AIR POLLUTION AND CANCER - IARC

PREFACEEmissions from motor vehicles, industrialprocesses, power generation, the householdcombustion of solid fuel, and other sources pollutethe ambient air across the globe. The precisechemical and physical features of ambient airpollution, which comprise a myriad of individualchemical constituents, vary around the worlddue to differences in the sources of pollution,climate, and meteorology, but the mixtures ofambient air pollution invariably contain specificchemicals known to be carcinogenic to humans.Recent estimates suggest that the diseaseburden due to air pollution is substantial.Exposure to ambient fine particles (PM2.5) wasrecently estimated to have contributed 3.2 millionpremature deaths worldwide in 2010, due largelyto cardiovascular disease, and 223 000 deathsfrom lung cancer. More than half of the lungcancer deaths attributable to ambient PM2.5 wereestimated to have been in China and other EastAsian countries (Lim et al., 2012).In February 2003, the IARC MonographsAdvisory Group on Priorities for FutureEvaluations recommended that IARC developa series of Monographs on air pollution. Thetopic is obviously complex, given the varietyof environments where exposures to airbornecarcinogens take place, the diversity of thesources, and the numerous components of theair pollution mixture that may contribute toits carcinogenicity. Recognizing this, the 2003Advisory Group recommended that there be afocused Advisory Group to plan a series of IARCMonographs on air pollution.In December 2004, this special AdvisoryGroup meeting was convened in Lyon.Participants provided a state-of-the-art overviewon topics related to exposure characterization,atmospheric and engineering sciences, epidemiological studies on cancer, results of pertinentcancer bioassays, and data elucidating potentialmechanisms of carcinogenicity of compoundsrelated to air pollution. These presentations werefollowed by discussions in subgroups established according to the structure of the IARCMonographs (exposure, cancer in humans,cancer in experimental animals, and other relevant data) and plenary sessions to identify allmajor issues that were critical for the development of the series of Monographs. Specifically,the participants were tasked with the following: Develop a list of agents and exposures to beevaluated in a series of IARC Monographs on airpollution and cancer. Identify the key issues to consider in theevaluations and critical research gaps. Make recommendations for bundlingrelated agents into the same meeting. Make recommendations on the sequencingand scheduling of the meetings.According to these recommendations, subsequent Monographs meetings were held over thenext few years:5

IARC SCIENTIFIC PUBLICATION – 161 Volume 92 (October 2005): Some non-heterocyclic polycyclic aromatic hydrocarbons andsome related exposures (IARC, 2010a). Volume 93 (February 2006): Carbon black,titanium dioxide, and talc (IARC, 2010b). Volume 95 (October 2006): Householduse of solid fuels and high-temperature frying(IARC, 2010c). Volume 103 (October 2011): Bitumensand bitumen emissions, and some N- andS-heterocyclic polycyclic aromatic hydrocarbons(IARC, 2013a). Volume 105 (June 2012): Diesel and gasolineengine exhausts and some nitroarenes (IARC,2013b).As preparation began for the sixth meetingin this series of Monographs on air pollution(Volume 109: Ambient air pollution), the needto provide an overview and detailed backgroundinformation on different aspects of air pollutionand cancer took on renewed importance. To thatend, it was decided to update earlier draft manuscripts that had been prepared based on presentations at the initial Advisory Group meetingin 2004. While serving as a Visiting Scientist inthe IARC Monographs section, Aaron Cohenworked with Jonathan Samet, chair of theAdvisory Group meeting in 2004, and IARC tomanage this update and ensure publication beforethe IARC Monographs meeting on ambient airpollution in October 2013. The book that resultednow includes the following chapters: A working group report (written by JonathanSamet on behalf of the Advisory Group); so asto capture the original recommendations ofthe Advisory Group, this chapter has not beenupdated. Eleven of the original manuscripts have beencompletely revised and updated by the originalauthors or by experts not present at the initialAdvisory Group meeting.6 Two of the original manuscripts (by Vineiset al. and Katsouyanni et al.) have been updatedwith an addendum.We acknowledge the support and encouragement of all the contributing authors duringthe development phase of this book. We extendour special thanks to all the authors for theirendurance and their updates of the manuscripts. The editors would also like to acknowledge the critical support of Jennifer Brandt, thetechnical editor of this book, and the excellentsupport of IARC’s publications team: SolèneQuennehen, Sylvia Lesage, Karen Müller, andNicolas Gaudin. Financial support for theinitial Advisory Group meeting was providedby World Health Organization/United StatesEnvironmental Protection Agency CooperativeAgreement No. CR 831057. This contribution isgratefully acknowledged.ReferencesIARC (2010b). Carbon black, titanium dioxide, and talc.IARC Monogr Eval Carcinog Risks Hum, 93: 1–413.PMID:21449489IARC (2010c). Household use of solid fuels and high-temperature frying. IARC Monogr Eval Carcinog RisksHum, 95: 1–430. PMID:20701241IARC (2010a). Some non-heterocyclic polycyclicaromatic hydrocarbons and some related exposures.IARC Monogr Eval Carcinog Risks Hum, 92: 1–853.PMID:21141735IARC (2013a). Bitumens and bitumen emissions, andsome N- and S-heterocyclic polycyclic aromatic hydrocarbons. IARC Monogr Eval Carcinog Risks Hum, 103:1–342.IARC (2013b). Diesel and gasoline engine exhausts andsome nitroarenes. IARC Monogr Eval Carcinog RisksHum, 105 (in press).Lim SS, Vos T, Flaxman AD et al. (2012). A comparativerisk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21regions, 1990–2010: a systematic analysis for the GlobalBurden of Disease Study 2010. Lancet, 380: 2224–2260.doi:10.1016/S0140-6736(12)61766-8 PMID:23245609

CHAPTER 1. INTRODUCTIONJonathan M. SametPeople take thousands of breaths daily,leading to a total intake of about 10 000 litresof air per day. Consequently, the lung receivessignificant doses of many air contaminants,even those present at seemingly low and trivialconcentrations. Around the world, people spendtime in many different kinds of places, oftenreferred to as microenvironments: their homes,workplaces, public places, other indoor environments, transportation, and outdoors. In allof these locations there are sources that emitairborne carcinogens that can be readily detectedin indoor and outdoor air. Globally, combustionof fuels for heating, cooking, power generation,and industrial processes is a ubiquitous source.Combustion sources range from the burningof dung in open fires to highly sophisticated,massive combustion sources, such as coal-firedpower plants, that may be equipped with controltechnology for particles and gases. Combustionengines, particularly for motor vehicles, areanother worldwide source. Indoors there arecarcinogens from tobacco smoking, buildingmaterials, and furnishings, as well as the naturally occurring carcinogen radon.The extent of exposures to indoor andoutdoor air pollution is well recognized. Therehas long been concern that airborne carcinogens contribute to the global burden of cancer,especially of the lung, which receives the mostsubstantial inhaled doses. However, the topic ofair pollution and cancer has not been reviewedsystematically, particularly in its global dimensions. There is a rationale for undertaking such acomprehensive review: the more than 1.3 millionnew cases of lung cancer per year worldwide.Even a small contribution from air pollutionto this number would strengthen the justification for implementing tighter control measures.In fact, several specific carcinogens or sourcesof carcinogens in indoor and outdoor air havealready been the focus of substantial research andtargeted control initiatives (e.g. diesel enginesand exhaust, and radon and second-hand smokeindoors). In developing countries, high-levelexposures to smoke from biomass fuels occur forbillions of children and adults.Estimates have been made of the burden ofcancer attributable to environmental factors andof the contribution of air pollution to lung cancerspecifically. Estimates have also been made forspecific carcinogens, including radon and lungcancer. These estimates have been in the range of3–5% for the fraction of lung cancer cases attributable to ambient air pollution. The 2004 estimates of the World Health Organization’s GlobalBurden of Disease programme covered bothoutdoor and indoor air pollution. For ambient airpollution, the estimated number of lung cancerdeaths worldwide was 62 000 per year (Cohenet al., 2004). Indoor air pollution from solid fuelcombustion was estimated to cause 16 000 lung7

IARC SCIENTIFIC PUBLICATION – 161Table 1.1 Agents of high priority for evaluation or re-evaluationAgent (overall evaluation of carcinogenicity tohumans)aPriorityRationale for evaluation or re-evaluationCarbon black (Group 2B)HighTitanium dioxide (Group 3)HighBitumen (USA: asphalt) (Group 2B/3)HighDiesel engine exhaust (Group 2A)Gasoline engine exhaust (Group 2B)HighLowAir pollution, outdoor and indoorSulfur dioxide (Group 3)HighHighLowHighNew epidemiological studiesNew animal carcinogenicity dataMechanistic discussion (ultrafine particles)New epidemiological studiesM

IARC Library Cataloguing in Publication Data Air pollution and cancer / editors, K. Straif, A. Cohen, J. Samet (IARC Scientific Publications; 161) 1. Air Pollutants 2. Environmental Pollutants 3. Air Pollution, Indoor 4. Carcinogens, Envir