Can I monitor air pollution?

Not easily - monitoring air pollution is a complex scientific process. The measurements of air pollutants disseminated on the London Air Quality Network are generated by specialist equipment which costs tens of thousands of pounds. This provides measurements which can reliably be used to assess exposure, affect government policy and keep the public informed.

There are cheaper, less accurate methods of measuring some of the gaseous pollutants, such as nitrogen dioxide, using diffusion tubes. These cost only tens of pounds and each tube can be kept in place for a few weeks and then sent to a laboratory for analysis. However, each tube only provides an average concentration over a short period, which may not be representative of ‘typical’ conditions. There are specific procedures in place for the use of diffusion tubes to allow results to be compared to national air quality standards and results of monitoring carried out by local authorities. For more information click here.

Recent advances in small sensors offer of exciting opportunities for citizen science and for people to measure their own pollution exposure. However these sensors are normally based on technologies that were first developed for workplaces and they can give misleading results when used to measure the pollution that we experience in everyday London. Defra’s independent Air Quality Expert Group (AQEG) are developing on going guidance on this field https://uk-air.defra.gov.uk/library/aqeg/pollution-sensors.php .

Monitoring indoor air quality can be tricky, as there are many possible sources of pollution, and it can be hard to know where and when to measure.

• Some London Boroughs do use diffusion tubes, for example Ealing.