Denmark has earmarked DKr30 million (€4 million) over the next two years to subsidise up to 30 per cent of the cost of fitting and promoting diesel particulate filters.

The capital, Copenhagen, will have designated 'environmental zones' from the 1st October 2004, as part of a series of initiatives to reduce harmful emissions.

Other measures being considered include making it a legal requirement for existing trucks and buses to fit the equipment, the beginning of a process of compulsory installation

Tax incentives feature heavily in the proposals, with breaks being mooted for truck and bus fleet owners who fit the filters, for people who use sulphur-free fuels, and for private car owners who comply with government standards.

The Institute for Environmental Assessment has calculated that 1,250 lives a year and up to DKr 83 billion on health spending over 15 years would be saved by fitting particle filters to all diesel engines.