Background Although particulate matter, with diameters 2.5) and 10), and other pollutants have been associated with cardiovascular morbidity and mortality, the effect of pollutants on acute myocardial infarctions (AMIs) has rarely been investigated in Asia, especially in Shanghai, China. Methods Between 1 November 2013 and 27 April 2014, 972 patients from the Pudong District, Shanghai City, were assessed by the Emergency Medical Service. A case-crossover design was used to analyze exposure to air pollution and the AMI risk. Exposures to PM2.5, PM10, nitrogen dioxide (NO2), sulphurdioxide (SO2), and carbon monoxide (CO) were based on the mean urban background levels. The associations among AMI admissions, the included pollutants, temperature, and relative humidity were analyzed using correlation and logistic regression. Results The urban background levels of PM2.5, PM10 and CO were associated with an increased risk of AMI, unlike NO2 and SO2 levels. The OR (95% CI) for AMI were 1.16 (1.03–1.29), 1.05 (1.01–1.16), 0.82 (0.75–1.02), 0.87 (0.63–1.95), and 1.08 (1.02-1.21) for PM2.5, PM10, NO2, SO2, and CO, respectively. Increases in the air quality index (AQI) were associated with more AMI occurrences. There was no correlation between fluctuations in temperature and relative humidity with AMI hospital admissions. Conclusions Short-term exposure to moderate-serious pollution levels is associated with increased risk of AMI. Increased PM2.5, PM10 and CO levels are related to increased AMI admissions.