로렌스-버클리 연구소의 과학자 Lara Gundel와 Michael Apte 등은  흡연자의 옷이나 머리카락 등에 묻은 유해성분을 통해 폐암이나 천식이 발생할 수 있다는 3차 흡연(third-hand smoke)의 위험성을 규명한 연구결과를 2010년 초 발표한 바 있습니다. 3차 흡연을 통해 유전자 돌연변이가 일어나 DNA의 변형을 일으키기 때문입니다.

흡연자의 가족들은 위암, 폐암 등에 걸릴 위험이 더 높아지는데… 이는 담배연기 속의 유해성분이 베인 옷이나 카펫트, 벽지 등에서 2개월 동안 잔류해 있으면서 실내 공기 중에 존재하는 아질산(the common indoor air pollutant nitrous acid)과 섞여서 니트로스아민을 형성하기 때문으로 밝혀졌습니다.(니트로스아민은 담배에 있는 유해성분은 아닙니다. 흡연 후 2차적 또는 3차적으로 실내 공기에서 형성되는 발암물질입니다)

Study reveals dangers of nicotine in third-hand smoke

Lawrence Berkeley National Laboratory scientists Lara Gundel and Michael Apte contributed to the study, which was led by Ruiling Liu and Katharine Hammond from UC Berkeley’s School of Public Health. The results were published in the journal Tobacco Control in a paper titled, “Assessment of risk for asthma initiation and cancer and heart disease deaths among patrons and servers due to secondhand smoke exposure in restaurants and bars.”

Taking exposure data from 65 restaurants and bars in Minnesota over an eight-month period in 2007, the researchers found that the lifetime excess risk of lung cancer death was 18 in a million for patrons visiting only nonsmoking sections and 80 in a million for patrons in the smoking section. For servers, the lifetime excess risk was 802 in a million for lung cancer death.

Extrapolating to the entire country, the researchers estimate that the lifetime excess risk for the general nonsmoking population due to exposure to secondhand smoke in restaurants and bars would result in 214 additional lung cancer deaths and 3,001 additional heart disease deaths per year.

“One in a million is significant,” said Gundel. “You can’t control people smoking, but to support tobacco-free policies we need to know how to protect people.”

Although smoking bans have been enacted in many parts of the country, one quarter of the U.S. population remains unprotected by smoke-free policies in restaurants and 35 percent in bars, according to the study. Globally 95 percent of the population is unprotected by smoke-free policies in restaurants and bars. Moreover tobacco companies continue to fight smoking bans, and increasing numbers of cities are repealing or weakening them.

While previous studies have examined health risks for people working in restaurants and bars, none had quantified risks to patrons. In the U.S. 66 percent of adults eat out at least weekly, and for nonsmokers restaurants and bars may be their predominant source of secondhand smoke exposure. The researchers assumed weekly visits to restaurants for 60 years.

This was also the first study to look at servers’ risk of asthma initiation due to secondhand smoke exposure. They estimated the risks to correspond to 1,420 new asthma cases per year among nonsmoking servers in the United States.

“There are huge economic impacts related to smoking,” Gundel said. “It’s worth it to society to try to minimize the damage from smoking.”

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Secondhand Smoke in Bars and Restaurants Means Higher Risk of Asthma and Cancer

Julie Chao (510) 486-6491  JHChao@lbl.gov

Nicotine in third-hand smoke, the residue from tobacco smoke that clings to virtually all surfaces long after a cigarette has been extinguished, reacts with the common indoor air pollutant nitrous acid to produce dangerous carcinogens. This new potential health hazard was revealed in a multi-institutional study led by researchers with the Lawrence Berkeley National Laboratory (Berkeley Lab).

In tests at Berkeley Lab of cellulose surfaces contaminated with nicotine residues from third-hand smoke, levels of newly formed TSNAs rose 10 times following a three hour exposure to nitrous acid. TSNAs are potent carcinogens. (Photo by Roy Kaltschmidt, Berkeley Lab Public Affairs)

“The burning of tobacco releases nicotine in the form of a vapor that adsorbs strongly onto indoor surfaces, such as walls, floors, carpeting, drapes and furniture. Nicotine can persist on those materials for days, weeks and even months. Our study shows that when this residual nicotine reacts with ambient nitrous acid it forms carcinogenic tobacco-specific nitrosamines or TSNAs,” says Hugo Destaillats, a chemist with the Indoor Environment Department ofBerkeley Lab’s Environmental Energy Technologies Division. “TSNAs are among the most broadly acting and potent carcinogens present in unburned tobacco and tobacco smoke.”

Destaillats is the corresponding author of a paper published in the Proceedings of the National Academy of Sciences (PNAS) titled “Formation of carcinogens indoors by surface-mediated reactions of nicotine with nitrous acid, leading to potential third-hand smoke hazards.”

Co-authoring the PNAS paper with Destaillats were Mohamad Sleiman, Lara Gundel and Brett Singer, all with Berkeley Lab’s Indoor Environment Department, plus James Pankow with Portland State University, and Peyton Jacob with the University of California, San Francisco.

The authors report that in laboratory tests using cellulose as a model indoor material exposed to smoke, levels of newly formed TSNAs detected on cellulose surfaces were 10 times higher than those originally present in the sample following exposure for three hours to a “high but reasonable” concentration of nitrous acid (60 parts per billion by volume). Unvented gas appliances are the main source of nitrous acid indoors. Since most vehicle engines emit some nitrous acid that can infiltrate the passenger compartments, tests were also conducted on surfaces inside the truck of a heavy smoker, including the surface of a stainless steel glove compartment. These measurements also showed substantial levels of TSNAs. In both cases, one of the major products found was a TSNA that is absent in freshly emitted tobacco smoke – the nitrosamine known as NNA. The potent carcinogens NNN and NNK were also formed in this reaction.

“Time-course measurements revealed fast TSNA formation, up to 0.4 percent conversion of nicotine within the first hour,” says lead author Sleiman. “Given the rapid sorption and persistence of high levels of nicotine on indoor surfaces, including clothing and human skin, our findings indicate that third-hand smoke represents an unappreciated health hazard through dermal exposure, dust inhalation and ingestion.”

Since the most likely human exposure to these TSNAs is through either inhalation of dust or the contact of skin with carpet or clothes, third-hand smoke would seem to pose the greatest hazard to infants and toddlers. The study’s findings indicate that opening a window or deploying a fan to ventilate the room while a cigarette burns does not eliminate the hazard of third-hand smoke. Smoking outdoors is not much of an improvement, as co-author Gundel explains.

Berkeley Lab chemists Lara Gundel and Hugo Destaillats led a research team that revealed the potential health hazards posed by residual nicotine in third-hand smoke when it reacts with ambient nitrous acid. (Photo by Roy Kaltschmidt, Berkeley Lab Public Affairs)

“Smoking outside is better than smoking indoors but nicotine residues will stick to a smoker’s skin and clothing,” she says. “Those residues follow a smoker back inside and get spread everywhere. The biggest risk is to young children. Dermal uptake of the nicotine through a child’s skin is likely to occur when the smoker returns and if nitrous acid is in the air, which it usually is, then TSNAs will be formed.”

The dangers of mainstream and secondhand tobacco smoke have been well documented as a cause of cancer, cardiovascular disease and stroke, pulmonary disease and birth defects. Only recently, however, has the general public been made aware of the threats posed by third-hand smoke. The term was coined in a study that appeared in the January 2009 edition of the journal “Pediatrics,” in which it was reported that only 65 percent of non-smokers and 43 percent of smokers surveyed agreed with the statement that “Breathing air in a room today where people smoked yesterday can harm the health of infants and children.”

Anyone who has entered a confined space – a room, an elevator, a vehicle, etc. – where someone recently smoked, knows that the scent lingers for an extended period of time. Scientists have been aware for several years that tobacco smoke is adsorbed on surfaces where semi-volatile and non-volatile chemical constituents can undergo reactions, but reactions of residual smoke constituents with atmospheric molecules such as nitrous acid have been overlooked as a source of harmful pollutants. This is the first study to quantify the reactions of third-hand smoke with nitrous acid, according to the authors.

Mohamad Sleiman was the lead author of a paper titled “Formation of carcinogens indoors by surface-mediated reactions of nicotine with nitrous acid, leading to potential third-hand smoke hazards.” (Photo by Roy Kaltschmidt,Berkeley Lab Public Affairs)

“Whereas the sidestream smoke of one cigarette contains at least 100 nanograms equivalent total TSNAs, our results indicate that several hundred nanograms per square meter of nitrosamines may be formed on indoor surfaces in the presence of nitrous acid,” says lead-author Sleiman.

Co-author James Pankow points out that the results of this study should raise concerns about the purported safety of electronic cigarettes. Also known as “e-cigarettes,” electronic cigarettes claim to provide the “smoking experience,” but without the risks of cancer. A battery-powered vaporizer inside the tube of a plastic cigarette turns a solution of nicotine into a smoky mist that can be inhaled and exhaled like tobacco smoke. Since no flame is required to ignite the e-cigarette and there is no tobacco or combustion, e-cigarettes are not restricted by anti-smoking laws.

“Nicotine, the addictive substance in tobacco smoke, has until now been considered to be non-toxic in the strictest sense of the term,” says Kamlesh Asotra of the University of California’s Tobacco-Related Disease Research Program, which funded this study. “What we see in this study is that the reactions of residual nicotine with nitrous acid at surface interfaces are a potential cancer hazard, and these results may be just the tip of the iceberg.”

The Berkeley Lab researchers are now investigating the long-term stability in an indoor environment of the TSNAs produced as a result of third-hand smoke interactions with nitrous acid. The authors are also looking into the development of biomarkers to track exposures to these TSNAs. In addition, they are conducting studies to gain a better understanding of the chemistry behind the formation of these TSNAs and to find out more about other chemicals that are being produced when third-hand smoke reacts with nitrous acid.

“We know that these residual levels of nicotine may build up over time after several smoking cycles, and we know that through the process of aging, third-hand smoke can become more toxic over time,” says Destaillats. “Our work highlights the importance of third-hand smoke reactions at indoor interfaces, particularly the production of nitrosamines with potential health impacts.”

In the PNAS paper, Destaillats and his co-authors suggest various ways to limit the impact of the third hand smoke health hazard, starting with the implementation of 100 percent smoke-free environments in public places and self-restrictions in residences and automobiles. In buildings where substantial smoking has occurred, replacing nicotine-laden furnishings, carpets and wallboard might significantly reduce exposures.

Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California.  It conducts unclassified scientific research for DOE’s Office of Science and is managed by the University of California. Visit our Website at www.lbl.gov/

Additional Information

For more information about Berkeley Lab’s Indoor Environment Department and its researchers visit the Website at http://eetd.lbl.gov/r-indoor.html

For more information on the research of James Pankow visit the Website athttp://www.pdx.edu/chem/profile/dr-james-f-pankow

For more information on the research of Peyton Jacob visit the Website athttp://cancer.ucsf.edu/people/jacob_peyton.php

For more information on the University of California’s Tobacco-Related Disease Research Program (TRDRP) visit the Website at http://www.trdrp.org

For a list of health experts who may be able to provide comments and quotes, contact Kamlesh Asotra at kamlesh.asotra@ucop.edu or 510-287-3366.

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[참고]

로렌스-버클리 연구소의 성장

http://www.postech.ac.kr/press/hs/C30/C30S001.html

 

 

지금의 로렌스 버클리 연구소(야경) 초기 방사연구소 건물 앞의 로렌스 초기 방사 연구소