New European Union limits on nitrogen oxides (NOx) pollution may not block expansion of London Heathrow, says airport operator BAA. The "economic and social case" for building another runway at Heathrow is far stronger than the case for expanding London Stansted, BAA says.

However, European limits on atmospheric NOx will come into force in 2010, and due to nearby motorways "the area around Heathrow would break the limits regardless of Heathrow itself", BAA says. The sparser population and cleaner air around Stansted would make a new runway less likely to break the limits.

If BAA were allowed to impose tolls on traffic using the Heathrow approach roads, it could reduce vehicle pollution and partly offset the effect of another runway, says BAA. The revenue from the tolls would also help compensate people living nearby for the high levels of pollution. But the European Commission says it is "unlikely" BAA would be allowed to pay its way around pollution control laws in this way.

Source: Flight International