Survey exposes 'polluted' schools
It charts levels of three pollutants - released into the atmosphere through high volumes of diesel - which are likely to exacerbate asthma in teenagers.
The UK already has the world's highest incidence of the condition with one in five 13 and 14-year-olds affected.
The survey has been produced two months before councils will have to draw up maps showing pollution hotspots.
The highest levels of sulphur dioxide, nitrogen dioxide and fine particles in the air were found to be in the square kilometre surrounding Dagenham Priory comprehensive in Essex.
All three could provoke asthma attacks in children - and levels of some pollutants may be even higher inside schools, according to the National Society for Clean Air and Environmental Protection.
Levels of nitrogen dioxide and particulate matter in the square kilometre around Dagenham Priory were more than twice as bad as the school with the second- highest levels of pollution, according to the survey. Those for sulphur dioxide were around 10 per cent higher.
Barking and Dagenham council, however, disputed the findings and said it was undertaking a comprehensive review of air quality in the borough.
"Initial work indicates that pollutant levels at the school are not particularly high and certainly do not give cause for concern," said a spokesman.
"Many areas of central London have much higher backgrounds of the pollutants referrred to ... and Barking and Dagenham as a whole compares very favourably with other London boroughs."
Other schools in highly-polluted areas are: All Hallows RC high school in Salford, Colegi Espanol in West London and College Park School in Westminster.
The survey by Internet property company Freeagents.co.uk looked at the air quality of 5,000 English secondaries, private and special schools using National Atmospheric Emissions Data from the Department for the Environment, Transport and the Regions (DETR). It did not consider microclimates around schools or weather conditions.
As well as looking at sulphur dioxide, nitrogen dioxide and fine particles, it tracked levels of carbon monoxide and volatile organic compounds which have been linked to cancer.
Half of the 10 worst-affected schools were private establishments in London.
All of the schools with the cleanest air surrounding them were fee-paying.
Embley Park, a private school in Romsey, Hampshire, topped the league with the lowest score for carbon dioxide, nitrogen dioxide, fine air particles and sulphur dioxide.
A spokeswoman for DETR said: "We are concerned about the amount of traffic around schools not only for road safety reasons but because of the emissions into the atmosphere."
Paul Harrison, acting director of the Medical Research Council Institute for Environment and Health, criticised the survey for failing to measure pollution inside schools. He said hazards such as dust, glue and paint and oil and gas fumes should be assessed.
The Government expects the current stable pollution levels to fall in the next five years as a result of its national air quality strategy which sets levels for eight pollutants.
Meanwhile, there is bad news for parents driving their children to school - pollution levels inside cars are between three and five times higher than those outside.