Carbonmonoxide (CO) is an important component of air pollution caused by traffic exhaust fumes. CO can cause chronic poisoning which shows its first symptoms as headaches, blurry vision, difficulty in concentration, and confusion. With the increasing number of vehicles in metropolitan areas of Turkey, the CO level has also increased in the city air as is the case in the capital city of Ankara, especially at certain locations. As far as the effects of CO on humans are concerned, traffic policemen are the population group under risk due to their inhalation of CO-rich air while on duty at the crowded cross-sections of the city. The traffic policemen on duty at these cross-sections are exposed to these high levels of CO for at least 6 h. This study was performed to investigate the traffic policemen (traffic organizers) who are exposed to high concentrations of CO at crowded cross-sections of Ankara City and to find out if chronic CO intoxication exits among this risk group. The CO levels in the ambient air at these cross-sections have also been compared to, and correlated with measurements of CO in the expired air of the target population. Additional factors like smoking, general health status, type of heating systems used at home, etc., have been taken into consideration by evaluating special questionnaires filled out by the policemen. A control group of clerk policemen, who were not engaged in street traffic activities was formed for comparative purposes. (C) 2000 Academic Press.