§ Mr. Waldegrave
Nitrous oxide is generated almost entirely by natural processes and its concentration in the atmosphere is low. The question is taken to refer to nitric oxide and nitrogen dioxide arising from high temperature combustion processes and from nitrogen compounds in fossil fuels. Information on emissions of oxides of nitrogen is given in "The Digest of Environmental Pollution and Water Statistics" published by my Department. The latest figures (for 1981) are: industrial sources 67 per cent., vehicle emissions 26 per cent., other sources 7 per cent.