Buckingham Palace has the worst air pollution in the country, four times the safe level of toxic gas mandated by the EU.
Researchers from DEFRA found 152 milligrams of the gas per cubic metre of air, the culprit being diesel engine fumes. The EU legal limit is 40.
Other highly polluted areas include Oxford Street near Marble Arch, which registered at 150 micrograms, and Trafalgar Square on 138 micrograms.
Many of the London streets outside London's key attractions were named as dangerously polluted, including Madam Tussauds, Hamleys Toy Shop and Covent Garden.
TOP STORIES TODAY
Simon Birkett, Founder and Director of Clean Air in London, said in a statement: “These levels of nitrogen dioxide (NO2) are nothing short of staggering.
“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.”
A spokesman for Boris Johnson told the Evening Standard: “Since the Mayor was elected, NO2 emissions have reduced by 20 per cent and the number of people living in areas exceeding NO2 limits has halved but he fully recognises the need to take further action.
“This includes the introduction of the world’s first Ultra-Low Emission Zone in central London from 2020, tougher requirements for taxis from 2018 and a £20million fund to tackle local problem areas.
“These most ambitious measures will deliver enormous economic and environmental benefits for central London and will make this global city an even better place to live, work and visit.”