In 1990 the federal government set their standards for acid deposition, four years behind the State of Minnesota.

Changing the nitrogen cycle also increases photochemical smog and acid deposition.

There were two contenders for this: acid deposition (in all its various forms) and ozone.

It is generally accepted that increasing lake acidification due to acid deposition has caused fish kills and stock depletion (figure 4.14).

Some bird and animal populations living in forests damaged by acid deposition have been shown to have declined recently.

These will all reduce emissions from fossil fuels and so help combat global warming and acid deposition.

Ninety per cent of their acid deposition is caused by other countries.

There is growing evidence to suggest, however, that acid deposition and ozone pollution are taking their toll on the UK environment.

This can be responsible for as much as 20 to 60% of total acid deposition.

The institute stresses, however, that this should not be used to justify widespread use of such fertilisers, a major contributor to acid deposition.