Why are children especially vulnerable to pollution?

Children’s lungs and brains are developing, and research has shown that exposure to high levels of pollution can stunt lung growth, increase the likelihood of developing asthma and impair brain development.

When are children most exposed to pollution?

Research published by Unicef in 2018 showed that children are being disproportionately exposed to pollution whilst they are on the school run and at school.

Children spend nearly 8 hours at school - about 30% of their day, yet during this time they receive nearly 44% of their exposure to air pollution. Likewise, children only spend 7% of their day travelling to and from school but receive 15% of their daily exposure to air pollution during this time.

How can we decrease children’s exposure to pollution at schools?

Firstly, efforts should be made to reduce the source of the pollution as much as possible, which is usually road traffic such as buses, cars and vans. This could be done through:

• Closing the road by the school to traffic at school pick-up and drop-off times (here’s an example).

• Running an anti-idling campaign to stop drivers idling while waiting to pick up or drop off children at the school.

• Campaigning to have a bus stop moved away from near borders of the school, as they’re the source of a lot of pollution (Here’s an example of a campaign).

Secondly, schools could consider mitigation measures, such as:

• Moving entrances to the school and play areas away from the borders of main roads, which is where pollution levels are usually highest, and onto quieter streets.

• Putting up a green screen along the side of the school site that faces any busy roads, which will help to stop some of the pollution entering the school.

• Planting hedges, trees and pollution-absorbing vegetation on the site, although it is recommended that schools seek advice on this, as in some cases tree planting can actually trap pollution on site.

When people say pollution levels are over the legal limit, what do they mean?

The legal limit for nitrogen dioxide (NO2) is an annual mean of 40 µg/m3 (micrograms per metre cubed of air). If pollution levels on the school site exceed the annual mean of 40 µg/m3, then it can be described as being ‘over the legal limit’. Pollution levels can vary month by month, due to weather conditions and other factors, which is why the annual mean is used, rather than a monthly mean.

It’s worth noting that there is no safe level of pollution, so even if your school has levels below the legal limit, it’s still worth taking action to try to reduce pollution and exposure as much as possible.

Green Screens – are they the solution?

Research has shown that green screens can reduce the pollution levels by as much as 22% immediately next to the screen. However, their impact on the pollution levels across the school playground is less clear. Reducing the source of pollution (usually from road traffic) should be the priority.

Monitoring – how can we find out what pollution levels are like at the school?

If you’re in London, you can use the tool on this webpage to look up pollution levels at your school.

The simplest way to measure pollution is to use diffusion tubes, which measure NO2 levels. The small tube can be put up, out of reach, at different locations (ideally three different locations), such as the front gate, back of the playground and middle of the playground. After a month, they are taken down and sent off for analysis.

Tubes can be:

• Sometimes handed out by charities, such as Friends of the Earth.

• Purchased for as little as £7/tube from analysis labs, such as Gradko.

It’s worth contacting your local authority air quality officer, as they may have been monitoring the pollution levels at your school already. Or they may be able to add your school to the air pollution locations they monitor.

How can I plot a low pollution route myself?

walkit.com is a web tool that can plot you a low pollution route in many cities in the UK.

GLA’s Clean Air Route Finder is an interactive map of London that allows you to put in any route and be shown a low pollution walking option.