Health effects of outdoor and indoor air pollution

Outdoor air pollution and health : despite the overall reduction in air pollution over the years, with the noteworthy exception of carbon dioxide, scientists agree that there remain plausible statistical relations between different atmospheric pollutants and the short-term and long-term risk of certain respiratory and cardiovascular diseases. Although the relative risks are weak, the universal nature of the exposure can incur considerable medical costs. The frequently expressed fear of synergy among pollutants appears unfounded, as the current marginal risk already results from an extremely complex mixture of pollutants whose concentrations have been decreasing for more than 30 years. Attention is currently focusing on the roles of ozone and fine particles. Better knowledge of fine particle origin, composition, size and potential toxic mechanisms is needed. Indoor air pollution and health : the possible medical consequences of exposure to the pollutants of room air is an emerging issue. Domestic exposure combines pollutants contained in outdoor air with those of the habitat itself Exposure can occur for up to 80 % of the day Recent investigations suggest that 9 % of homes are highly polluted and that 45 % are only slightly polluted, but epidemiological studies are still too rare to draw conclusions, except in the case of allergens, tobacco smoke, radon, and asbestos. Based on the intrinsic properties of toxins present in room air, one might expect irritant, immunotoxic, neurotoxic, carcinogenic and reprotoxic effects. Reference values are needed to assess associated health risks but are likely to be highly controversial.