Dozens of schools and colleges in Bracknell Forest are in areas with potentially dangerous levels of air pollution.
That is according to research by the British Lung Foundation which shows they are among thousands across England in polluted areas.
The charity is calling for stricter laws and a new cross-government air quality minister to protect the public from the effects of toxic air.
PM2.5 is the most harmful type of air pollution for human health and particularly affects children and people with lung conditions such as asthma, says the BLF.
It can penetrate deep into the lungs and even the blood, increase heart diseases and lung cancer, and leads to thousands of early deaths a year.
Traffic fumes are a major source of the pollutant, which can also be produced through industrial emissions and wood burners.
The WHO says concentrations of PM2.5 should not exceed 10 micrograms per cubic metre on average in the year – half the current legal limit in the UK of 20 micrograms.
The research used government data collected in 2019, which provides estimates of PM2.5 for small areas across the country.
Across the South East, 2,427 nurseries, schools and colleges were identified as being in areas where WHO-recommended limits were breached.
These accounted for 28 per cent of more than 8,500 nationally that were deemed to be in highly polluted areas.
The BLF is urging the Government to produce a national health protection plan for England to be overseen by a new air quality minister, and stronger air quality laws in line with the WHO limits.
Professor Stephen Holgate, medical adviser at the BLF, said: “We’ve known about the deadly harm air pollution can cause for decades, it’s time now for urgent action.”
Last year, Prof Holgate gave expert testimony at the high-profile inquest of nine-year-old Ella Kissi-Debrah, in which the coroner concluded that air pollution had contributed to her death from asthma.
The coroner said in a statement that nitrogen dioxide and particulate matter levels near her home in the London borough of Lewisham were in excess of WHO guidelines, and were mainly caused by traffic emissions.
Prof Holgate added: “We must honour Ella’s legacy by acting now and protecting other vulnerable people from the harmful effects of toxic air.”
Environment minister Rebecca Pow said: “Air pollution has reduced significantly since 2010 with emissions of fine particulate matter falling by 9 per cent and emissions of nitrogen oxides at their lowest level since records began. However, we know there is more to do.
“Our landmark Environment Bill will set at least two ambitious legally-binding air quality targets, with a primary focus on reducing exposure to particulate matter pollution.
“As part of this, we will consider the World Health Organization’s guidelines for PM2.5.”