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.”
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.
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.