摘要:Carbon monoxide (CO) is an odorless, colorless and toxic gas that results from incomplete combustion of coal and fossil fuels. The aim of this study was to evaluate cardiovascular mortality (CVM) attributed to CO levels in Ahvaz, Bushehr and Ker-manshah, as the major cities in south western of Iran, with population of 2000000 people during 2013. The measured CO data in 2013 by 10 monitoring stations were used in this study. CO data, temperature and pressure were collected through Ahvaz, Bushehr and Kermanshah Meteorological Organization and Iranian Environmental Protection Agency (EPA). Then, these data were processed by Excel software through correcting temperature and pressure, encode, averaging and filtering. Finally, all data were processed to make input file of Air Q model. The results showed that the maximum and the minimum concentration of CO were associated with Ahvaz and Bushehr with annual averages of 8.51 and 3.76 mg/m3, respectively. This could be due to higher fuel consumption gasoline in vehicles in Ahvaz in comparison with Kermanshah and Bushehr. Cardiovascular mortality during 2013 which was attributed to CO in Ahvaz, Bushehr and Kermanshah were 15, 10 and 3 cases, respectively. The finding of this study showed that maximum and the minimum cases of CVM attributed to carbon monoxide level were estimated 4.3 and 1.4 percent for Ahvaz and Bushehr.