Background: Air pollution has become a global challenge, and a growing number of studies have suggested possible relationships between long-term exposure to fine particulate matter (PM 2.5 ) and risks of cardiovascular events, specifically, myocardial infarction (MI). However, the recently reported results were inconsistent. We thus performed a meta-analysis and sought to assess whether long-term exposure to PM 2.5 relates with incident MI risks and post-MI mortality. Methods: EMBASE, Web of Science and PubMed were searched for all potentially eligible studies published before August 2, 2020 using a combination of keywords related to PM 2.5 exposure, its long-term effects and myocardial infarction. Key information was extracted, and calculated hazard ratio (HR) values were combined by selecting corresponding models according to heterogeneity test. A sensitivity analysis and a publication bias assessment were also performed to determine the reliability of the results. Results: Of the initially identified 2100 citations, 12 studies met our inclusion criteria and observed a total population of approximately 7.2 million. Pooled estimates (per 10 m g/m 3 increase) indicated a statistically significant association between long-term PM 2.5 exposure and MI incidence (HR ¼ 1.10, 95% CI: 1.02e1.18) or post-MI mortality (HR ¼ 1.07, 95% CI: 1.04e1.09). Results for MI incidence from Egger’s linear regression method (P ¼ 0.515) and Begg’s test (P ¼ 0.711) showed no obvious publication bias. Conclusion: Our quantitative analysis reveals a significant link between long-term PM 2.5 exposure and greater MI incidence risks or higher post-MI mortality. Our findings may therefore have implications for individual protection and policy support to improve public health.