Table 3—

OLS and IV Estimates of Effect of PM 2.5 on Medicare Hospitalization Outcomes

	FFS all-age mortality	All inpatient spending	Inpatient ER spending	Inpatient admissions rate	Inpatient ER admissions rate	Inpatient + outpatient ER rate	Non-ER admissions rate (placebo)
	(1)	(2)	(3)	(4)	(5)	(6)	(7)
Panel A. OLS estimates
PM 2.5 (μg/m3)	0.130	−11,489	84	−0.717	0.091	0.329	−0.809
	(0.023)	(2,242)	(972)	(0.157)	(0.081)	(0.112)	(0.124)
Dep. var. mean	402	37,984,768	16,805,670	3,366	1,749	3,984	1,617
Effect relative to mean, percent	0.032	−0.030	0.001	−0.021	0.005	0.008	−0.050
Observations	1,898,236	1,898,236	1,898,236	1,898,236	1,898,236	1,898,236	1,898,236
Adjusted R2	0.233	0.511	0.679	0.544	0.694	0.648	0.336
Panel B. IV estimates
PM 2.5 (μg/m3)	0.727	19,339	16,446	2.207	2.060	2.693	0.148
	(0.071)	(9,346)	(4,266)	(0.671)	(0.317)	(0.444)	(0.441)
F-statistic	300	300	300	300	300	300	300
Dep. var. mean	402	37,984,768	16,805,670	3,366	1,749	3,984	1,617
Effect relative to mean, percent	0.181	0.051	0.098	0.066	0.118	0.068	0.009
Observations	1,898,236	1,898,236	1,898,236	1,898,236	1,898,236	1,898,236	1,898,236

Notes: Table reports OLS and IV estimates of equation (1) from the main text. All dependent variables are three-day measures per million fee-for-service (FFS) beneficiaries. All regressions include county, month-by-year, and state-by-month fixed effects; flexible controls for temperatures, precipitation, and wind speed; and two leads of these weather controls. OLS (IV) estimates also include two lags and two leads of PM 2.5 (instruments). Estimates are weighted by the number of FFS beneficiaries. Standard errors, clustered by county, are reported in parentheses.