The potential impacts of climate variability and change on air pollution-related health effects in the United States

Climate change may affect exposures to air pollutants by affecting weather, anthropogenic emissions, and biogenic emissions and by changing the distri bution and types of airborne allergens. Local temperature, precipitation, c louds, atmospheric water vapor. wind speed, and wind direction influence at mospheric chemical processes, and interactions occur between local and glob al-scale environments. If the climate becomes warmer and more variable, air quality is likely to be affected. However, the specific types of change (i .e., local, regional, or global), the direction of change in a particular l ocation (i.e., positive or negative), and the magnitude of change in air qu ality that may be attributable to climate change are a matter of speculatio n, based on extrapolating present understanding to future scenarios. There is already extensive evidence on the health effects of air pollution. Groun d-level ozone can exacerbate chronic respiratory diseases and cause short-t erm reductions in lung function. Exposure to particulate matter can aggrava te chronic respiratory and cardiovascular diseases, alter host defenses, da mage lung tissue, lead to premature death, and possibly contribute to cance r. Health effects of exposures to carbon monoxide, sulfur dioxide, and nitr ogen dioxide can include reduced work capacity, aggravation of existing car diovascular diseases, effects on pulmonary function, respiratory illnesses, lung irritation, and alterations in the lung's defense systems. Adaptation s to climate change should include ensuring responsiveness of air quality p rotection programs to changing pollution levels. Research needs include bas ic atmospheric science work on the association between weather and air poll utants; improving air pollution models and their linkage with climate chang e scenarios; and closing gaps in the understanding of exposure patterns and health effects.