Although its global warming potential is much less per tonne than the other greenhouse gases it is present in the atmosphere in vastly greater quantities. Previous editions have included projected emissions of CO 2 as published by the DTI in 1995. At the time of writing, these projections are being reviewed by the DTI in the light of new data that have become available. A number of nitrogen compounds including nitrogen dioxide and nitric oxide are formed in the combustion of fossil fuel. Nitrogen dioxide is directly harmful to human health causing respiratory problems and can reduce lung function.
Oxides of nitrogen can also have adverse effects on plants, reducing growth.
In addition they contribute to acid rain. Derived from the incomplete combustion of fuels containing carbon. It is one of the most directly toxic of substances, interfering with respiratory bio-chemistry and can affect the central nervous and cardiovascular systems. Other pollutants can exacerbate the effects. The fitting of catalytic converters to all new petrol engine vehicles made after 1992 has reduced emissions of carbon monoxide from the 1992 level.