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EDUCATION, AND WELFARE. Health Aspects of Smoking in Transportation Aircraft U.S. Department of Health, Education, and Welfare, National Institute for Occupational Safety and Health, December fl&MAiES AND TABLES FOR CHAPTER 6 I ~ ~ 7 7 (p C 00 N CD G7

I FIGURES AND TABLES, CHAPTER 6 ~ 78 .I m O m tJ CD cn

mainstream smoke. A ratio of greater than 1.0 means the constituent is found in higher concentrations in sidestream smoke than mainstream smoke. A number of the constituents listed are carcinogens or suspected carcinogens according to the International Agency for Research on Cancer. I Measurement of ETS The large number of constituents in ETS make it impossible to assess overall exposure based on measurement of each one. Instead most researchers have measured one or more compounds and have used those to estimate the total exposure to ETS. Changes in ETS composition over time and exposure conditions limit the accuracy of this method. This chapter will discuss in detail only a few of the possible measures of ETS: particles, nicotine, cadmium and nitrosamine. Most of the data presented will be from studies involving cigarette smoke since this is a major source of indoor ETS. Little work has been done on pipe or cigar smoke. Exposures to Environmental Tobacco Smoke According to the U.S. Department of Commerce (1985) about 30% of adults in the U.S. are smokers. 404 of homes nationwide have at least one smoker. In a survey of over 10,000 children in six U.S. cities, the percentage of children living with one or more smoking adults varied from a low of 604 to a high of 75% (Ferris et al,. 1979). Lebowitz and Burrows (1976) reported 544 of children in a study in Tucson had at least one smoker in the home. These data indicate that the potential for exposure to ETS in the home is greater than that inferred from national statistics. Smoking between different demographic groups can vary widely and this will modify the exposure of nonsmokers to ETS. Overall ETS exposure will depend on the proximity of an individual to the source of smoke. Patterns of smoking will be influenced by time, location and type of activity. MICROENVIRONMENTAL MEASUREMENTS OF CONCENTRATIONS Concentrations of Particles and ETS Numerous studies have been conducted using respirable suspended particulates (RSP) as markers for ETS. Both continuous and integrated measurements methods have been used. Although RSP is not specific for the presence of smokers in the home and other indoor locations, the.number of cigarettes smoked have shown to correlate well with RSP. Particulate Concentrations in Homes m 68 GD O m N ~ ~

ae. es. in he:1b. p. Wr iw Jr /y 7o.0a ~ . Da J.n i.e. Yr- y. 1.H Nn nn FIGURE 3. Monthly Mean Mass Respirable Particulate Concentrations (µg/m') Across Siz Cities Source: Spengler at al. (1981)

FIGURE 4. Aerosol Mass Concentration in R & D Office Source: Quant at a1. (1982)

the lungs. Particles greater than 2.5 um in diameter, or coarse particles, are usually formed by mechanical processes like grinding, crushing and abrasion. At least 75% of the silicon, calcium and iron, elements commonly found in soil, appear in this size fraction (Dzubay and Stevens, 1975). Particles from 2.5-10 um can be inhaled and can become deposited in the tracheobronchial regions. Environmental Tobacco Smoke Environmental tobacco smoke (ETS) is a mixture of exhaled mainstream smoke and sidestream.smoke. Sidestream smoke is the smoke that is formed by smoldering between puffs, of a tobacco product and is the major source of ETS. The complex mixture that the smoker inhales with each puff of a cigarette, cigar or pipe is called mainstream smoke. The portion of mainstream smoke that the smoker inhales with each puff of a cigarette, cigar, or pipe is called mainstream smoke. The portion of mainstream smoke that the smoker exhales and the small amount of vapor diffusing through the wrapping of the cigar or cigarette add little to ETS. ETS consists of fresh and aged sidestream and mainstream smoke. The particle sizes which make up ETS vary due to coagulation (the process where two or more particles collide and combine to form a larger particle), evaporation, and the adhesion of particles to surfaces. The size distribution of particles is also affected by air dilution, relative humidity and temperature. Under controlled conditions, several researchers have measured the particle size distribution of sidestream smoke (Keith and Derrick, 1960; Porstendorger and Schraub, 1972; Hiller et al., 1982: Leaderer et al., 1984, Ingebrethsen and Sears, 1986). Based on these studies, the mass median diameter of sidestream smoke can be estimated to be between 0.2 um and 0.4 um. The mass median diameter is the diameter which divides the mass distribution in half, ie: one half of the mass is contributed by particles larger than this diameter and one half by particles smaller. Composition of ETS Environmental tobacco smoke is made up of several thousand different chemical compounds. These compounds may be in the gaseous or solid phase or both. The chemical composition of sidestream smoke differs from that of mainstream smoke. Over 2,000 compounds have been measured in sidestream and mainstream smoke. Some of the constituents in the mainstream smoke of nonfilter cigarettes are listed in Table 3. Also given are ratios of these substances in sidestream smoke compared to 67

b 30 A 10 0 0 0 14 it 14 m w.a..en FIGURE 1. -Time Location Patterns for 46 Infanta Source: Harlos et al. (1987) m 20 n 24 ~ ~ m O m t~., 0

et al. (1987). The rest of their time is usually spent in the livingroom, kitchen or in travel as illustrated in Figure 1. There are some problems with determining total exposure based on time-activity patterns. It is not clear how well individual activity allocation can be generalized from overall population estimates or how concentration levels are affected by varying time and activity patterns. There also may be differences between rooms within microenvironments but this is not well understood. Lebret (1985) examined the respirable suspended particulate (RSP) levels in rooms while participants were smoking or within one half hour of smoking. He found significant variation between the livingroom kitchen and bedroom. Ju and Spengler (1981), who studied 24-hour average concentrations of respirable particulates, also found statistically significant variation between some rooms although the absolute differences were relatively small. Monitoring There are a number of different instruments available to monitor air pollutants. Often the type of instrument used depends on the exposure of interest. Immediate exposures are most important when studying irritant and acute allergic responses. For this type of exposure, instruments which take short term or instantaneous readings are often used: the piezobalance or nephelometer are both used to measure particulates, the ecolyzer is used to measure carbon monoxide. One advantage to these types of instruments is their ability to detect peak pollutant levels. . For acute effects such a upper or lower respiratory infections, the exposures of interest range from hours to days. For increased prevalence of even a lifetime. To measure these exposures, integrated or time-averaging methods are used. These methods include filters which are used to collect particles over long time periods. EXPOSURE TO AIRBORNE PARTICLES Size Distribution and Composition of Particulates The distribution of particulates is essentially trimodal with peak diameters at approximately 0.02 um, 0.5 um and 10 um as shown in Figure 2. The fine particle fraction, or <2.5 um, is produced by condensation. At least 75% of the sulfur, zinc, bromide and lead are found in this size range (Dzubay and Stevens, 1975). Particles <2.5 um are very important for health reasons since these particles can reach the alveolar regions on 66

et al. (1987) considered cadmium as a useful tracer for ETS. They monitored twenty homes and one outdoor site for fine particulates in Watertown, MA. Particles were analyzed for elemental composition using x-ray fluorescence. At the outdoor site and in homes without smokers, cadmium levels were below the detectable limit. Indoor cadmium levels were below the detectable limit. Indoor cadmium levels were highly correlated with indoor fine particulate measurements. Nitrosamines, some of which have been listed as animal carcinogens by the International Agency for Research on Cencer, have been studied in public facilities and homes (Brunnemann et al., 1978). Using continuous measurements they found mean levels of nitrosamines in public facilities which ranged from 0.01 to 0.24 ng/L. Both homes monitored had levels of less than 0.0005 ng/L. Wallace et al. (1987) measured the personal exposure and breath levels of benzene and other aromatics in 200 smokers and 322 nonsmokers in New Jersey and California. Benzene is listed as a human carcinogen by the IARC (1986). They found a significant increase in breath concentration with the number of cigarettes smoked. Smokers were found to have up to 10 times the breath concentration of benzene compared to nonsmokers. Nonsmokers who reported smoke exposure at work showed elevated levels for fall and winter but not for spring and summer. The authors concluded that cigarettes were the major source of benzene for about 50 million U.S. smokers. No single constituent of ETS is sufficient to completely characterize an individuals exposure to ETS. Research on ways to relate these measurements to specific health effects continues to be done. The most prudent course is to measure several of these components in exposure studies. Markers specific to the class of ETS components, or health outcome of interest could be utilized in epidemiologic studies to enhance precision of the exposure. Personal Exposures. Personal monitoring studies have many of the same problems that area monitoring has such as trying to measure ETS exposure based on one or more markers. However, personal exposure monitoring has the advantage of including spatial and temporal dimensions to the measurements. It is also possible to use time activity diaries to link exposure with location and activity. The results of a personal monitoring study by McCarthy et al. (1987) show that the exposure of children to RSP was much higher than that of children from nonsmoking households. The average personal RSP value increased from 29 µg/m3 for children from nonsmoking families to 56 µg/m3 for children from smoking families. The average personal nicotine concentration increased 71

CHAPTER 6 EXPOSURES TO AIR POLLUTANTS John McCarthy, Elizabeth Miesner, John Spengler Harvard School of Public Health Boston, Massachusetts I Microenvironments Concentrations of air pollutants can and do vary depending on location. outdoor pollutant levels may differ from indoor levels. Different indoor locations like homes, schools or workplace can also register varying pollutant levels. An individual's total exposure to air pollutants therefore depends on the time spent in each of these microenvironments and the various concentrations of air pollutants. Time Activity Patterns The amount of time a person spends in different microenvironments is influenced by age, sex, occupation, social class and season. Letz et al. (1984) studied the time-activity patterns of 332 residents of Roane county, Tennessee. The results of study showed that these individuals spent 75% of their time in the home. This was higher (84.9%) for housewives, unemployed and retired persons. The group.spent 10.8% of the time at work with occupational groups working between 21-24% of their time. Of the remaining time: 8.5% was spent in public places, 9% in travel and 2.8% in various other locations. Quakenboss et al. (1982) studied the time allocation for 66 family members from 19 homes in Portage, WI. Individuals were put into one of five general subgroups which are shown in Table 1. Despite wide variations, each group spent most of the time at home. For all participants. total time spent indoors was 853. More recently, Quakenboss and his colleagues analyzed time activity data for over 300 individuals in the Portage, WI area. Participants were categorized into three groups: workers, nonworkers, and students. Activity data were collected from both summer and winter seasons and are summarized in Table 2. Again all groups spent the largest percentage of their time in the home. Time spent outdoors decreased from summer to winter. Infants, because they are essentially immobile, spend most of their time in the bedroom according to a recent study by Harlos 65