Table 1.

Summary Statistics of Population and Exposures

Total Number of Births		8,017,865

PM Gestational Exposures

PM_10-2.5 Gestational Exposure^a	mean (SD)	13.72 μg (5.67)

PM_2.5 Gestational Exposure	mean (SD)	12.87 μg (3.58)

Mother and Infant Characteristics

Birth Weight	mean (SD)	3,394.0 g (467.9)

	37-38 weeks	2,421,380 (30.2%)
Gestational Length	39-40	4,185,847 (52.2%)
	41-44	1,410,638 (17.6%)

	<20 years	841,790 (10.5%)
	20-24	1,976,411 (24.7%)
Maternal Age	25-29	2,175,054 (27.1%)
	30-34	1,884,789 (23.5%)
	35-39	934,974 (11.7%)
	>40	204,847 (2.6%)

	White	6,149,190 (76.7%)
Maternal Race	Black	1,221,968 (15.2%)
	Other	646,707 (8.1%)

	Less than High School	1,980,837 (24.7%)
	High School	2,195,200 (27.4%)
Maternal Educational Attainment	Some College	1,671,202 (20.8%)
	College	2,037,459 (25.4%)
	Unknown	133,167 (1.7%)

Maternal Marital Status	Married	5,050,811 (63.0%)
Maternal Marital Status	Unmarried	2,967,054 (37.0%)

Infant's Sex	Male	4,079,206 (50.9%)
Infant's Sex	Female	3,938,659 (49.1%)

	First Birth	2,749,952 (34.3%)
Parity	Second or Later Birth	5,243,384 (65.4%)
	Unknown	24,529 (0.3%)

	First	6,498,200 (81.0%)
	Second	1,088,782 (13.6%)
Trimester Prenatal Care Begin	Third	227,415 (2.8%)
	Never	71,847 (0.9%)
	Unknown	131,621 (1.6%)

	Yes	489,034 (6.1%)
Tobacco Consumption During Pregnancy	No	5,177,739 (64.6%)
	Unknown	2,351,092 (29.3%)

Alcohol Consumption During Pregnancy	Yes	32,248 (0.4%)
	No	4,154,003 (51.8%)
	Unknown	3,831,614 (47.8%)

SES Levels of Residential County

Less than High School Education (%)	mean (SD)	18.5 % (6.4)

Below Poverty Line (%)	mean (SD)	13.8 % (4.3)

PM_10-2.5 is based on original estimation.