Temporal Variations of Particulate Air Pollution: A Marker for Free Radical Dosage and Adverse Health Effects?

Abstract

Statistical associations have been observed between human mortality and fine and sulfate particles. However, significant gaps in our knowledge exist in explaining the observed health effects based on results from controlled exposure studies. It is possible that the causative agent is a species that is correlated with particulate matter, but not measured by routine sampling of atmospheric aerosols. Free radicals, such as hydroxyl radicals, are responsible for the formation of fine and sulfate particles. They are also known to be damaging to lung tissue, as well as playing a role in the pathogenesis of a wide variety of disease states, including inflammation and cancer. These observations suggest that radicals may be at least partly responsible for adverse health effects, and that fine particle mass could serve as a marker for free radical dosage. Applying receptor models to time-series aerosol data to determine the temporal variations of source contributions may provide additional insight regarding mixtures of species that cause a disproportionate fraction of the health effects.