Table 4 -.

The Results of Two-Stage Least-Square Instrumental-Variable Regressions of Pollution on Birth Outcomes

Pollutant	Outcomes
	Birth Weight	Low Birth Weight	Very Low Birth Weight	Full-Term Birth Weight	Foetal Growth	Gestational Weeks	Very Premature Birth
	(1)	(2)	(3)	(4)	(5)	(6)	(7)
Ozone
Ozone (STD)	−20.09637***	.00409**	.00114**	−14.57308***	−.39178***	−.06353*	.00077*
	(6.31102)	(.00163)	(.00046)	(5.5523)	(.11123)	(.03577)	(.00041)
Observations	535,036	535,036	535,036	532,693	535,036	535,036	535,036
R-squared	.08273	.05176	.0263	.05317	.06441	.04515	.02205
Mean DV	3309.772	0.064	0.012	3389.140	85.260	38.814	0.006
%Change	−0.607	6.383	9.527	−0.430	−0.460	−0.164	12.819
F-Stat	63.970	75.439	162.420	56.815	66.054	74.664	136.850
PM 10
PM10 (STD)	−19.49962***	.00378**	.00129***	−12.59806**	−.2778**	−.10734***	.00129***
	(6.32009)	(.00159)	(.00046)	(5.74615)	(.11034)	(.03613)	(.00045)
Observations	392,417	392,417	392,417	390,266	392,417	392,417	392,417
R-squared	.10884	.06797	.0328	.07145	.08856	.04286	.02577
Mean DV	3312.433	0.064	0.012	3391.491	85.278	38.837	0.006
%Change	−0.589	5.911	10.721	−0.371	−0.326	−0.276	21.568
F-Stat	64.941	65.865	158.921	52.106	60.370	64.321	124.001

Notes. Standard errors, clustered at the county level, are in parentheses. The regressions include mother’s race dummy, child gender dummy, county-bymonth fixed effects, and year-by-month fixed effects. The regressions also include average county-level parental controls including mother education (five categories), mother age, father race being White, father’s ethnicity, smoker mothers, father age (10 categories), and prenatal visits. All regressions contain controls for county-level temperature and humidity. The regressions are weighted using the total number of births in each cell.

^***p<0.01,

^**p<0.05,

^*p<0.1