Assessing Adverse Health Effects of Long-Term Exposure to Low Levels of Ambient Air Pollution: Phase 1

Research Report 200,

Research Report 200 describes the first-phase results of a study led by Dr. Francesca Dominici of the Harvard T.H. Chan School of Public Health and presents the detailed Commentary by HEI’s Low-Exposure Epidemiology Studies Review Panel on the results and the needs for further analysis.

The study evaluates the relationship between exposure to low concentrations of PM2.5 and O­3 and all-cause mortality. The team developed high resolution (1 km2) ambient concentration prediction models by combining data from a variety of sources, including satellite measurements and ground-based monitors. Health data were based on records of 61 million Medicare enrollees, between the years 2000 to 2012, which they analyzed using cohort and case crossover designs.

HEI published the Phase 2 (final) report in 2022.

Data underlying this Phase 1 report by Dominici and colleagues are available at this time. For access to the exposure data, see Health data can be obtained from Medicare. For the statistical code, see