title: Carcinogenic Air Toxics Exposure and Their Cancer-Related Health Impacts in the United States.
abstract: Public health protection from air pollution can be achieved more effectively by shifting from a single-pollutant approach to a multi-pollutant approach. To develop such multi-pollutant approaches, identifying which air pollutants are present most frequently is essential. This study aims to determine the frequently found carcinogenic air toxics or hazardous air pollutants (HAPs) combinations across the United States as well as to analyze the health impacts of developing cancer due to exposure to these HAPs. To identify the most commonly found carcinogenic air toxics combinations, we first identified HAPs with cancer risk greater than one in a million in more than 5% of the census tracts across the United States, based on the National-Scale Air Toxics Assessment (NATA) by the U.S. EPA for year 2005. We then calculated the frequencies of their two-component (binary), and three-component (ternary) combinations. To quantify the cancer-related health impacts, we focused on the 10 most frequently found HAPs with national average cancer risk greater than one in a million. Their cancer-related health impacts were calculated by converting lifetime cancer risk reported in NATA 2005 to years of healthy life lost or Disability-Adjusted Life Years (DALYs). We found that the most frequently found air toxics with cancer risk greater than one in a million are formaldehyde, carbon tetrachloride, acetaldehyde, and benzene. The most frequently occurring binary pairs and ternary mixtures are the various combinations of these four air toxics. Analysis of urban and rural HAPs did not reveal significant differences in the top combinations of these chemicals. The cumulative annual cancer-related health impacts of inhaling the top 10 carcinogenic air toxics included was about 1,600 DALYs in the United States or 0.6 DALYs per 100,000 people. Formaldehyde and benzene together contribute nearly 60 percent of the total cancer-related health impacts. Our study shows that although there are many carcinogenic air toxics, only a few of them affect public health significantly at the national level in the United States, based on the frequency of occurrence of air toxics mixtures and cancer-related public health impacts. Future research is needed on their joint toxicity and cumulative health impacts.
authors.affiliation: Environmental Health Tracking Branch, Division of Environmental Hazards and Health Effects, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Environmental Health Tracking Branch, Division of Environmental Hazards and Health Effects, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Chaoyang
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Environmental Science, Institute for Water and Wetland Research, Radboud University Nijmegen, NL-65OO GL, Nijmegen, The Netherlands.
authors.forename: Mark A J
authors.initials: MA
authors.lastname: Huijbregts
authors.affiliation: Computational Toxicology Laboratory, Division of Toxicology and Human Health Sciences, Agency for Toxic Substances and Disease Registry, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: M Moiz
authors.initials: MM
authors.lastname: Mumtaz
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D001554:Benzene / Q000633:toxicity; D002251:Carbon Tetrachloride / Q000633:toxicity; D002273:Carcinogens / Q000633:toxicity*; D005557:Formaldehyde / Q000633:toxicity; D015386:Hazardous Substances / Q000633:toxicity; D006801:Humans; D009369:Neoplasms / Q000209:etiology*; D011634:Public Health; D018570:Risk Assessment; D014481:United States; D014484:United States Environmental Protection Agency
chemical_list: D000393:Air Pollutants; D002273:Carcinogens; D015386:Hazardous Substances; D005557:Formaldehyde; D002251:Carbon Tetrachloride; D001554:Benzene