Short-Term Exposure to Air Pollution Associated with an Increased Risk of ST-Elevation and Non-ST-Elevation Myocardial Infarction Hospital Admissions: A Case-Crossover Study from Beijing (2013–2019), China

While air pollution is known as a risk factor for acute myocardial infarction (AMI) incidence, its impact on AMI subtypes—ST-elevation (STEMI) and non-ST-elevation myocardial infarction (NSTEMI)—remains incompletely understood. This study analyzed 149,632 AMI hospital admissions (70,730 STEMI and 69,594 NSTEM) in Beijing, China, from 2013 to 2019 using a time-stratified case-crossover design to evaluate the association between daily concentrations of six air pollutants (PM2.5, PM10, SO2, NO2, CO, and O3) and daily hospital admissions for total AMI, STEMI, and NSTEMI. Elevated levels of PM2.5, PM10, SO2, NO2, and CO were significantly associated with increased admission risk for total AMI, STEMI, and NSTEMI, with the strongest lag effects observed at lag0 for STEMI and at lag1 for NSTEMI. Subgroup analyses showed enhanced effects of PM2.5, SO2, and NO2 for total AMI and SO2 for NSTEMI among individuals with asthma. Additionally, a stronger effect of PM10 on STEMI was observed among individuals with stroke. These findings demonstrate that air pollutants differentially impact AMI subtypes through distinct temporal patterns and population vulnerabilities, underscoring the necessity of incorporating AMI subtype classification and individual susceptibility factors in environmental health risk assessments and related public health policies.