Adverse health impacts of air pollution--continuing problems.

Evidence has been published that current levels of fine particulate pollution are associated with a wide range of adverse health outcomes, including accelerated mortality. Tropospheric ozone, often in association with aerosol sulfates, is similarly and independently associated with increased emergency visits and hospital admissions for acute respiratory disease, and there are sound reasons for suspecting that asthma may be worsened by exposure to it. Whether nitrogen dioxide is important at current levels in inducing adverse health effects is unclear. Although the combination of sulfur dioxide and particulate pollution that results from uncontrolled coal burning has been known for 30 years to be harmful, the independent role of sulfur dioxide cannot yet be precisely defined. A first report has appeared that ambient levels of volatile organic compounds may be associated with symptoms. Current efforts to assess the costs, in economic terms, of the adverse health effects attributable to air pollution are likely to be intensified.