Prenatal\nExposure to Source-Specific Fine Particulate\nMatter and Autism Spectrum Disorder

In this study, associations\nbetween prenatal exposure to fine particulate\nmatter (PM2.5) from 9 sources and development of autism spectrum disorder\n(ASD) were assessed in a population-based retrospective pregnancy\ncohort in southern California. The cohort included 318,750 mother–child\nsingleton pairs. ASD cases (<i>N</i> = 4559) were identified\nby ICD codes. Source-specific PM2.5 concentrations were estimated\nfrom a chemical transport model with a 4 × 4 km<sup>2</sup> resolution\nand assigned to maternal pregnancy residential addresses. Cox proportional\nhazard models were used to estimate the hazard ratios (HR) of ASD\ndevelopment for each individual source. We also adjusted for total\nPM2.5 mass and in a separate model for all other sources simultaneously.\nIncreased ASD risk was observed with on-road gasoline (HR [CI]: 1.18\n[1.13, 1.24]), off-road gasoline (1.15 [1.12, 1.19]), off-road diesel\n(1.08 [1.05, 1.10]), food cooking (1.05 [1.02, 1.08]), aircraft (1.04\n[1.01, 1.06]), and natural gas combustion (1.09 [1.06, 1.11]), each\nscaled to standard deviation increases in concentration. On-road gasoline\nand off-road gasoline were robust for other pollutant groups. PM2.5\nemitted from different sources may have different impacts on ASD.\nThe results also identify PM source mixtures for toxicological investigations\nthat may provide evidence for future public health policies.