Recent studies indicate that bulk PM mass is not the best surrogate of aerosol health effects, it continues to remain the regulatory parameter. In recent years, certain aerosol properties such as carbonaceous and metallic content, oxidative potential, and surface area have shown better associations with the health effects. New instruments and methods have also been developed to measure these properties. However, the epidemiological and toxicological studies exploring these linkages are sparse and scattered across multiple disciplines, particularly in the Indian subcontinent.

The capability of ambient particulate matter (PM) to generate reactive oxygen species (ROS), conveniently called the oxidative potential is proposed as a better metric for relating the PM pollution with health effects. In this talk, I would present our work on the measurement of oxidative potential of ambient PM from different geographical locations of the world, including United States and India. Essentially, through these measurements and comparisons, we demonstrate the need for developing localized concentration-response functions based on the intrinsic toxicity and chemical composition of the PM. Our current studies in this direction are helping to develop useful insights on the origin of PM toxicity leading to a better assessment of the human health effects of ambient particulate pollution.