School Filters programme

The Mayor wants every child to breathe clean air in and around their school. In the early years of young people’s lives, cleaner air can have a life-changing impact on their health and wellbeing. Research on London's air quality shows that children living in polluted areas are more likely to develop smaller lung capacity than those growing up with cleaner air.

That’s why, in February 2024, the Mayor announced £2.7m of funding to deliver his School Filters programme to help improve air quality in the classrooms of more than 200 schools across London.

The programme will provide:

• HEPA (High Efficiency Particulate Air) filters (also referred to as ‘air purifiers’) to the classrooms of each participating school to help reduce levels of the key pollutant PM_2.5
• in-person assemblies and classroom activities on air quality and active travel.
• a comprehensive maintenance and support service for schools including replacement filter cartridges
• indoor air quality monitors, evaluation, and reporting to understand the impact of the filters.

In 2024, the Mayor commissioned a research project to better understand which types of filters are effective and practical in a classroom environment. The final report by WSP found that PM_2.5 levels in classrooms with HEPA filters were between 27 and 68 per cent lower compared to those without. It also found that HEPA filters were practical in a classroom setting and were well received by school staff.

Download the Air Filters in Schools report PDF

The Mayor audited 50 primary schools and 20 nurseries between 2017 and 2020 to identify the types of measures that could improve and reduce exposure to poor air quality.

Recommendations from the audits included:  

• moving school entrances and play areas away from busy roads
• 'no engine idling' schemes to reduce emissions from the school run
• reducing emissions from boilers, kitchens and other sources
• local road changes including better road layouts, restricting the most polluting vehicles around schools and pedestrianisation by school entrances
• adding green infrastructure like ‘barrier bushes’ along busy roads and in playgrounds to help filter fumes
• encouraging students to walk and cycle to school along less polluted routes
• using indoor air quality filters to improve air quality in classrooms.

Six nurseries were selected to trial indoor air filtration systems to determine whether they could have a positive effect on improving indoor air quality.

Download the report highlighting the impacts of indoor air filters PDF

Taking recommendations forward

The Mayor has provided the following funding for schools and nurseries to carry out the recommendations of the audits: 

• £500,000 was made available to deliver non-transport recommendations at all 50 schools audited. Each school received £10,000 from the Mayor matched by schools and boroughs. In addition, at least £300,000 was made available from the Mayor's Greener City Fund to deliver greening measures at any school in areas exceeding legal pollution limits. 
• The Mayor’s Air Quality Fund supports projects including school streets, green infrastructure and anti-idling action which are recommended through the audit.  
• TfL’s Local Implementation Plans provides funding and support for Boroughs to deliver the transport recommendations for schools and nurseries.  

Master report and toolkit for schools

The Mayor wants to encourage London boroughs to audit schools within areas of higher pollution and the school audit toolkit can help. It can be used by schools, nurseries, workplaces, hospitals and other organisations keen to reduce their exposure to air pollution.

• Download the School Air Quality Audit toolkit PDF

A master report has also been made available which provides an overview of the audits including actions that can be taken to address air quality at schools.

• Download the School Air Quality Audit report PDF

School audit reports

The 50 primary school air quality audit reports are available below. Search by location in London: