Researchers from Hasselt University in Dipendeek found exposure to traffic and particulate matter air pollution causes around 12% of MIs.
The study analysed 36 studies that investigated 13 causes of acute MI, including anger, over-eating and stress.
Rather than focusing on the effects of MI triggers on the individual, the research looked at general population data.
Researchers calculated population-attributable fractions (PAFs) using the prevalence and risk associated with each trigger. In doing so, they took into account each risk factor's frequency in the community as well as its strength at the individual level.
Direct exposure to traffic pollution had the highest estimated PAF of the factors assessed in the study. The research showed that it triggered 7.4% of MI cases. General air pollution triggered 4.8% of MIs.
Cocaine was the strongest trigger at the individual level, but had a low frequency in the community.
Commenting on the findings, the researchers said: 'Improvement of the air we breathe is a very relevant target to reduce the incidence of this disease in the general population.'
They said the study was a 'warning against overlooking the public health relevance of risk factors with moderate strength that had high frequency in the community'.