New research suggests a third runway at Heathrow could cause an extra 100 deaths a year linked to pollution from the airport.
The report, by Cambridge University and the Massachusetts Institute of Technology, shows a plan backed by mayor Boris Johnson for an airport in the Thames Estuary, would cut the number of deaths.
Scientists say the estuary scheme would see a 70% decrease in the number of people dying due to pollution caused by Heathrow.
Piers Hopkirk has our report:
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Hundreds of passengers were ordered to leave the terminal building and flights grounded after passengers suffered difficulties breathing.
Council leaders today called on the government to provide extra money to help resettle the youngsters in the capital.
An eyewitness said: "It was very unnerving. It was just after 12pm and there were suddenly police vans and cars everywhere."