Figure 3. Exposure–Response Curves for PM_2.5 Exposure and Mortality among Marginalized Subpopulations.

Shown are point estimates (solid lines) and 95% confidence intervals (gray shaded areas) of the hazard ratio for death corresponding to decreases in annual average PM_2.5 exposure (to 6 to 11 μg per cubic meter) with respect to 12 μg per cubic meter on average for subpopulations defined in selected ways. Estimates below 6 μg per cubic meter are not shown in order to focus attention on plausible ranges for PM_2.5 pollution policy. In all panels, curves for Black persons are blue and White persons are orange. Panel A defines persons according to racial identity only without regard to income. Panel B includes only higher-income persons. Panel C includes only low-income persons. Low income was defined as dual eligibility for both Medicare and Medicaid. Confidence intervals were not adjusted for multiplicity; therefore, they should not be used in place of hypothesis testing.