Abstract
Many studies have found associations between fine particulate matter [PM with aerodynamic diameter ≤ 2.5 μm (PM2.5)] and increased mortality. Biological evidence has been established for plausible mechanisms between PM2.5 and mortality. Based on evidence from epidemiological and toxicological studies, air quality guidelines or standards were established for PM2.5. This article reviews the recent scientific knowledge and political aspect on health risk due to PM2.5. Many recent epidemiologic studies reported consistent positive associations between short- and long-term exposure to fine particulate matter (PM2.5) and respiratory and cardiovascular effects and mortality. Many key studies reported positive and significant associations for PM2.5 air quality distributions characterized by overall mean concentrations around 8.0 μg/m3, which is below 10.0 μg/m3 of existing World Health Organization air quality guideline. Although the evidence for associations at lower concentrations (i.e., means < 8.0 μg/m3) is more limited, recent studies provided evidence of linear, no-threshold relationships between long-term exposure to PM2.5 and all-cause and cause-specific mortality. For protecting public health, urgent action by health and other sectors to reduce the serious adverse health effects due to PM2.5 is required, based on the precautionary principle.
