Introduction and aims: Environmental pollution are one of the most relevant risk factors to atherosclerosis. To know awareness about the importance of urban air pollution as a trigger for hospital admission due to acute coronary syndrome (ACS), this study analyzed levels of different gaseous air pollutants in the air and its correlation with number of ACS. Methods: Epidemiological data of patients admitted for ACS in five towns during the years 2006-2008 were recovered. Clinical data regarding admissions for ACS were obtained from the hospital admission services. Measures of seven air contaminants were recovered from the environmental stations. Mixed model including sex, age, location, and the average levels of air pollutants contaminants as fixed effects and its interaction were performed. Results: The incidence rate of ACS is higher in man than woman, and higher in older people than young. The maximum ACS were in the last trimester of the year, was the most elevated levels of gaseous pollutants have been found. Levels of NO2, NO, and CO are positively correlated between them, and negatively correlated with O3 levels. All air pollutants analyzed increase the number of ACS hospital admission in the five locations evaluated. Conclusions: Levels of gaseous pollutants are related between them, being the levels of NO2, NO, and CO, positively correlated, and negatively correlated with levels of O3. Number of ACS hospital admission increases with levels of five air gaseous pollutants studied.