Grosvenor Place, which runs alongside the Queen's London residence, had the highest level of the toxic gas nitrogen dioxide in 2012.
Researchers found 152 milligrams of the gas per cubic metre of air, with a main contributor being diesel engine fumes. The EU legal limit is 40.
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Barnet Council ran the school, which was an institution for young people with learning difficulties.
Bowers pleaded not guilty of assaulting his ex-fiancee Sophia Cahill in Croydon in January.
A Trades Union Bill to alter the strike ballot threshold was announced in the Queen's speech during the state opening of Parliament.