Table 2.

Concentration–response functions.

Exposure	Racial/ethnic group	Hazard ratio (95% CI)	Reference
Linear across all ${\mathrm{PM}}_{2.5}$ levels	All	1.06 (1.04, 1.08)	Krewski et al. 2009
	All	1.073 (1.071, 1.075)	Di et al. 2017
	White American	1.063 (1.060, 1.065)	Di et al. 2017
	Black American	1.208 (1.199, 1.217)	Di et al. 2017
	Asian American	1.096 (1.075, 1.117)	Di et al. 2017
	Hispanic American	1.116 (1.100, 1.133)	Di et al. 2017
	Native American	1.100 (1.060, 1.140)	Di et al. 2017

Note: The reported hazard ratios are for mortality risk associated with $10{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$ increase in ${\mathrm{PM}}_{2.5}$. CI, confidence interval.