Points out that increased thermal insulation and draughtproofing of homes can increase the risk to health of indoor air pollution. Includes condensation as a pollutant along with associated mould growth. Notes collaboration by Pilkington the glass company and the Timber Research and Development Association plus Laing the housebuilding group, to combat condensation by passive ventilation. Treats sources of indoor air pollution - formaldehyde, asbestos, gas appliances, tobacco smoke, thoron, radon. In some homes in the UK the radon level is so high that occupants face a significant risk of contracting lung cancer. Treats research into ways of reducing level of radon and other pollutants in homes. Recommends the controlled introduction of adequate amounts of fresh air. Notes the dangers of indoor air pollution in offices - the sick building syndrome.