Figures released by the Department for Transport show that there has been a rise in the number of flights that are polluted with contaminated air. This year there were 72 recorded cases in the first six months of the year, compared to 109 cases for the whole of 2006. Scientists have estimated that 200,000 passengers a year are exposed to air contaminated with fuel vapours. The worst record is with the Boeing 757 which had 43 cases.