Introduction: Today, air pollution is one of the critical problems in metropolitans and necessary preparations are needed for confronting with this crisis. The present study was based on the goal of determining the relation of air pollutant levels with the rate of emergency admission for respiratory and cardiovascular patients. Methods: In the present retrospective cross- sectional study, all respiratory and cardiovascular patients, referred to emergency department during 2012, was assessed. The meteorological and pollution data were collected. Information of the numbers and dates (month, day) of daily admission of respiratory and cardiovascular diseases was achieved from hospital's electronic registration system. The relation of air pollution and respiratory and cardiovascular admissions were analyzed by Generalize additive model (GAM). Results: Totally 5922 patients were assessed included 4048 (68.36%) cardiovascular and 1874 (31.64%) respiratory disease. Carbon monoxide (CO) level was independent risk factor of cardiovascular disease on the same day (RR=1.49; 95% CI: 1.25- 1.77; P<0.001), the last day (RR=1.22; 95% CI: 1.02- 1.45; P=0.03), and the two last days (RR=1.3; 95% CI: 1.09- 1.54; P<0.001). The same process was similarly repeated for ozone (O3). In addition, the O3 level in the same day (RR=1.49; 95% CI: 1.25- 1.77; P<0.001), the last day (RR=1.22; 95% CI: 1.02- 1.45; P=0.03), the two last days (RR=1.3; 95% CI: 1.09- 1.54; P<0.001), and the last weak (RR=1.004; 95% CI: 1.0007-1.008; P=0.02) were independent risk factors of respiratory admissions. The increased level of particulate matter less than 2.5 micrometers in diameter (PM2.5) like O3 led to grow the admissions in emergency department with respiratory causes. Conclusion: The findings of the present study suggested that rising the levels of CO and O3 during two days leads to a significant increase in cardiovascular admission in the third day. Furthermore, increase the O3, PM2.5, nitrogen oxides (NO2), and CO levels causes to rising respiratory admissions in emergency department
