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Air pollution worse inside some London classrooms than outside

Whole-school issues
London’s most polluted primary schools are being given access to a new £1 million fund in a bid to make immediate improvements to protect pupils from toxic air inside classrooms. Pete Henshaw reports

An investigation by academics has found that air pollution caused by traffic emissions is worse inside London classrooms than outside.

The study, commissioned by the Mayor of London, found that outdoor nitrogen dioxide and particulate matter (PM) pollution – much of it caused by diesel vehicles as well as tyre and brake dust – is infiltrating classrooms, where pupils spend much of their time.

Young children are more vulnerable to airborne pollutants than adults and the report warns that they are breathing in fine particle pollution – PM10 and PM2.5 – at levels higher than the World Health Organisation (WHO) guidelines.

For PM10, the report finds that pupils are being exposed to higher levels of pollution inside the classroom than outside.

The report, which was compiled by the UCL Institute for Environmental Design and Engineering and the Department of Chemistry at the University of Cambridge, examined five London primary schools and one nursery.

It states: “Mean indoor PM10 and PM2.5 levels recorded in all classrooms in both seasons were higher than 20μg/m3 and 10μg/m3 respectively, indicating that annual personal exposure to PM in the classroom may be higher than WHO 2010 guidelines. In most classrooms, PM concentrations were above daily guideline values.

“School-aged children spend a great deal of time inside school buildings. They are more vulnerable to airborne pollutants than adults not only because of their narrower airways, but also because they generally breathe more air per kilogram of body weight.

“The exposure of children’s developing lungs to air pollution can result in reduced lung function that persists through to adulthood, (and) increasing susceptibility to respiratory and cardiovascular diseases.”

The UK has the highest prevalence of childhood asthma among all European countries and school represents a significant exposure environment that “can trigger health symptoms among susceptible children”, the researchers warned.

The report adds: “A review of existing studies concluded that children living or attending schools nearer high-traffic density roads were exposed to higher levels of motor vehicle exhaust gases and had higher incidence and prevalence of childhood asthma and wheeze.

“A higher incidence of childhood asthma was positively associated with exposure to nitrogen dioxide (NO2). Exposure to particulate matter was also associated with a higher incidence of wheeze in children.”

The findings suggest that the protection offered by school buildings increase the further away they are from the busiest roads and that airtight buildings may offer greater protection.

Last year London mayor Sadiq Khan launched a programme of air quality audits, which have now been carried out in 50 schools across 23 London boroughs. The schools were shortlisted according to their exposure to NO2 and the number of pupils per school and the audits have made recommendations to help protect pupils.

These include major infrastructure measures, such as closing roads or moving playgrounds and school entrances, as well as targeting indoor pollution using improved ventilation systems, and installing “pollution barrier” hedges, tackling engine idling outside schools and promoting cycling and walking.

A new £1 million fund has now been unveiled to help give each of the 50 audited schools a £10,000 starter grant and to enable any other London schools located in areas exceeding legal air pollution limits to apply for green infrastructure funding.

The fund includes £300,000 to deliver green infrastructure at any London school located in an area exceeding legal pollution limits and £250,000 to launch a new nursery audit programme that will trial filtration systems to reduce indoor air pollution at 20 of the most polluted nurseries in the most polluted areas.

Mr Khan said: “Our air quality audits set out to reduce pollution in and around school premises. City Hall is also offering funding to the 50 audited schools – as well as other schools and nurseries located in high-pollution areas – to help them make immediate changes. Air pollution is a national health crisis that is putting the health of children at risk.”

St Mary’s Bryanston Square Primary School in Westminster is among the 50 audited schools and improvement work has already begun.

Improvements at St Mary’s include installing and testing a new filtration system to reduce pollution inside the school, a green wall of plants to screen students playing outside from nearby traffic pollution, the trialling of road closures at key times of the day, and involving pupils in a “no-engine idling” campaign to help educate their parents on reduce harmful emissions.

Headteacher Emily Norman said: “We are very pleased to be part of the Mayor’s air quality audit, as it has identified ways to tackle air quality, such as closing the street to traffic at key points in the school day and air filtration inside the classrooms. This will make a real difference to our children’s wellbeing at school, and significantly enhance the school’s work in this area.”