Science Source

Estimating Causal Effects of Long-Term PM2.5 Exposure on Mortality in New Jersey

Estimates the causal effects of long-term PM2.5 effect on mortality and tested the effect modifications by seasonal temperatures, census-tract-level socio-economic variables, and county-level health conditions
Specifically, estimates the association between long-term exposure to PM2.5 and mortality controlling for geographical differences using dummy variables for each census tract in New Jersey, a state-wide time trend using dummy variables for each year from 2004 to 2009, and mean summer and winter temperatures for each tract in each year
Finds—for each interquartile range (2 µg/m3 ) increase in annual PM2.5—there was a 3.0% (95% confidence interval: 0.2, 5.9%) increase in all natural cause mortality for the whole population, with similar results for people older than 65 [3.5% (0.1, 6.9%)] and people 65 or younger [3.1% (-1.8, 8.2%)]
Finds mean summer temperature and mean winter temperature in a census tract significantly modified the effect of long-term exposure to PM2.5 on mortality
Observes a higher percentage increase in mortality associated with PM2.5 in census tracts with more blacks, lower home value, or lower median income
Identifies a causal effect of long-term PM2.5 on mortality which is modified by seasonal temperatures and ecological socio-economic status under the assumption of the difference-in-differences approach