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University of Cambridge measures seasonal variabilities in air quality in West Africa using AQMesh

28-Nov-2023Community | Networks | Research | UrbanAfrica

University of Cambridge measures seasonal variabilities in air quality in West Africa using AQMesh

It’s great to see the team at the Department of Atmospheric Chemistry, University of Cambridge using their AQMesh pods for another project, this time in Lagos, Nigeria and Yaoundé, Cameroon. The two pods were used as part of a year-long study into the health risks taken by people using open spaces in the cities for physical activity, measuring NO, NO2, O3, CO, CO2, PM2.5, PM10, pressure, temperature and relative humidity.

As there would be no access to reference equipment for data validation in either of the cities, the pods were ‘calibrated’ in Cambridge, before leaving UK (co-located with reference equipment at the Department of Chemistry). The co-location results shown in the paper are pretty good but it’s worth noting that the Cambridge team had chosen to use an older algorithm than was in general use by AQMesh at the time, following the ground-breaking Breathe London pilot study, for which gas algorithm version 5.1 had been used. V5.3 processing gives a further improvement in temperature correction, based on analysis of an ever-extending set of global co-location comparisons with reference.

A previous project had identified the informal places used by Lagos and Yaoundé residents to exercise, including vacant plots of land, next to roads and areas under and next to bridges: spaces with potentially high levels of air pollution. This information was used to choose a suitable monitoring location in each city. As has been observed in many parts of the world, patterns over time – or temporal profiles – can be very different for gases and particulate matter. In this case it seems that particulate matter was travelling long distances to create a dominating background level, with the source attributed to the Harmattan haze: a dry, dusty wind which blows from the Sahara towards western Africa.

The authors of the study concluded that their findings reinforce the need for long-term air quality monitoring to help guide behavioural changes that can protect health while exercising. They were able to offer some useful information, including the observation that weekends and periods outside the rush hour on most days tended to have the best air quality in both cities and so would be the best time for people to take exercise. Air pollution is also generally lower during the wet season, so taking physical exercise in a sheltered, outdoor space would maximise the benefits. It was not referred to in this paper, but the point was made at last month’s ASIC Ghana conference that awareness of the risks of air pollution may be much lower in Africa than in countries where we have been talking about it for longer. As ever, the biggest challenge will be achieving behavioural change.

AQMesh has been used regularly in Africa, and across the globe. For more information visit our website or contact us today.

*Image shows study locations and the installed low-cost air quality sensor devices. (a) Melen Mini-Ferme area, Yaoundé, Cameroon and (b) Admiralty Way, VI, Lagos, Nigeria.

What area does an air quality sensor system cover?

13-Nov-2023Fenceline | Industrial | Networks | Urban

What area does an air quality sensor system cover?

Or how many air quality measurement points do I need?

Annoying as it is, the answer is ‘it depends’. The list of factors which affects this not exhaustive but is based on our experience and we’ll try to be a bit more helpful afterwards.

  • Size, location and topography of site
  • Position and range of pollution sources and ‘receptors’ (such as communities or schools)
  • Wind direction and strength
  • Complexity of area being monitored, including multiple sources and street canyons
  • Analysis capability
  • Your budget!

Generally, the limiting factor will be budget. The clue is in the name with hyperlocal air quality monitoring, and pollution levels can vary hugely over short distances. NO measurements around streets, for example, are often significantly different from one side of the road to the other, particularly if there isn’t much wind and/or a street canyon effect. It is important to agree objectives and priorities in any city monitoring project, as it is simply not possible to meaningfully instrument the entire city, even with the biggest budgets. Even should budgets be effectively unlimited, the challenges of data management, quality assurance and interpretation get harder and harder the more nodes you have.

When monitoring air quality at the fence line at remote or industrial facilities, dilution of pollutants mixing with air around the site reduces the chance of a ‘spike’ being picked up from a plume, so generally the more measurement points that can be afforded, the higher the likelihood of detecting fugitive emissions, whether CO2, NOx, SO2, H2S, TVOC or particulate matter.

In either scenario, a hybrid network can help optimise the return on investment, so mixing a range of sensors with reference stations can help to fill gaps cost-effectively. The limiting factor with this is that any sensor used in the network has to provide comparable data. In theory a (very) low cost sensor could be used in high numbers to provide wide coverage, but if the cheap sensor does not have the necessary sensitivity (particularly when looking for low concentrations in a plume), data accuracy or comparability with other technologies (or even precision between themselves) in the network, there is a serious danger that project objectives will not be met and money will be wasted.

In our experience, the best way to achieve optimal coverage is the following recipe:

  • At least one well-maintained reference station (if a reference station is not available, diffusion tubes/passive samplers can be used to good effect)
  • As many good quality small sensor systems as you can afford
  • Normally one wind speed and direction sensor per site (this may be more complex if the wind direction is obstructed by topography or buildings) or local wind data may be available
  • Data analysis and quality assurance resource, with complete traceability
  • Calibrate small sensors against reference
  • Position small sensor systems precisely where required, free of infrastructure limitations, with autonomous power and communications
  • Carry out analysis to identify sources and distinguish background from locally-generated pollution
  • Stick to the sensor system manufacturer’s recommended maintenance procedures, however minimal, to ensure data reliability over the longer term
  • Follow local and international advice on quality assurance of data
  • Beware of big promises offered by AI – current local training of sensors comes with significant drawbacks

We are happy to provide more advice, dependent on your situation.

Breathe Easy Dallas chooses AQMesh

22-Jul-2023Community | Networks | Smart cities | Urban

Breathe Easy Dallas chooses AQMesh

AQMesh is being used as part of the newly revived Breathe Easy Dallas initiative – a project designed to measure and understand air pollution at neighbourhood level.

As published by The Dallas Express in March 2023, eight AQMesh pods have so far been used by the Office of Environmental Quality & Sustainability (OEQ) with a view to extending the network to 40 pods across areas that are suspected to have higher-than-average levels of air pollution.

Carlos Evans, director of the OEQ, confirms the Breathe Easy Dallas initiative will aid the development of policies that ensure safe and clean air within communities, and was reported to state “We have a pretty good understanding of regional air quality, but we don’t have a good understanding of neighbourhood level air quality”.

AQMesh has been used in a number of similar projects across North America – and elsewhere around the world – where networks of small sensor systems are used to supplement information available from larger reference sites to build up a picture of localised air pollution levels. In Minneapolis, USA, 50 AQMesh pods are used to determine air quality levels at different zip codes. In Kitchener, Canada, several AQMesh pods have been used to measure air quality levels at schools across the region.

Developed, manufactured, supplied and supported from the UK, AQMesh is available across North America via its authorised and trained distributor, Ambilabs. The product is a small sensor air quality monitoring system that can measure up to 6 gases as well as PM, noise and wind speed and direction.

AQMesh measures air pollution in Glasgow ahead of COP26 meeting

26-Oct-2021Environmental monitoring | Networks | Smart cities | UrbanUK

AQMesh measures air pollution in Glasgow ahead of COP26 meeting

Two AQMesh pods measuring airborne particulate matter have been loaned to the University of Cambridge, ahead of the COP26 meeting in Glasgow, to support research into measurement of particulate matter. The pods have been monitoring PM1, PM2.5, PM4, PM10 mass estimates and Total Particle Count, since April 2021. The team from the University of Cambridge, led by Professor Rod Jones, are using data from these units, which have the heated inlet option to minimise the effect of air moisture on readings, to support their work on understanding differences in chemical composition between particles.

The compact small sensor air quality monitoring system, designed to measure levels of pollutant gases in ambient air, also offers a non-dispersive infrared (NDIR) carbon dioxide (CO2) sensor, providing accurate outdoor CO2 measurements. As well as monitoring deviations in background levels of CO2, analysis of data from the system can also identify combustion plumes and provide an indication of whether the gases are being produced by a local or distant source, and from which direction.

Professor Jones has previously used CO2 data from AQMesh pods during the Breathe London pilot project, in conjunction with other AQMesh gas measurements. AQMesh offers a range of ambient air measurements relevant to climate change studies, including NOx, SO2, CO, CO2, Black Carbon, TVOC and methane. The Ecotec group – which owns AQMesh – specialises in methane leak detection and gas stream methane monitoring. Applications include pipeline methane measurement for energy-from-waste on landfill, biogas, waste water treatment and agricultural sites. Methane leaks are also detected using a range of laser-based sensors, providing a critical resource for methane-generating operations, including the oil and gas industry.

COP26 is the upcoming 26th United Nations Climate Change Conference, taking place in Glasgow, Scotland between 31st October and 12th November 2021. The aim of the conference is to progress global efforts towards the goals the UN Framework on Climate Change and the Paris Agreement – the legally binding international commitment to reduce carbon emissions, agreed at the COP21 conference in 2015.

CO2 emissions are a key factor in climate change and are largely caused through the burning of fossil fuels such as coal, gas and oil, which are burned to generate heat and electricity for the world’s power plants, cars, planes and industrial facilities, to name a few. Monitoring CO2 emissions is therefore vital in understanding, managing, mitigating and reducing sources of CO2 and its impact on the atmosphere and environment. Methane is an even more potent greenhouse gas and prompt identification of methane leaks is a critical part of the action plan to reduce greenhouse gas emissions.

AQMesh is an air quality monitoring ‘pod’ which can be mounted on a post, wall, fence or other position to measure ambient air pollution. Each pod measures about 20cm / 8 inches in each direction and weighs about 2Kg / 4lb. Sensor data is securely transmitted using the global mobile phone network to a cloud server, where carefully developed corrections for environmental conditions are made and data accessed by secure web login or API. Sensor options are offered on the basis that the level of sensitivity and selectivity for the target pollutant are fit for purpose, whether directed towards local air pollution or climate change pollutant monitoring.

Clean Air Day 2021: Local authorities use AQMesh to study air quality on school streets

17-Jun-2021Clean Air Day | Local authorities | Schools | UrbanUK

Clean Air Day 2021: Local authorities use AQMesh to study air quality on school streets

AQMesh has partnered with Warwick District Council and Stratford District Council to install air quality monitoring pods at six local primary schools, as part of this year’s national Clean Air Day.

AQMesh loaned 10 of its air quality monitoring systems to two local councils to be installed at the entrances of five schools across Warwick and Leamington Spa, with a further two installed at a primary school in Stratford-upon-Avon. The data from the pods will be used to show how pollutant levels vary throughout the day and could encourage parents to use alternative methods of travelling to school instead of driving.

Led by Global Action Plan, Clean Air Day takes place in the UK each year to bring communities and organisations together to help raise awareness and improve public understanding of air pollution, what causes it, how harmful it is and what can be done to reduce it. This year’s Clean Air Day is Thursday 17th June and will be focused on pollution’s impact on children, with the campaign’s key message being ‘Let’s protect our children’s health from air pollution’.

Councillor Christopher Kettle, Community Protection Portfolio Holder at Stratford District Council, said: “Stratford District Council is committed to supporting national Clean Air Day on June 17 to improve, in particular, air quality around schools. School pick-up and drop-off are some of the busiest times for local traffic – leaving the car at home can cut congestion, improve air quality and improve health.” Whilst Councillor Judy Falp, Portfolio Holder for Health and Community Protection at Warwick District Council added: “Contrary to popular belief, switching off your engine does not use more fuel or cause issues with the engine. It’s important for us all to be consciously aware of the little changes we can make that will have a big impact on the air quality in Warwick district.”

Jon Queralt, Associate Headteacher of Emscote Infant School, who have one of the pods outside their main entrance, also says: “We hope this will encourage families to give the car a day off and to walk, cycle or scoot to school whenever possible. As an eco-school we have always focused on teaching the importance of being environmentally aware by encouraging the children to walk to school, turn off the tap, switch off the lights and recycle. By having the air monitor installed and explaining to the children how it can help us to look after our environment, we can start to make even bigger changes which we hope will lead to a better quality of life and health for our community as a whole.”

AQMesh has been used in a number of similar school studies over the years to raise awareness about the effects of pollution on children’s health, particularly on how harmful idling engines can be during school drop-off and collecting times. For example, four AQMesh pods are currently installed around schools in Kitchener, Canada: the results of the study will hopefully encourage more parents to walk or cycle to school, or turn to electric cars, and the City of Kitchener may also consider implementing new idling laws. 22 AQMesh pods are also deployed outside schools across Newcastle, UK, that are located next to major roads. Newcastle City Council want to raise awareness of air quality issues and encourage fewer car journeys to and from school.

Recently, 30 AQMesh pods were used to carry out a study of schools throughout London, UK, as part of the Mayor’s ‘Streetspace for London’ plan. Based on the approach used in the Breathe London pilot network, AQMesh pods were installed to investigate the benefits of a new ‘School Streets’ initiative. The plan involved monitoring pollutant levels where sections of roads would be closed at certain times of the school day and comparing them with the levels at sites where the roads were not closed. Data from the AQMesh pods demonstrated that road closures at some of the school sites contributed to a 34% reduction in nitric oxide (NO) and a 23% reduction in nitrogen dioxide (NO2) during the morning drop-off period. The full report from that study can be found here.

In the UK alone it is estimated that poor air quality causes around 36,000 deaths each year, with that figure rising to seven million globally. The World Health Organisation (WHO) recognises that pollution is the largest environmental health risk the population faces. Long-term exposure to NO2 can cause and worsen asthma, particularly in children, and fine particle matter (PM2.5) can penetrate deep into the lungs and reduce lung development and reduce function. AQMesh is committed to supporting initiatives around the world to help measure, manage and mitigate global air pollution and its impact on people’s – particularly children’s – health.

Amanda Billingsley, Managing Director of AQMesh comments: “An appreciation of how much air pollution varies around schools – over time and short distances – can help us protect children from the highest pollution in the short-term, while we all work to raise awareness of causes of pollution and how to improve air quality in the longer term. We hope that this practical project will have an impact in and around the schools involved while we continue to engage at a wider level with global projects and the sophisticated analysis required to fully understand local and regional air pollution and how to reduce exposure.”

AQMesh network will be installed for monitoring around Canadian schools

09-Jul-2020Networks | Schools | Smart cities | UrbanCanada

AQMesh network will be installed for monitoring around Canadian schools

The collaborative research project between the City of Kitchener, Wilfrid Laurier University and Hemmera Envirochem Inc aims to compare air pollution levels around some of the city’s schools throughout the academic year and quieter summer season, to assess how local pollution is affected by idling vehicles.

Leading the project is Dr. Hind Al-Abadleh, researcher at Wilfrid Laurier University, who received a $50,000 grant from the Natural Sciences and Engineering Research Council of Canada to fund the installation of the AQMesh pods.

NO2, PM2.5 and PM10 are particularly harmful pollutants. Long-term exposure to NO2 can worsen asthma and reduce lung function. PM2.5 and PM10 are small airborne particles and are mostly formed in urban areas from vehicle fumes and construction equipment. PM2.5 particles are small enough to penetrate deep into the lungs and are linked to lung disease, heart attacks, strokes and cancer.

This pollution is particularly dangerous for young people; studies show that exposure to PM2.5 can impair childhood lung development, and Dr. Hind Al-Abadleh expects the study to show that pollutant levels increase during the typical school pick up and drop off times.

“Studying air quality around schools is important, since students spend so much of their day there” she comments. “I was shocked to learn this region has just one provincial air monitoring station. We need more”

She added, “If we can provide data that shows an increase in pollutants during these times, it could help speed up the electrification of the transit system.”

It is possible that the results of the study would also encourage parents to walk or cycle to school, or turn to electric cars. The City of Kitchener may also consider implementing new idling laws to help reduce exposure to pollution.

Ultimately, Dr. Hind Al-Abadleh would like to create a large network of local monitoring stations with citizen scientists in order to generate real-time pollution maps, much like initiatives in other global cities such as the Breathe London network in the UK, which uses 100 AQMesh pods as part of its hyperlocal air quality monitoring network across the city.

The five AQMesh pods are being supplied and supported by North American AQMesh distributor, Ambilabs.

Air pollution set to exceed limits at four out of five Breathe London sites

11-Nov-2019Breathe London | Networks | Smart cities | UrbanUK

Air pollution set to exceed limits at four out of five Breathe London sites

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.

AQMesh used by Guardian journalists in the UK to highlight air quality risks in London

20-Jun-2019Schools | Smart cities | UrbanUK

AQMesh used by Guardian journalists in the UK to highlight air quality risks in London

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.”

Urban Observatory monitors Newcastle with new generation of environmental sensors

20-Sep-2018Smart cities | UrbanUK

Urban Observatory monitors Newcastle with new generation of environmental sensors

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.

Car-free Cardiff achieves 69% air quality improvement

18-Jul-2018Smart cities | Traffic | UrbanUK

Car-free Cardiff achieves 69% air quality improvement

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.”