Environmental tobacco smoke (ETS) - the smoke coming from the end of the burning cigarette - is one of the most common sources of carcinogens encountered by the public. Nation-wide, ETS exposures are estimated to cause up to several thousand cases of lung cancer each year. Not much is known about how large these potential exposures to ETS are or which indoor locations might be the most important contri-butors over time. Most of the known carcinogens in ETS are part of the “smoke” or particles produced in the combustion of the cigarette. When inhaled, these particles deposit in the lungs; where they deposit depends upon the size of the particles inhaled.
The research we propose here consists of both laboratory-based experiments and measure-ments made in actual buildings. The laboratory work would focus on three topics. The first is to better understand how the movement of ETS from one room to another would affect the concentrations and sizes of the smoke particles. Although some research has been done on this topic, further work will help improve our understanding of how ETS exposures are affected by being in the same or a different room than the smoker. Because ETS particles are often the same size as other particles found in indoor air, measurements to determine ETS exposures are often difficult or uncertain. We have therefore proposed to examine how well some of the ‘tracer’ chemicals or particles that have been used can predict ETS exposures.
Finally, some research has suggested that some chemicals and possibly particles may be re-emitted from surfaces in rooms where heavy smoking has occurred. Such emissions may constitute an important source of secondary exposures to ETS. We have proposed a set of experiments to investigate this topic further.
After the laboratory-based experiments are completed, we will make measurements in two or three actual buildings to see how the results from the lab experiments compare with measurements made in the real world. In combination, this work is directed toward a better understanding of how exposures to ETS may vary under different conditions of exposure. |
Environmental tobacco smoke (ETS) - - the smoke released from the burning end of the cigarette is one of the most common sources of carcinogens to which the general public is exposed. However, little is known about the size and extent of potential exposures to ETS. The objective of this research project is to improve the basis for estimating ETS exposures in a variety of indoor environments. The research utilized experiments conducted in both laboratory and 'real-world' buildings to 1) study the transport of ETS species from room to room, 2) examine the viability of using various chemical markers as tracers for ETS and 3) evaluate to what extent re emission of ETS components from indoor surfaces might add to the ETS exposure estimates.
A three-room environmental chamber was used to examine multi-zone transport and behavior of ETS and its tracers. One room (simulating a smoker's living room) was extensively conditioned with ETS, while a corridor and a second room (simulating a child's bedroom) remained smoke-free. As reported last year, a series of 5 sets of replicate experiments were conducted to simulate the movement of ETS between rooms under different door opening and flow configurations: sealed, leaky, slightly ajar, wide open, and under forced air-flow conditions. When the doors between the rooms were slightly ajar the particles dispersed from the smoking room into the other rooms, eventually reaching the same concentration. Four chemical tracers were examined: ultraviolet-absorbing particulate matter. (UVPM), fluorescent particulate matter (FPM), nicotine and solanesol. Both (UVPM) and (FPM) traced the transport of ETS particles into the non-smoking areas. Nicotine, on the other hand, quickly adsorbed on unconditioned chamber, surfaces so that nicotine concentrations in these rooms remained very low, even during smoking episodes. These findings suggest that using nicotine as a tracer of ETS particle concentrations may yield misleading concentration and/or exposure estimates. The results of the solanesol analyses were compromised, apparently by exposure to light during collection (lights in the chambers were always on during the experiments). This may mean that the use of solanesol as a tracer is impractical in 'real-world' conditions.
As part of the final year of this project we conducted measurements of ETS particles and tracers in three residences occupied by smokers who have joined a smoking cessation program. This part of the study was designed as a pilot study, preparatory for a larger study to be conducted in multiple homes. Our objective was to improve our understanding of how ETS aerosols are transported (and thus, whether limiting smoking to certain areas of buildings has an effect on ETS exposures in other parts of the building). As with the chamber studies, we wanted to examine whether measurements of various chemical tracers, such as nicotine, solanesol, FPM and UVPM, can be used to accurately predict ETS concentrations and potential exposures in 'real-world' settings, as has been suggested by several authors. The ultimate goal of these efforts, and a larger multiple house study, is to improve the basis for estimating ETS exposures to the general public.
Because - we only studied three houses conclusions - an effort designed to test our field measurement methods and protocols no firm can be developed from our data. However, the results for the ETS tracers are essentially the same as those we observed in the chamber experiments, that is, the use of nicotine is problematic with respect to its accuracy as a marker for ETS exposure. In the smoking areas of the homes, nicotine appeared to be a suitable indicator; however in the non-smoking regions, nicotine behavior was very inconsistent. The other tracers, UVPM and FPM, provided a better basis for estimating ETS exposures in the 'real world'. The use of solanesol was compromised - - as it had been in the chamber experiments by exposure to light during collection. |