Effects of ambient fine particulate matter on the exacerbation of psychiatric disorders in southern Taiwan: a case-crossover study

This study investigated the impact of short-term exposures to ambient fine particulate matter 2.5 (PM_2.5) on the exacerbation of psychiatric disorders (PDs) in southern Taiwan between 2014 and 2020. Data on emergency room visits (ERVs) for PDs and air pollutant levels were obtained from the Chang Gung Research Database and the Environmental Protection Administration, respectively. A time-stratified case-crossover design was adopted to estimate the risks of ERVs for PDs. At lag4 days, a 10-μg/m³ increase in PM_2.5 was associated with significant increases in ERVs in both single- and multi-pollutant models, with odds ratio (OR) of 1.18 [95% confidence interval (95% CI): 1.00, 1.38] (PM_2.5), 1.20 (95% CI: 1.00, 1.43) (PM_2.5 + SO₂), 1.23 (95% CI: 1.03, 1.46) (PM_2.5 + O₃), and 1.25 (95% CI: 1.03, 1.52) (PM_2.5 + SO₂ + O₃). For cumulative lags (lag0-6), a 10-μg/m³ increase in PM_2.5 was associated with significant increases in ERVs only for multi-pollutant model (PM_2.5 + SO₂), with OR of 1.41 (95% CI: 1.03, 1.93). Among males, significant increases in ERVs were observed at lag4 and lag0-6 days; however, no significant associations were observed in females. In conclusion, short-term exposure to PM_2.5 increased the risk of PDs exacerbation, exhibiting both delayed and cumulative effects, with male patients found to be more sensitive.