Zhou Ying, Li Chaoyang, Huijbregts Mark A J, Mumtaz M Moiz
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.
Department of Environmental Science, Institute for Water and Wetland Research, Radboud University Nijmegen, NL-65OO GL, Nijmegen, The Netherlands.
PLoS One. 2015 Oct 7;10(10):e0140013. doi: 10.1371/journal.pone.0140013. eCollection 2015.
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.
从单一污染物治理方法转向多污染物治理方法，能够更有效地实现空气污染的公共卫生防护。要制定此类多污染物治理方法，确定哪些空气污染物出现频率最高至关重要。本研究旨在确定美国各地经常发现的致癌空气毒物或有害空气污染物（HAPs）组合，并分析因接触这些HAPs而患癌对健康产生的影响。为了确定最常见的致癌空气毒物组合，我们首先根据美国环保署（EPA）2005年的全国空气毒物评估（NATA），确定在美国超过5%的人口普查区中癌症风险大于百万分之一的HAPs。然后，我们计算了它们的两组分（二元）和三组分（三元）组合的出现频率。为了量化与癌症相关的健康影响，我们重点关注了全国平均癌症风险大于百万分之一的10种最常发现的HAPs。通过将NATA 2005报告的终生癌症风险转换为健康生命损失年数或伤残调整生命年（DALYs），计算了它们与癌症相关的健康影响。我们发现，癌症风险大于百万分之一的最常发现的空气毒物是甲醛、四氯化碳、乙醛和苯。最常出现的二元对和三元混合物是这四种空气毒物的各种组合。对城市和农村HAPs的分析并未发现这些化学物质顶级组合之间存在显著差异。在美国，吸入排名前十的致癌空气毒物所导致的与癌症相关的累积年度健康影响约为1600个DALYs，即每10万人0.6个DALYs。甲醛和苯共同造成了近60%的与癌症相关的总健康影响。我们的研究表明，尽管有许多致癌空气毒物，但根据空气毒物混合物的出现频率和与癌症相关的公共卫生影响，在美国全国范围内，只有少数几种对公众健康有显著影响。未来需要对它们的联合毒性和累积健康影响进行研究。
