If you like me have arrived home from a day in London to find when you blow your nose it is full of dirt, then you might wonder whether it has any long term effects. According to this article it does, and it could be responsible for 4,267 early deaths. A study commissioned by the Mayor Boris Johnson has looked at pollution levels and air quality in London. It found that Bryanston and Dorset Square were the most polluted, followed by Marylebone High Street and the City of London. It also found that outer London had the most early deaths linked to pollution due its higher population. The figures amount to five or six deaths a year in central London (due to their low population) and around 12 people a year in areas like Penge, Bromley and Beckenham.