesh pods can be readily installed at various heights outside and inside buildings, all feeding near-live data to a central control system. Read more…
Early versions of AQMesh were used across eight cities in a European funded Citi-Sense project ending in 2016, and performance has improved significantly since then, to the results seen in a recent Cambridge smart city pilot study (see https://www.aqmesh.com/cambridge/). AQMesh is now being widely used by national, regional and local government authorities across Europe to supplement their much more expensive reference monitoring locations and is providing valuable information to inform smart city and smart building strategies leading to better air quality for all.