Carbon monoxide in exhaled air of students in Tehran

Carbon monoxide poisoning is a major cause of mortality due to gasinhalation. It is more prevalent in winter, because of poor indoor ventilation. The purpose of our study was to evaluate exhaled carbon monoxide of students and to estimate their exposure to this gas.

This cross-sectional study was performed in winter 2008. The exhaled carbon monoxide level of 184 students was assessed by breath analyzer. Questionnaire data were collected to assess smoking habit, types of domestic exposures and symptoms of carbon monoxide intoxication.

Students consists of 79 boys and 105 girls. Number of cases in carbon monoxide levelsof 0-6 ppm, 7-10ppm, 11-20ppm and above 20ppm were consecutively 150(81.52%),23(12.50%), 10(5.43%) and 1(0.54%). The difference of symptoms in different groups was not significant.

Due to our results, 34(18.47%) cases of healthy nonsmoker students had abnormal exhaled carbon monoxide level of more than 1-3 ppm which could be attributed to environmental exposures. 11(5.97%) cases had carbon monoxide exhaled level of more than 11ppm which exceeds the permissible exposure limits. More attention should be paid to the sources of carbon monoxide exposure in children, in order to minimize morbidity and mortality related to carbon monoxide intoxication.