Most of the airports were above EU recommendations

Birmingham was named as one of the worst offenders in a report from the Chartered Society of Physiotherapy.

Its report found it exceeded EU levels of nitrogen dioxide by up to 75%.

But airport bosses said the study was conducted by the side of the M42, where 90% of the traffic had nothing to do with the airport.

The airport said it has had a monitoring site on the airfield since 1995 which is overseen by both Solihull and Birmingham councils - the nitrogen dioxide levels had never exceeded the recommended maximum.

John Morris, head of corporate and community affairs at the airport said: "Using a survey station plonked on top of the M42, when we have an independently-verified station on site, is going to give misleading results so far as the airport activity is concerned."