Aircraft pollution

Emissions from aircraft are difficult to quantify once they are airborne; once they exceed 1000 metres from the ground the effects of high altitude winds disperse the emissions. Below 1000 metres, the exhaust gases are principally oxides of nitrogen, nonmethane volatile organic compounds and carbon monoxide. The level of emissions depends on the type of aircraft.

Air pollution has been directly linked with airport operations at ground level. In December 2003 the government published its Air Transport White Paper, which set out the UK’s policy framework for aviation for the next 30 years. The government has chosen Stansted as the location for the first new runway. It has also said that a second runway should be built at Heathrow, providing that environmental issues associated with it can be resolved.

The government believes there is a strong case for seeking to secure large economic benefits through the addition of a third runway at Heathrow. At the same time, however, it recognises that these strong economic arguments must be weighed against the serious environmental impacts. The main issue is considered to be air quality.

The government acknowledged that nitrogen dioxide objectives in the airport vicinity were already being breached. In terms of justifying the third runway, it was clear therefore, that the most difficult issue is compliance with mandatory EU limits for nitrogen dioxide from 2010.

Analysis and sensitivity testing of air quality was carried out by the Department for Transport to explore what would be needed to reduce emissions. Possible measures include:

improvements from airport operations (clean airside vehicles, greater use of fixed electrical ground power, more efficient taxiing)
economic incentives in relation to aircraft emissions for delivering technological improvements; traffic management measures eg road charging; slow build-up of use to reduce emissions in early years

The government advises that even with the full implementation of a package of tough measures, many people may still be subject to exceedences of air quality limit values. For these reasons, the government postponed its proposals, and it does not expect the construction of a third runway before 2015, with a probable opening date of 2020. No plans are proposed for further motorway widening. The transport solutions will be based on improvements to public transport (likely to be several million pounds on new rail infrastructure). The government advises that road user charging should be considered.