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

There is growing evidence suggesting that exposure to air pollutants is associated with mental disorders. We investigated 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. We assessed the short-term impact of daily air pollution exposure on ER visits using a case-crossover design with conditional logistic regression. We further tested whether the impact of PM2.5 and O3 varied by individuals’ age, sex, and race/ethnicity, and if associations were modified by the degree of visibility of greenspace at individuals’ residences. Results suggested that the relative risk of visiting an ER for mental-disorders increased by 2.78% (95% CI: 1.82%–3.76%) with a 10 μgm−3 increase in ambient PM2.5 concentration over a 4 day (d) moving average (lag 0–3 d) 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 d), and that 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 exposure. 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. Our findings suggest that short-term exposure to ambient air pollution is associated with 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 these ER visits.