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REVIEW Health Effects of Passive Smoking: Assessment of Lung Cancer in Adults and Respiratory Disorders in Children EPA 600/6-90/006A Salvatore R. DiNardi, Ph.D. September 1990 I have been asked by The Tobacco Institute to comment on the EPA draft report "Health Effects of Passive Smoking: Assessment of Lung Cancer in Adults and Respiratory Disorders in Children" (EPA 600/6-90/006A) (EPA Draft Report). My academic background and experience with indoor air quality problems are summarized below. In 1970, after receiving a Ph.D. in Physical Chemistry from the University of Massachusetts at Amherst, I became an Associate Professor of Industrial Hygiene at that institution, where I continue to teach. The courses that I taught included Principles of Industrial Ventilation, Principles of Occupational Health, Quantitative Methods in Environmental Health, Industrial Hygiene Laboratory and Aerosol Science.

- 2 - I currently serve as the Scientific Director for PHRA, Incorporated, where I design and implement indoor air quality surveys to recognize, evaluate and control the sources of building-related illness in the nonindustrial workplace. I also provide consulting services with regard to ventilation design and indoor air quality training for AT&T, Eastman Kodak, Northeast Utilities, W.R. Grace, Digital Equipment Corporation, Dupont, IBM, ITT, and American Cyanamid, and I am a continuing education consultant in ventilation design, industrial hygiene and indoor air quality for the University of North Carolina at Chapel Hill, George Washington University, and the University of Massachusetts at Amherst. I am a member of the American Industrial Hygiene Association (AIHA), National Environmental Health Association, the American Society of Heating, Refrigerating and Air-Conditioning Engineers, and the American Society for Testing and Materials. For five years I was on the Board of Directors of the New England Section of the Air Pollution Control Association (now the Air and Waste Management Association). I have published more than 40 articles in journals of environmental health, industrial hygiene and chemistry. COMMENTS ON THE DRAFT EPA REPORT The Draft Report's Executive Summary implies that the sole indicator of environmental tobacco smoke (ETS)

3 exposure is the presence of nicotine in air samples or nicotine and cotinine in bioassay: "The ubiquity of ETS and its absorption by members of the general population have been well documented by air sampling and by bioassays for nicotine and cotinine." (page 1-2). The fundamental principles of exposure assessment require that air sampling and bioassays be performed on the chemicals that may be causing an adverse health affect, rather than on chemicals that are poor surrogates for the agent of concern (Goodfellow, 1989; Leaderer, 1990). The complex chemistry of the particle-to-vapor transition of nicotine (and its biological metabolite cotinine) renders uncertain the use of nicotine and cotinine as indicators of exposure to ETS. Nicotine in ETS begins as a particle (aerosol) and converts the vapor phase in indoor air (Eudy, 1986). Exposure to nicotine in the vapor state is not likely to have the same biological effect as exposure to nicotine in the particle to phase. Neither nicotine nor cotinine is a known or suspected carcinogen. Thus, using these substances as surrogates for ETS violates a basic tenet of exposure assessment (Goodfellow, 1989; Leaderer, 1990). It is not scientifically prudent for EPA to build upon this uncertainty and conclude that merely because nicotine exposure occurs, this exposure leads to a measurable adverse health outcome (e.g., lung cancer in nonsmoking wives).

- 4 - The authors also state in the Executive Summary that the total weight of evidence with respect to ETS is based on six main conclusions. Those conclusions that depend on precise, accurate and appropriate exposure assessment are repeated here with my commentary. 1. "Biological plausibility. ETS is taken up by the lungs and distributed throughout the body. The similarity of carcinogens identified in SS and MS along with the established causal relationship between lung cancer and smoking make it reasonable to suspect that ETS is also a carcinogen." (page 1-3). This statement assumes that the sole indicators of ETS exposure are nicotine and cotinine. As noted above, a health assessment cannot legitimately be based on inappropriate exposure assessment. There is little disagreement that MS and SS contain measurable amounts of many compounds, including some that -- albeit in far higher concentrations than are found in ETS -- are considered to be either carcinogens or suspected carcinogens (Eatough, 1990). ETS is not, however, simply a diluted form of either mainstream (MS) or sidestream (SS) tobacco smoke (Eatough-1989, USSG-1986, NRC-1986-1, NRC-1986-2). Conclusions based on this flawed assumption are bound to be erroneous. 2. "Upward trend in dose-response. ... Differences in life-style and culture may be a factor in the Japanese study reporting a stronger association between ETS and lung cancer than the American study (American Cancer Society)." (page 1-4).

- 5 - The differences between the United States and Japanese cultures may well lead to an explanation of the increased incidence of lung cancer reported in some studies among nonsmoking Japanese wives. For example, the tradition of locating small "job shops" or family-owned mini production lines in an area of a family's home may introduce traditional (and uncontrolled) workplace exposures into a non-traditional workplace (the family residence). Since such exposures are a source of particles and other combustion products, they can cause a serious confounding of the epidemiologic studies and make cross-cultural comparisons inappropriate. None of these factors is discussed in the EPA Draft Report. Taken alone, these cultural differences justify the need for using appropriate markers (other than nicotine and cotinine) to assess exposure to ETS. 3. "Detectable association at environmental exposure levels. Within the population of women who are lifelong nonsmokers, the excess lung cancer risk of those married to a smoker is large enough to be observed. Carcinogenic responses are usually detectable only in high exposure circumstances, such as occupational settings or in highly dosed experimental animals." (page 1-4) Since humans are uniquely affected by their individual lifelong exposure to various environmental pollutants, some attempt to describe the past exposure history to "ETS-like materials" (e.g., respirable suspended particles, combustion

- 6 - by-products, etc.) must be an integral part of any exposure assessment of ETS. Epidemiologists have largely failed in this endeavor. Indeed, the studies appear to assume, entirely unrealistically, that the non-smoking women subjects: 1. were never exposed to any hazardous chemicals during their entire lifetimes; 2. never worked outside the home in a traditional workplace; 3. never worked on the war-time assembly lines in the United States or their country of birth; 4. never lived in homes with high radon levels or friable asbestos; and 5. never worked in locations with high radon levels or friable asbestos. In addition to these misguided assertions, page 2-1 of the Introduction to the EPA Draft Report states that: "Passive and active smokers are exposed to many of the same carcinogens, however, and active smoking has been firmly established as causually related to lung cancer. It is biologically plausible that passive smoking is also casually related to lung cancer." This statement implies that reliable exposure assessments are available for both the active smoker and the ETS-exposed non-smoker. As described above, however, using nicotine and cotinine as surrogates for exposure to the complex material known as ETS is not scientifically justified. Further, the

- 7 - statement ignores the fact that ETS is not physically or chemically the same as sidestream or mainstream smoke, and the mechanism of exposure to mainstream smoke likewise is not at all similar to exposure to ETS. In making this statement, the authors have elected to ignore a large body of scientific literature on the chemistry and exposure assessment of ETS (e.g., Eatough, Goodfellow, Leaderer). Furthermore, this statement appears to be based on the EPA's limited description of ETS that is found on page 2.1 of the Introduction: "Environmental tobacco smoke (ETS) to which a passive smoker is exposed principally consists of SS, usually in greatly diluted concentrations depending on the proximity to the source and related environmental conditions., e.g., ventilation. Aging also affects the composition of chemicals in ETS and their relative distributions between the vapor and particulate phases." During the past seven years, several descriptions for ETS have appeared in the literature. While all of these descriptions display various shortcomings, none is as simplistic and obviously inadequate as that presented in the EPA Draft Report. * * * The remainder of this review focuses on: ° the composition of ETS; ° the physical and chemical comparisons of SS, MS and ETS;

8 ° providing an unambiguous description of ETS; and ° a review of basic exposure assessment. This review will show that a comparison MS or SS and ETS is not scientifically justified. An unambiguous description of ETS is essential if a scientifically credible peer review of the EPA Draft Report is to be performed. EXISTING DESCRIPTIONS OF ETS A number of conferences and publications have discussed ETS in the past seven years. Typically, one of the first issues addressed involves the proper characterization of ETS. The proceedings of a symposium on ETS held at McGill University in Montreal in November 1989 include a description of the "Chemical Characteristics of Environmental Tobacco Smoke," presented by D. J. Eatough et al. This article was prepared from a physical-chemical perspective and includes a review of the world's literature of over 130 references on the topic. This is the latest -- and, in my judgment, the best and most complete -- treatment of the subject. A summary of its major points is provided below. Eatough et al. begin their review with a chemical- by-chemical comparison of SS and MS. Data on the composition of MS and SS originate from laboratory studies. In these studies, various tobacco products are burned and measurements are taken in order to compare the yields of the specific

9 components in the MS or SS. The tobacco products are smoked by machines and the laboratory studies are intended to simulate, though not to reproduce, human smoking habits. A laboratory test to compare the yields of specific compounds is not an appropriate test to be used to characterize ETS. The test chamber and analytical system are designed to maximize the collection of the SS. SS smoke is generated in a special chamber to establish reproducible analytical chemical data. These chamber studies are performed with minimum dilution and at temperatures several hundred degrees Celsius above room temperature where ETS exists. This ensures that the cigarette burns evenly during puff intervals when a diluent air stream of 25 ml per second is drawn through the chamber. At a volume of 25 ml per minute (0.05) cubic feet per minute) there is a minimal amount of dilution of the SS. This is necessary if the concentration of gases and vapors is to be above the minimum detection limits of the various analytical techniques, but it does not represent the actual indoor environment. Indoors, hot SS cools from about 300°C and mixes with room air, the furnishings, and the fabric in the space at room temperature. Other factors such as relative humidity, particle concentration, and temperature may also affect the characteristics of ETS. Machine smoking patterns cause a greater amount of tobacco to be consumed during MS generation. Consequently, the quantity of tobacco burned between puffs is diminished,

and lower amounts of combustion products are released as SS. This produces changes in total particle number, total particle mass, and total gas phase hydrocarbons with ETS aging. Eatough et al. describe several chamber studies to illustrate the complex chemical reactions that occur in a non-reactive Teflon chamber. The issue of the aging of ETS in varying indoor environments with different surface types, textures and chemistry is still not fully resolved. As stated in the Eatough et al. paper: ". . . ETS is a complex mixture of gases and particulate phase compounds. During aging of ETS in an indoor environment, changes will occur in the chemical composition. Just as seen in chamber studies, these changes will include coagulation of particles which will alter the particle size distribution, changes in the gas/particle distribution of semivolatile compounds, and chemical changes due to reactions. In addition, the chemical composition of ETS may be altered during aging in an indoor environment because of differences in the removal rate of various constituents as the ETS is aged." (page 21). Eatough et al. go on to review the complex chemistry involved in the formation of ETS and offer a comparison of constituents in MS, SS and ETS. The paper also expands on the related discussion in the 1986 Surgeon General's report (USSG-1986 page 135): "However, comparisons of MS and ETS should include the consideration of the differences between the two aerosols with regard to their chemical composition, including PH levels, and their physiochemical nature (particle size, air