摘要:Nitrogen oxides (NO
x), especially nitrogen dioxide (NO
2), are among the most hazardous forms of air pollution. Tobacco smoke is a main indoor source of NO
x, but little information is available about their concentrations in second-hand smoke (SHS), particularly in small indoors. This study presents data of NO
x and its main components nitric oxide (NO) and NO
2 in SHS emitted by ten different cigarette brands measured in a closed test chamber with a volume of 2.88 m
3, similar to the volume of vehicle cabins. The results show substantial increases in NO
x concentrations when smoking only one cigarette. The NO
2 mean concentrations ranged between 105 and 293 µg/m
3, the NO
2 peak concentrations between 126 and 357 µg/m
3. That means the one-hour mean guideline of 200 µg/m
3 for NO
2 of the World Health Organization was exceeded up to 47%, respectively 79%. The measured NO
2 values show positive correlations with the values for tar, nicotine, and carbon monoxide stated by the cigarette manufacturers. This study provides NO
2 concentrations in SHS at health hazard levels. These data give rise to the necessity of health authorities’ measures to inform about and caution against NO
x exposure by smoking in indoor rooms.