Indoor air pollution.

Indoor concentrations of pollutants often equal or exceed outdoor concentrations, and since most people spend 90% of their time indoors this constitutes a health threat much greater than that posed by outdoor pollution, which has received most of the attention in the U.S.A. The problem has been made worse by energy conservation measures which reduce ventilation. Thisarticle reviews recent research findings and their implications for pollution control programmes, and considers the further research that is needed.