Montpelier High School is the most polluted school in Bristol, and one of the worst across the country, when it comes to a ranking which combines the three main pollutants - ultra fine and fine particles and nitrogen dioxide (NO2).
The school, with others in the city, breaches the World Health Organisation (WHO) limits for all three main pollutants - recording well-over double to limit for exposure to NO2.
It ranks in the 84th percentile for most-polluted addresses in the UK.
WHO has set a limit of 5mcg/m3 for PM2.5, 15mcg/m3 for PM10, and 10mcg/m3 for NO2.
Exposure (for a year or more) to 30mcg of NO2 can lead to a 5.5% increased risk of disease related mortality. meanwhile exposure to fine particulate matter (PM2.5 and PM10) can cause asthma, promote cancer and reduce lung development.
Bristol City Council has introduced measures to reduce air pollution across the city, including the introduction of the Clean Air Zone (CAZ) which is due to begin on November 28.
Two secondary schools inside the CAZ are among the worst polluted in the city - St Mary Redcliffe and Bristol Cathedral Choir School.
Data collected by AddressPollution.org allows the public to search their postcode to see their own measurements, below are the 10 most polluted secondary schools in Bristol.