Air pollution is prematurely killing 13,000 people a year in Britain compared with fewer than 2,000 deaths a year from road accidents, a major study from the Massachusetts Institute of Technology has concluded. Of these, cars and lorries are thought to be responsible for 7,000 deaths, aviation almost 2,000, power plants 1,700 with the rest coming from shipping, factories and domestic emissions.
See http://www.guardian.co.uk/environment/2012/apr/20/air-pollution-killing-13000-people-year.