Table 6. Risk of emergency department visits for STEMI associated with each 10 µg/m³ increase in PM_2.5 concentration in the previous 24 h stratified by age, sex, season, and comorbid conditions.

Characteristic		OR (95% CI)	P-Value for interaction
Age, years	<65	0.97 (0.90–1.05)	0.04*
	≥65	1.15 (1.08–1.23)
Sex	Male	1.08 (1.02–1.15)	0.68
	Female	1.01 (0.93–1.09)
Season	Winter	1.06 (0.99–1.14)	0.85
	Summer	1.03 (0.96–1.10)
Diabetes	Yes	1.02 (0.94–1.11)	0.85
	No	1.06 (1.00–1.13)
Hypertension	Yes	1.10 (1.03–1.17)	0.49
	No	1.01 (0.93–1.08)
Smoking	Yes	1.08 (1.01–1.15)	0.77
	No	1.03 (0.95–1.10)

STEMI, ST-elevation myocardial infarction.

*P < 0.05, adjusted for temperature and relative humidity.