Table 14.

IV estimates (NO${}_2$, CO, and O${}_3$)

	(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)
	OLS	OLS Pref	OLS	IV	OLS	IV	OLS	IV
WBT	$-$107.325${}^{\ast \ast \ast }$	$-$78.001${}^{\ast \ast \ast }$	$-$74.811${}^{\ast \ast \ast }$	$-$102.847${}^{\ast \ast \ast }$	$-$47.518${}^{\ast \ast \ast }$	$-$141.765${}^{\ast \ast \ast }$	$-$106.236${}^{\ast \ast \ast }$	$-$240.053${}^{\ast \ast \ast }$
	(13.992)	(9.869)	(12.217)	(14.575)	(13.226)	(25.141)	(12.621)	(60.652)
PM2.5	Yes	No	No	No	No	No	No	No
PM10	Yes	No	No	No	No	No	No	No
SO${}_2$	Yes	No	No	No	No	No	No	No
NO${}_2$	Yes	No	Yes	Yes	No	No	No	No
CO	Yes	No	No	No	Yes	Yes	No	No
O${}_3$	Yes	No	No	No	No	No	Yes	Yes
Obs	24,546	35,190	24,546	24,546	24,546	24,546	24,546	24,546
No. of workers	437	635	437	437	437	437	437	437