Table 2.

Monthly Prenatal Average Ambient Air Pollution Exposure Among Mother-Infant Pairs from the Southern California Mothers Milk Study

Pollutant	Means ± SD of Prenatal Exposure Windows
	Preg 1 m	Preg 2 m	Preg 3 m	Preg 4 m	Preg 5 m	Preg 6 m	Preg 7 m	Preg 8 m	Preg 9 m	Preg 1-9 m
NO2 (ppb)	18.17 ± 6.57	18.26 ± 6.12	17.94 ± 5.39	18.22 ± 6.06	18.06 ± 6.67	17.72 ± 6.42	17.54 ± 6.71	17.45 ± 6.62	17.67 ± 6.66	17.89 ± 2.43
PM10 (µg/m3)	28.37 ± 5.67	29.18 ± 6.24	28.99 ± 5.94	29.38 ± 6.34	30.21 ± 6.79	29.84 ± 6.55	30.29 ± 7.43	30.49 ± 7.30	30.91 ± 6.76	29.74 ± 3.94
PM2.5 (µg /m3)	11.86 ± 2.60	11.90 ± 2.39	11.50 ± 2.37	11.55 ± 2.64	12.21 ± 3.79	11.83 ± 2.90	11.94 ± 3.56	12.17 ± 3.72	11.93 ± 2.97	11.88 ± 1.24

Means and standard deviations (SD) of ambient air pollutants during each monthly lag of the 9 months pregnancy (Preg) period. As an example, Preg 1 m = 1^st month of pregnancy