The toxic effects of air pollution are widely documented. In recent years, however, there has
been an increasing interest in the study of the health effects of particulate matter (PM), a
previously unexplored constituent of urban air pollution. Exposure to increased levels of PM
of respirable size is strongly and consistently associated with increased cardiopulmonary
morbidity and mortality. Conversely, improved air quality appears to correlate with
decreased mortality. Particulate matter is a mixture of inorganic and organic components …