Table 2.

Distribution of exposure to sources of PM_2.5 (μg/m³) by trimester of exposure.

Exposure	1st trimester			2nd trimester			3rd trimester			Whole pregnancy
	25th percentile	50th percentile	75th percentile	25th percentile	50th percentile	75th percentile	25th percentile	50th percentile	75th percentile	25th percentile	50th percentile	75th percentile
Oil combustion	0.63	1.15	1.86	0.61	1.16	1.89	0.53	1.07	1.87	0.77	1.29	1.88
Motor vehicle emissions	2.57	3.54	4.52	2.54	3.46	4.40	2.44	3.41	4.35	2.67	3.52	4.11
Dust	1.12	1.42	1.79	1.16	1.44	1.80	1.16	1.45	1.82	1.23	1.49	1.73
Regional sulfur	2.91	4.12	5.78	2.87	4.06	5.69	2.77	3.97	5.76	3.62	4.26	5.28