Integrating spatiotemporal behavior, indoor-outdoor penetration, and ventilation rates to assess prenatal PM2.5 exposure and the association with birth weight

Previous studies that evaluated the association of PM 2.5 with birth outcomes usually assessed personal exposure as outdoor PM 2.5 concentrations of home address (home-based exposure), overlooking factors such as individual spatiotemporal activities, which may result in exposure error. In a prospective birth cohort conducted in Guangzhou, China during 2017–2020, personal PM 2.5 exposure assessment was updated. We incorporated spatiotemporal activities into the exposure assessment by estimating PM 2.5 exposure for each activity based on its specific location and duration. Additionally, an infiltration factor was applied to estimate indoor-outdoor penetration, and ventilation rates (different age groups and activity levels) were used to better adjust individual exposure levels. Logistic regression and distributed lag non-liner model with Cox proportional hazard model were used to assess the associations of prenatal PM 2.5 exposure with low birth weight (LBW) and small for gestational age at a trimester and weekly level, respectively. Updated personal PM 2.5 exposure was lower than the home-based PM 2.5 . Per interquartile range increase in PM 2.5 during the third trimester was associated with increased risk of LBW, with ORs (95 % CIs) was 2.17 (1.14–4.14) for updated personal exposure and 2.30 (1.17–4.55) for home-based exposure. Updated personal PM 2.5 in the 6th-7th, home-based PM 2.5 in the 5th-7th, and both PM 2.5 exposure in the 35th week later was associated with LBW. Our findings suggest that spatiotemporal activities, indoor-outdoor penetration, ventilation rate should be taken into account of exposure assessment, otherwise PM 2.5 exposure and the association with adverse birth outcomes may be overestimated. • PM 2.5 exposure was updated by space-time behavior, I/O ratio, and ventilation rate. • Updated personal PM 2.5 exposure was lower than the home-based PM 2.5 . • Maternal PM 2.5 exposure was associated with low birth weight in two assessment ways. • The association based on home-based PM 2.5 assessment was stronger.