Abstract
Population exposures to ambient outdoor particulate matter (PM) air pollution have
been assessed to represent a major burden on global health. Ambient PM is a diverse
class of air pollution, with characteristics and health implications that can vary
depending on a host of factors, including a particle's original source of emission
or formation. The penetration of inhaled particles into the thorax is dependent on
their deposition in the upper respiratory tract during inspiration, which varies with
particle size, flow rate and tidal volume, and in vivo airway dimensions. All of these
factors can be quite variable from person to person, depending on age, transient illness,
cigarette smoke and other short-term toxicant exposures that cause transient bronchoconstriction,
and occupational history associated with loss of lung function or cumulative injury.
The adverse effects of inhaled PM can result from both short-term (acute) and long-term
(chronic) exposures to PM, and can range from relatively minor, such as increased
symptoms, to very severe effects, including increased risk of premature mortality
and decreased life expectancy from long-term exposure. Control of the most toxic PM
components can therefore provide major health benefits, and can help guide the selection
of the most human health optimal air quality control and climate change mitigation
policy measures. As such, a continued improvement in our understanding of the nature
and types of PM that are most dangerous to health, and the mechanism(s) of their respective
health effects, is an important public health goal.
Keywords
particulate matter - lung deposition - morbidity - mortality - climate co-benefits
