Pollution from lead in petrol

Pollution by petroleum itself is very largely confined to the contamination of water—sea water or fresh water—usually caused by accidents, and is a local problem. On the other hand, air pollution by products of combustion occurs whereever petroleum products are used for the production of heat or power. Normally, the natural dispersion processes in the atmosphere are sufficient to prevent the concentrations of pollutants exceeding sale limits, but if emissions are too great for this to occur they are subject to legal regulations. Examples are emissions of sulphur dioxide from power station chimneys were ground level concentrations are controlled by the height at of the chimney, and emissions from motor engines in districts such as Los Angeles where they would cause photochemical smog. In recent years, in Great Britain, there has been growing public disquiet about another aspect of motor exhaust emissions, namely lead, which is added to petrol to improve performance. This issue has become highly emotive as it has been linked with the possibility that the intelligence of young children may be adversely affected by exposure to lead from motor exhaust. This paper has been written to provide background information to the facts and guess work in this field.