Environmental tobacco smoke and respirable suspended particle exposures for non-smokers in Beijing

The study was centred in Beijing, People's Republic of China, and comprised housewives in one group, primarily for assessing exposures in the home, and office workers in a second group to assess the contribution of the workplace to overall exposure. Two hundred and fifty-three randomly selected non-smoking subjects collected air samples near to their breathing zone by wearing personal monitors for 24 h. Samples collected were analysed for respirable suspended particles (RSP), nicotine, 3-ethenylpyridine and environmental tobacco smoke (ETS) particles using ultraviolet absorbing particulate matter (UVPM), fluorescing particulate matter (FPM) and solanesol-related particulate matter (SolPM) measurements. Saliva cotinine analyses were also undertaken to confirm the non-smoking status of the subjects, and a misclassification rate of between 3.4 and 3.8% was estimated. RSP levels were the highest reported to date by these authors, with median 24-hour time-weighted average concentrations varying between 70 mu g.m(-3) for housewives living in nonsmoking households and 114 mu g.m(-3) for office workers both living and working in smoking environments. High background levels of unidentified airborne fluorescing compounds in Beijing resulted in abnormally high FPM estimates and precluded the use of this marker in the assessment of ETS exposure. The highest exposures to ETS particles (SolPM) and nicotine were estimated for office workers living and working in smoking environments. These subjects would potentially inhale between 5 and 11 cigarette equivalents per year (CEs/y), based upon median exposures, with the workplace contributing approximately 40% of this exposure. The most highly exposed subjects in this study, based upon 90th percentile exposures, would potentially inhale between 32 and 46 CEs/y.