New figures have revealed the air near Buckingham Palace is the most polluted in the UK.
The Department for Environment, Food and Rural Affairs (DEFRA) figures show that Grosvenor Place, which runs adjacent to the Queen's London residence, produced the highest levels of toxic gas nitrogen dioxide (NO2) in 2012.
The average level of gas was 152 micrograms per cubic metre of air.
This figure is almost four times the European legal limit of 40 micrograms per cubic metre.
Oxford Street had the second highest level of pollution, the BBC reports.
According to The Sunday Times, tourist attractions including the National Theatre, Covent Garden, the Houses of Parliament and the street outside Hamley's were also exposed to high levels of pollution.
Environmental campaigner Simon Birkett, director of Clean Air in London, told newspaper: "The thought that hundreds of thousands or millions of tourists and Londoners in a year may be exposed to air pollution this high is deeply troubling."