Table 3.

Wind and PM 2.5 IV — Confirmed COVID-19 cases .

	(1)	(2)	(3)
Weighted PM 2.5	0.146**	0.128**	0.133**
	(0.0684)	(0.0647)	(0.0659)
F Stat	14.28	14.89	15.13
Dep Var Mean	7.875	7.882	7.882
Pct change mean	1.849	1.627	1.689
Controls	✓	✓	✓
County & State-by-week FEs	✓
County and MSA-by-week FEs		✓
County and CBSA-by-week FEs			✓
Observations	97,885	97,783	97,740

${}^{\ast }$$p<0.1$, ${}^{\ast \ast }$$p<0.05$, ${}^{\ast \ast \ast }$$p<0.01$. Standard errors clustered at the county level in parentheses. Outcomes are daily case incidence per 100,000 population. Controls include state-level and county-level policy adoption, wind speed, minimum and maximum daily temperature, precipitation, prior two-week social distancing behavior, day-of-week, and two lagged wind direction-by-monitor cluster interactions. Displayed output of a two-stage least squares regression model with county and state-by-week, MSA-by-week, or CBSA-by-week fixed effects in which wind direction and air quality monitor cluster interactions are used to predict PM 2.5 levels in a county on a given day. F-statistics of the relevance test are computed assuming first-stage standard errors are not serially correlated.