Scientists have used the no-flying period caused
by the ash cloud to show for the first time that airports are
themselves significant causes of pollution. Although long suspected,
the fact that mass take-offs and landings are large pollution sources
could never be proved before, because aircraft pollution could not be
measured as separate from the pollution caused by vehicles operating
But an analysis of the first three days of the unprecedented closure of UK airspace, at Heathrow and Gatwick, shows that there is a definite air pollution caused by air traffic in the vicinity of airport hubs.
Pollution near both airports dropped significantly
during the first three days of the shutdown. During last Thursday,
Friday and Saturday, levels of two major pollutants, NO2 (nitrogen dioxide) and NOx (the generic term for oxides of nitrogen, taken together) fell virtually to zero.
nitrogen pollutants can exacerbate breathing difficulties in older
people and those suffering from cardiac conditions, and can react with
sunlight to form an even more damaging pollutant, ozone,
which causes the sort of "urban smogs" seen in Los Angeles. NOx and NO2
are particularly associated with jet aircraft, as they are produced by
the high-temperature mix of aviation with fuel.
new analysis has been produced by Ben Barratt and Gary Fuller of the
Environmental Research Group at King's College, London. The group said
yesterday: "This period of unprecedented closure during unexceptional weather conditions
has allowed us to demonstrate that the airports have a clear measurable
effect on NO2 concentrations, and that this effect disappeared entirely
during the period of closure, leading to a temporary but significant
fall in pollutant concentrations adjacent to the airport perimeters."
have always been fairly confident that there was this 'airport effect'
but we have never been able to show it," Dr Barratt commented. "The
closure gave us the opportunity to look at it, and there is a very
strong indication that it is the case."
researchers are also going to study the pollution effects of the fall
in airport motor traffic during the shutdown. Ed Dearnley, of
Environmental Protection UK, which specialises in air quality
campaigning, said yesterday: "This has been an excellent opportunity to
find out exactly what the environmental impact of airports really is."