Michelle L. Bell

Professor of Environmental Health


Air Pollution Mixtures

Most air pollution health research focuses on a single pollutant or treats other pollutants as confounders, although in reality we breathe a complex mixture. We explore methods to investigate multi-pollutant systems and estimate health response to simultaneous exposure of multiple pollutants. Although airborne particulate matter constitutes a complex mixture, particles are regulated and largely studied according to total mass, without regard to chemical structure. Policy-makers would benefit from information on which components or sources are most toxic. We identified regional and seasonal variation in health effects for particle mass. We hypothesize that some particles are more toxic than others due to their chemical composition, which exhibits similar spatial and temporal patterns as particulates’ health effects. Our current projects investigate which particle characteristics are most harmful, with respect to size, chemical structure, and source. As an example, we found that particles from vehicles are associated with low birth weight.


Examples From Our Work


PM2.5 sulfate in the United States (Bell et al. Environmental Health Perspectives 2007).


Increase in low birthweight per interquartile range increase in gestational exposure to PM2.5 sources and constituents (Bell et al. Epidemiology 2010).


Selected Relevant Publications

Bell ML, Ebisu K, Peng RD. In press. Community-level spatial heteogeneity of chemical constituent levels of fine particulates and implications for epidemiological research. Journal of Exposure Science and Environmental Epidemiology.

Bell ML, Belanger K, Ebisu K, Gent JF, Lee HJ, Koutrakis P, Leaderer BP (2010). Prenatal exposure to fine particulate matter and birth weight: Variations by particulate constituents and sources. Epidemiology 21(6), p. 884-891.

Dominici F, Peng RD, Barr CD, Bell ML. 2010. Protecting human health from air pollution: Shifting from a single pollutant to a multi-pollutant approach. Epidemiology 21(2), p. 187-194.

Bell ML, Ebisu K, Peng RD, Samet JM, Dominici F. 2009. Hospital admissions and chemical composition of fine particle air pollutionAmerican Journal of Respiratory and Critical Care Medicine 179(2), p. 1115-1120.

Bell ML, Dominici F, Ebisu K, Zeger SL, Samet JM (2007). Spatial and temporal variation in PM2.5 chemical composition in the United States for health effects studies. Environmental Health Perspectives 115(7), p. 989-995.