• Susan

Some 65% of UK schools exceed safe air pollution levels finds #LetSchoolsBreathe campaign

One year ago, Cleantech platform Airly started installing air pollution sensors in schools across the UK to help children and parents understand more about air pollution levels.

The UK #LetSchoolsBreathe campaign initiative was started to help school children understand more about air pollution such as particulate matter (PM) and dangerous pollutant gases (like NO2, which is particularly harmful for children). The sensors monitored air 24 hours a day in the immediate vicinity of the school and they were able to view this data for free on the Airly app or map (airly.org/map/en).

The analysis, based on data from 36 schools based in nine UK cities, showed:

  • 35 out of 36 schools experience levels of PM2.5 pollution that exceed the safe norms set out by the World Health Organisation.

  • St Anselm's Primary School in London experienced the most polluted air, whereas Davidson's Mains School in Edinburgh experienced the least polluted air, with mean PM2.5 concentration below 5 ug/m3.

  • In the first quarter of 2022, the safe annual norm for Nitrogen Dioxide (NO2) was exceeded at 21 (65%) of the schools.

  • Every school experienced exceedances of diurnal (daily) norms for NO2 and PM2.5. For 50% of schools, these diurnal norms were exceeded every other day.

  • The remaining schools experienced diurnal PM2.5 exceedances every third day.


The highest concentrations of NO2 occur during the morning and afternoon. This is strictly correlated to traffic patterns, and is also at the times when pupils are entering and exiting the school. The highest concentrations of NO2 and PM2.5 occur in the vicinity of congested roads, in dense urban areas.



‘Pupils are exposed to high concentrations of NO2 and PM2.5 mainly during travel to school and in school playgrounds. Airly's outdoor monitors have been positioned in such a way as to be able to determine what kind of air students breathe when they are near the school building. Thanks to the data we have collected, we know the situation is far from perfect, but the first step towards pollution free schools has been made. This step is to make air pollution a topic for discussion among school communities, having the necessary knowledge and understanding of the causes of pollution and its impact on health, we give hope to the young generation into a world with cleaner and healthy air,’ commented Marcin Gnat, spokesman at Airly.