School Streets restrict vehicle access during drop-off and pick-up times. The study was commissioned by the Greater London Authority (GLA) in association with the FIA Foundation and Bloomberg Philanthropies.
Quantifying the effects of interventions to improve air quality is notoriously difficult, and AQC staff were part of Defra’s Air Quality Expert Group (AQEG) which reviewed available approaches and their challenges. The School Streets interventions were particularly problematic since they coincided with significant disruptions to travel behaviour caused by the COVID-19 pandemic. There was also insufficient time to collect comparable measurements before the School Streets were implemented.
AQC, working with partners of the “Breathe London” project, carried out monitoring at 30 sites in Brent, Enfield and Lambeth over a period of 12 weeks. Sensors were installed adjacent to, and at the ends of, sections of road that were closed at certain times of the day on school days as part of the School Streets initiative. Comparator sites were also installed outside schools where no interventions were implemented.
A basic interpretation of the measurements showed no evidence that the School Streets had had any effect on air quality. However, AQC employed a variety of complex statistical methods to tease out more insightful trends. These were able to show a clear benefit to air quality outside several of the Schools.
AQC’s analysis showed average reductions in nitric oxide (NO) concentrations of up to 8 µg/m3 (34%) during the morning intervention period, which equates to a reduction in the daily average (school day) concentration of approximately 5%. The resultant reduction in nitrogen dioxide (NO2) during the school drop-off period was estimated as being up to 6 µg/m3 (23%). The morning intervention alone thus reduced daily average NO2 by up to 0.4 µg/m3, or 2%.
AQC thus showed that School Streets can play a role in reducing peak exposure to pollution concentrations outside of schools. This evidence was welcomed by both GLA and parents.
The full report can be downloaded from the GLA website: https://www.london.gov.uk/WHAT-WE-DO/environment/environment-publications/school-streets-air-quality-study
View all case studies