Wildfire smoke now bigger prenatal threat than human sources of air pollution
Wildfire smoke now bigger prenatal threat than human sources of air pollution
野火烟雾现已成为比人为空气污染源更大的产前健康威胁
In 1965, a presidential advisory panel issued a report warning that pervasive chemical and carbon pollution was harming environmental health and changing the climate. Five years later, President Richard Nixon signed the Clean Air Act. Since that 1970 law and its amendments were passed, combined emissions of a half-dozen harmful air pollutants from vehicles and industrial sources have decreased by nearly 80 percent.
1965年，一个总统咨询小组发布报告警告称，普遍存在的化学和碳污染正在损害环境健康并改变气候。五年后，理查德·尼克松总统签署了《清洁空气法案》。自1970年该法案及其修正案通过以来，来自车辆和工业源的六种有害空气污染物的总排放量减少了近80%。
But mounting evidence shows that pollution from wildfire smoke is eclipsing those air-quality gains. The unchecked burning of fossil fuels is creating warmer, drier conditions that make wildfires more intense and destructive, and blanket communities in toxic smoke that is more harmful than pollution from other sources. Now, a new study shows that smoke from wildfires is also reversing the health benefits of reducing air pollution for society’s most vulnerable population: babies in the womb.
但越来越多的证据表明，野火烟雾造成的污染正在抵消这些空气质量改善的成果。化石燃料的无节制燃烧正在创造更温暖、更干燥的环境，使野火变得更加猛烈和具有破坏性，并使社区笼罩在比其他污染源更有害的有毒烟雾中。现在，一项新的研究表明，野火烟雾也正在抵消减少空气污染为社会最脆弱群体——胎儿——带来的健康益处。
Increasing wildfire activity is “systematically offsetting prenatal air quality gains” from reducing emissions from vehicles, refineries, factories and other human sources, researchers from the University of Maryland, College Park, report in the study, published Thursday in Frontiers in Environmental Health. Low-income, rural and Indigenous populations bore the disproportionate burden of wildfire’s contribution to poor air quality, the authors found.
马里兰大学帕克分校的研究人员周四在《环境健康前沿》杂志上发表的研究报告称，日益频繁的野火活动正在“系统性地抵消”因减少车辆、炼油厂、工厂和其他人为源排放而带来的产前空气质量改善。作者发现，低收入群体、农村人口和原住民在野火导致的空气质量恶化中承受了不成比例的负担。
The major contribution of the study is its focus on a “very specific population that is quite at risk for adverse health outcomes,” said senior author Michel Boudreaux, associate professor of health policy and management. “We were looking at infants that were born and what their exposure was like during the prenatal period.”
该研究的主要贡献在于其关注了一个“极易出现不良健康后果的特定群体”，资深作者、卫生政策与管理副教授米歇尔·布德罗（Michel Boudreaux）表示。“我们研究的是新生儿，以及他们在产前阶段的暴露情况。”
Prenatal exposure to wildfire smoke significantly increases the likelihood that babies will be born too early or too small, raising their risk of dying early or developing chronic respiratory conditions and other diseases later in life.
产前接触野火烟雾会显著增加婴儿早产或体重过轻的可能性，从而提高他们早夭或在日后生活中患上慢性呼吸道疾病及其他疾病的风险。
The University of Maryland team studied how wildfire smoke and human sources of air pollution changed across the contiguous United States between 2003 and 2019, looking at air pollution data from the Environmental Protection Agency and live birth records. (The EPA datasets do not include years beyond 2019.) To understand how much wildfire smoke contributed to unhealthy air exposures for unborn babies, the team used computer models to estimate exposures to fine particle pollution, or PM2.5, from both human sources, such as cars and industry, and natural sources, like wildfires.
马里兰大学的研究团队研究了2003年至2019年间美国本土各地的野火烟雾和人为空气污染源的变化情况，并查阅了美国环境保护署（EPA）的空气污染数据和活产记录。（EPA的数据集不包含2019年以后的年份。）为了了解野火烟雾对未出生婴儿的不健康空气暴露贡献了多少，研究团队利用计算机模型估算了来自汽车和工业等人为源，以及野火等自然源的细颗粒物（PM2.5）暴露量。
The team modeled air quality without emissions from fires to calculate how much of that total pollution came from wildfires. The researchers obtained data for nearly 65 million babies born over 16 years and determined how many days they were exposed in the womb to the EPA threshold for unhealthy air. Average daily prenatal exposure to air pollution from human sources dropped by 37 percent during that time, the analysis found, but contributions from wildfires doubled, offsetting those gains.
研究团队模拟了没有火灾排放情况下的空气质量，以计算总污染中有多少来自野火。研究人员获取了16年间近6500万名新生儿的数据，并确定了他们在胎儿期内有多少天暴露在EPA定义的“不健康空气”阈值之下。分析发现，在此期间，产前每日接触人为空气污染的平均水平下降了37%，但来自野火的贡献却翻了一番，抵消了这些改善成果。
Although the study does not integrate data on preterm birth, birthweight or other outcomes, it is a very good exposure-characterization study, said Ilona Jaspers, an inhalation toxicologist and professor of pediatrics at the University of North Carolina, Chapel Hill, who was not involved in the study. “What this study does do well is confirm and expand the well-established finding that ambient PM2.5 in the United States is increasingly wildfire-dominated, offsetting Clean Air Act gains, but applies a birth-weighted lens to it,” she said.
北卡罗来纳大学教堂山分校的吸入毒理学家兼儿科教授伊洛娜·贾斯珀斯（Ilona Jaspers）表示，虽然该研究没有整合早产、出生体重或其他结果的数据，但它是一项非常出色的暴露特征研究。她并未参与此项研究。“这项研究做得很好的一点是，它证实并扩展了一个既定结论，即美国的环境PM2.5正日益由野火主导，抵消了《清洁空气法案》带来的成果，并且它采用了以出生为权重的视角来审视这一问题，”她说。
Wildfire smoke exposures are likely to have vast public health consequences, Jaspers said. In previous studies, Jaspers and her colleagues used prescription insurance claim data to show that exposure during specific perinatal periods can lead to childhood respiratory diseases.
贾斯珀斯表示，接触野火烟雾可能会产生巨大的公共卫生后果。在之前的研究中，贾斯珀斯和她的同事利用处方保险索赔数据证明，在特定的围产期接触烟雾可能导致儿童呼吸道疾病。
The research doesn’t look at how much time the mother was spending outside, if she wore an N95 mask or if she had an air-filtration system in her home, which Boudreaux acknowledges as a limitation of the study. But data sources like Purple Air that track wildfire smoke are detecting a large amount of pollution in the form of a PM2.5 inside people’s homes, he said.
这项研究没有考察母亲在户外停留的时间、是否佩戴N95口罩或家中是否有空气过滤系统，布德罗承认这是该研究的局限性。但他表示，像Purple Air这样追踪野火烟雾的数据源显示，人们家中检测到了大量的PM2.5污染。
The new study highlighted regions and populations that were disproportionately affected by wildfire smoke. In the West and Northwest, wildfires’ contributions to air pollution more than doubled over the study period. And the communities where wildfires are responsible for the largest reversals in air quality—low-income, rural and American Indian and Alaska Native populations—often have the least access to neonatal care.
这项新研究强调了受野火烟雾影响不成比例的地区和人群。在西部和西北部，野火对空气污染的贡献在研究期间增加了一倍以上。而那些因野火导致空气质量恶化最严重的社区——低收入群体、农村人口以及美洲印第安人和阿拉斯加原住民——往往最缺乏新生儿护理资源。
Since exposure to wildfire smoke early in life can cause life-long health problems, reducing exposure in the prenatal period will yield long-term benefits, Boudreaux said. The last six years have seen several catastrophic fires in the West and Canada, Boudreaux said. If the team were to extend the study through 2026, he said, they’d likely see wildfires make an even higher contribution to unhealthy prenatal exposures.
布德罗表示，由于生命早期接触野火烟雾会导致终身的健康问题，减少产前阶段的接触将带来长期的益处。布德罗指出，过去六年里，西部和加拿大发生了多起灾难性火灾。他说，如果团队将研究延长至2026年，他们很可能会看到野火对不健康产前暴露的贡献更高。
But that’s just speculation, he cautioned. What is clear, he said, is that wildfire smoke now accounts for an increasing share of “acute, massive air pollution days” that endanger babies’ health. “What that tells me is that the next frontier is how do we help people manage exposure to wildfire smoke, which is a different kind of exposure than ambient pollution from other sources.”
但他提醒说，这只是推测。他说，明确的是，野火烟雾现在在危及婴儿健康的“急性、大规模空气污染日”中所占的比例越来越大。“这告诉我的下一阶段重点是，我们如何帮助人们管理对野火烟雾的暴露，这与来自其他来源的环境污染暴露是不同的。”
That means providing communities with resources like clean-air shelters, air filters and better access to healthcare when they are exposed, he said. Ultimately, he said, “we should be asking, are there things we can do to reduce the risk of climate change in general?”
这意味着要为社区提供诸如清洁空气避难所、空气过滤器等资源，并在他们暴露时提供更好的医疗服务，他说。最后，他表示：“我们应该问的是，我们能做些什么来降低气候变化的总体风险吗？”