asked the Secretary of State for the Environment what are the principal sources and the percentage of atmospheric lead derived from each source in (a) heavy industrial centres and (b) rural areas.
The principal sources and percentages of atmospheric lead in heavy industrial areas are petrol-engined vehicles—90–95 per cent.—and industrial sources—5–10 per cent. Generally in rural areas, petrol engined vehicles constitute the only source of atmospheric lead; in such areas atmospheric lead concentrations are typically one-tenth of those in industrial areas. Lead inhaled from the atmosphere accounts for only about 10 per cent. of most people's total lead intake.