The quantitative association between premature mortality and ground-level concentrations
of PM2.5 and ozone is generally assessed through the derivation of relative risk (RR) factors and concentration-response functions (CRFs).
An expert elicitation by the U.S. EPA reports a decrease of 1% (range 0.4%e1.8%) in annual all-cause deaths for a 1 mg m3 decrease in the annual average PM2.5 exposure in the
United States (U.S. EPA, 2011a).
Similar results are reported for Europe (Cooke et al., 2007). Jerrett et al. (2009) associated longterm ozone exposure with the risk of death from respiratory causes.
In that study, the relative risk of early death from respiratory diseases as a consequence of an increase in ozone concentration of 10 ppb is estimated as 1.040 (95% confidence interval, 1.010e1.067).