Background and Aim: Motor vehicles are an absolute necessity used extensively in all countries of the world. They are a major cause of air pollution with highly undesirable consequences. Thus, exposure to traffic pollution is a growing public health concern. Several studies indicate that people in the cabin of a vehicle inhale air with high concentrations of pollutants such as nitrogen oxides(NOx), particulate matter (PM), volatile compounds (VOCs) and carbon monoxide (CO).

  Materials and Methods: Eexposure of drivers inside motor vehicles to CO was assessed during one year in Tehran, Iran. For this purpose, the concentration of CO was measured in the breathing zone of 72 male taxi drivers using a portable real-time instrument equipped with electrochemical sensors. In addition, records of fixed air pollution monitoring stations in Tehran were examined and the CO concentration in those records were compared with those measured in the taxis.

  Results: The mean in-vehicle CO concentration was 19.91 ± 4.37ppm, while records of fixed air pollution monitoring stations showed the concentration of this pollutant in the air to be 3.69 ± 1.03ppm.

  Conclusion: It can be concluded that factors such as traffic density, weather conditions and vehicles lifespan affect the extent of exposure of taxi drivers to carbon monoxide.