Assessment of environmental tobacco smoke and respirable suspended particle exposures for nonsmokers in Prague using personal monitoring

Objective: Exposures to respirable suspended particles (RSP) and environmental tobacco smoke (ETS) were assessed in Prague, Czech Republic, to determine the range and degree of personal exposure by means of personal monitoring over a 24-h period. Design: Self-reported nonsmokers were randomly selected from a representative sample of the population of Prague. Housewives were recruited into one group, primarily for assessment exposures in the home, and office workers were recruited into a second group for assessment of the contribution from the workplace. Methods: A total of 238 randomly selected nonsmoking subjects collected air samples near their breathing zone by wearing personal monitors for 24 h. Samples collected were analyzed for RSP, nicotine, 3-ethenylpyridine, and ETS particles (using ultraviolet absorbance, fluorescence, and solane-sol measurements). Saliva cotinine analyses were also undertaken to confirm the nonsmoking status of the subjects. Results: The most highly exposed subjects in this study were office workers both living and working with smokers. Median time-weighted average: exposure concentrations of 60 mu g m(-3) RSP, 16 mu g m(-3) ETS particles, and 1.6 mu g m(-3) nicotine were determined for these subjects, who also had the highest median saliva cotinine level of 2.4 ng ml(-1) Housewives living in nonsmoking households were the least exposed subjects in this study, showing levels of 32 mu g m(-3) RSP, 0.17 mu g m(-3) ETS particles, and 0.15 mu g m(-3) nicotine. As based upon median levels of ETS particles and nicotine, no group would potentially inhale or be exposed to more than 10 cigarette equivalents per year (CE/y) and the least exposed would inhale less than 1 CE/y. The most highly exposed (90th percentile levels) nonsmokers in this study, who both worked and lived with smokers, would potentially inhale up to 29 CE/y. Overall, the workplace was estimated to contribute between 45% and 49% of the annual exposure to nicotine and ETS particles, respectively. On the basis of determined saliva cotinine concentrations, a misclassification rate of between 1.7% and 2.5% was calculated. Conclusions: Highest exposures were apparent for office workers both working and living in smoking environments, and our findings suggest a significant contribution to overall ETS particle and nicotine levels from the workplace where smoking takes place. Overall, the rates at which subjects were determined to have misclassified their smoking status in this study were the lowest observed in any of the European cities investigated to date. Clearly, a more sensitive method of analysis for cotinine in body fluids is needed for more accurate determination of the levels expected for nonsmokers.