UC Merced

Background: Despite the decrease in overall pollution levels across California, the San Joaquin Valley (SJV) remains a non-attainment area for pollutants including PM2.5 and O3. Objectives: We assessed the association between acute exposure to PM2.5 and O3 and the risk of fetal and infant death in the SJV. Methods: This time-stratified case-crossover analysis includes 1,343 singleton fetal deaths and 1,097 singleton infant deaths in the SJV from 2016 to 2019. Daily O3 and PM2.5 data were geospatially linked to the residential zip codes of mothers at delivery. We examined critical exposure windows including the day of death (lag 0) and the 14 days leading up to it (lag 1 - lag 14). We used conditional logistic regression models to calculate the odds ratio (OR) and 95% confidence intervals for each 10-unit increase in pollutants. Results: PM2.5 during cold (November-April) and O3 during warm seasons (May-October) were positively associated with higher odds of fetal and infant deaths. O3 was positively associated with both fetal and infant deaths across all lags while no significant associations were observed between infant death and PM2.5 exposure. Associations also varied across racial, and socio-economic divisions and maternal ages. Conclusions: As climate change escalates, rising air pollution may contribute to perinatal mortality.