Short-term exposure to air pollution and mental disorders: a case-crossover study in New York City

Abstract Background: There is growing evidence suggesting that exposure to air pollutants is associated with mental disorders. We aimed to investigate the impact of short-term exposures to both fine particulate matter (PM2.5) and ozone (O3) assessed at fine spatiotemporal resolutions on emergency room (ER) visits related to mental disorders using 475,755 records from New York City between 2010 and 2016. Method: We assessed the short-term impact of daily air pollution exposures on ER visits related to mental disorders using a case-crossover design with a conditional logistic regression. We further tested whether the impact of PM2.5 and O3 varied by individuals’ age, sex, and race/ethnicity, and if the associations were modified by the degree of visibility of greenspace at individuals’ residence. Results: The results suggested that the relative risk of visiting ER for mental-disorders increased by 2.78% (95% CI: 1.82% – 3.76%) with a 10 μg/m3 increase in ambient PM2.5 concentration over a 4 day moving average (lag 0-3 days) and increased by 0.71% (95% CI: 0.28% – 1.15%) with a 10 ppb increase in O3 concentration on a single day lag (lag 1 day), and these effects were modified by age and race/ethnicity, but not by sex or surrounding greenery. Specifically, we found that age group 19 - 35 years old and non-Whites were more susceptible to the effects of ambient air pollution exposures. In terms of specific disorders, we found that both PM2.5 and O3 have an effect on ER visits for psychotic disorders, but not dementia. Conclusions: Our findings suggest that there is a positive association between short-term exposure to ambient air pollution increased ER visits for mental disorders. Further research is needed to determine the underlying mechanisms by which exposure to PM2.5 and O3 is linked to ER visits for mental disorders.