2026-02-05T06:27:00-0500 / CBS新闻
一项新研究表明，长期暴露于野火烟雾污染与美国每年数万例死亡相关联。
该研究论文于周三发表在《科学进展》(Science Advances)杂志上，发现2006年至2020年间，美国本土48州长期暴露于野火烟雾中的微小颗粒物，平均每年导致24,100人死亡。
“我们的结论是：野火烟雾非常危险，它对人类健康的威胁日益增加，”该研究作者、西奈山伊坎医学院环境医学系助理教授魏亚光(Yaguang Wei)表示。
其他研究野火烟雾死亡人数的科学家对这一发现并不感到意外。
“他们得出的估计是合理的，”加州大学洛杉矶分校环境健康科学教授迈克尔·杰瑞特(Michael Jerrett)表示，他并未参与这项研究。”我们需要更多这样的研究。只有通过多种不同设计的研究，我们才能对研究结果建立科学信心。”
“这些是因野火烟雾而失去的真实生命”
该研究论文的研究人员重点关注了与慢性暴露于细颗粒物(PM2.5)相关的死亡——PM2.5是野火烟雾中的主要有害物质。
这些颗粒物可深入肺部并进入血液。短期暴露会引发咳嗽和眼睛发痒，但长期暴露会加重现有健康问题，并导致一系列慢性和致命的健康问题，包括呼吸系统疾病、心血管疾病、神经系统疾病以及过早死亡。
“野火烟雾中的PM2.5已成为美国重要的环境危害，而气候变化导致野火的频率和强度不断增加，”西奈山伊坎医学院博士后研究员、该研究作者张敏(Min Zhang)表示。
杰瑞特指出，除了数十年的森林管理不善，火灾高发地区不断扩大的”城市-荒野交界带”也增加了野火风险，对人类健康造成了切实影响。
“除非火灾真的烧毁了某人或树木倒塌砸中某人，否则死亡证明上不会出现’野火死亡’的字样，”杰瑞特说。”但许多因暴露于烟雾中而死亡的人本就更为脆弱。这些是真实失去的生命，这不是一个随意的抽象统计概念。”
根据去年8月发表的研究，2025年席卷洛杉矶的火灾可能比最初估计的更致命。在这项研究中，研究人员分析了2025年1月5日至2月1日期间洛杉矶县的死亡数据——此时帕利塞兹(Palisades)和伊顿(Eaton)火灾肆虐该市——并估计与往年数据相比，可能有440人死亡可归因于这些火灾。
一名消防员在2025年1月8日于加利福尼亚州帕萨迪纳发生的伊顿火灾中灭火。约书亚·埃德尔森(JOSH EDELSON)/法新社/盖蒂图片社
2024年的一项研究估计，2008年至2018年间，加利福尼亚州有数万人因野火烟雾导致过早死亡。
据哥伦比亚广播公司新闻湾区分部报道，该研究估计2008年至2018年间，索诺玛县因野火烟雾导致的PM2.5暴露死亡人数为2,305人，圣克拉拉县为2,231人，康特拉科斯塔县为2,063人，阿拉米达县为2,057人。
研究人员如何开展这项研究
该研究的作者分析了美国本土48州每年平均暴露于野火烟雾中的PM2.5与各县死亡人数之间的关联。他们使用了3,068个县的联邦死亡率数据，涵盖所有死因以及几种特定死因——循环系统疾病、神经系统疾病、呼吸系统疾病，以及精神和行为障碍、肿瘤和内分泌、营养及代谢疾病。
他们还纳入了与跌倒和交通事故相关的死亡——这些死亡不太可能与野火烟雾相关——以确保其他观察结果无偏差。
“我们发现交通事故和跌倒与PM2.5暴露无关联，而其他疾病的死亡率却有统计学上的显著影响，”魏亚光表示。其中，神经系统疾病死亡人数增加最为显著。
颗粒物暴露与死亡之间的关联强度因季节和人口统计特征而异。在较凉爽的季节关联更强，农村地区和年轻社区的人群似乎更为脆弱。
研究人员还发现，每立方米空气中PM2.5浓度每增加0.1微克，每年约有5,594人死亡。
杰瑞特表示，这项研究的优势在于样本量较大，并且涵盖了美国大多数死因。但他指出，由于野火烟雾的分布非常动态，各县级数据可能存在高估或低估的情况。”烟雾不会同时覆盖整个大县，该县内某些地区的烟雾浓度会严重得多。”
他还指出，该研究未考虑其他重要因素，如个人是否吸烟。
气候政策倒退带来风险，研究作者表示
耶鲁大学公共卫生学院环境科学副教授陈凯(Kai Chen)也研究过这一课题，他表示：”我非常赞赏他们同时研究了烟雾PM2.5和非烟雾PM2.5。”陈凯通过电子邮件表示，多项研究发现，来自野火烟雾的PM2.5对健康的影响比汽车排放等其他来源的污染更大。
该研究作者指出，特朗普政府在气候变化政策上的倒退——尽管全球变暖在很大程度上导致了更具破坏性的野火变得更加频繁——带来了重大风险。他们表示，量化野火PM2.5对人类健康的致命威胁表明，需要有效的、紧迫的缓解策略，并得到美国环境保护局(EPA)的监测和监管支持。
“这凸显了控制野火来源PM2.5的重要性，而目前EPA并未将其列为受监管污染物，通常将其视为自然灾害，”陈凯表示。
Wildfire smoke pollution linked to tens of thousands of deaths in U.S. per year, study finds
2026-02-05T06:27:00-0500 / CBS News
Chronic exposure to pollution from wildfires has been linked to tens of thousands of deaths annually in the United States, according to a new study.
The paper, published Wednesday in the journal Science Advances, found that from 2006 to 2020, long-term exposure to tiny particulates from wildfire smoke contributed to an average of 24,100 deaths a year in the lower 48 states.
“Our message is: Wildfire smoke is very dangerous. It is an increasing threat to human health,” said Yaguang Wei, a study author and assistant professor in the department of environmental medicine at Icahn School of Medicine at Mount Sinai.
Other scientists who have studied the death toll from wildfire smoke were not surprised by the findings.
“The estimates they’re coming up with are reasonable,” said Michael Jerrett, professor of environmental health science at the University of California, Los Angeles who was not involved in the study. “We need more of them. It’s only if we’re doing multiple studies with many different designs that we gain scientific confidence of our outcomes.”
“These are real lives” being lost due to wildfire smoke
The paper’s researchers focused on deaths linked to chronic exposure to fine particulate matter, or PM2.5 — the main concern from wildfire smoke.
These particles can lodge deep into lungs and enter the bloodstream. Short-term exposure can trigger coughing and itchy eyes, but longer term, they can make existing health problems worse and lead to a range of chronic and deadly health issues, including respiratory illness, cardiovascular and neurological diseases, and premature death.
“Wildfire smoke PM2.5 has emerged as significant environmental hazard in the U.S., and it’s driven by increasing frequency and intensity of wildfires due to climate change,” said Min Zhang, a postdoctoral student at the Icahn School and a study author.
Along with decades of forest mismanagement, growing development in fire-prone areas has expanded the “urban wildland interface,” increasing wildfire risk with real consequences for human health, said Jerrett.
“Nobody’s going to have ‘wildfire death’ on their death certificate unless the fire actually burned them or a tree fell on them or something like that,” said Jerrett. “But many of the people that are dying from this exposure are ones that are already more vulnerable. These are real lives that are being lost. This is not some arbitrary abstract statistical concept.”
The fires that ravaged Los Angeles in 2025 likely were deadlier than initially estimated, according to research published last August. In that study, researchers analyzed data on the number of deaths in Los Angeles County from Jan. 5 to Feb. 1, 2025 — the period when the Palisades and Eaton fires tore through the city — and estimated that 440 more deaths could be attributed to the fires, compared to the expected number based on data from previous years.
A firefighter douses flames during the Eaton fire in Pasadena, California on January 08, 2025. JOSH EDELSON/AFP via Getty Images
A 2024 study estimated tens of thousands of people in California died premature deaths due to wildfire smoke from 2008 to 2018.
That study estimated 2,305 people died from PM2.5 exposure in Sonoma County from 2008 to 2018 due to wildfire smoke, CBS News Bay Area reported. The study also estimated 2,231 deaths in Santa Clara County, 2,063 deaths in Contra Costa County, and 2,057 deaths in Alameda County.
How researchers approached the study
The study’s authors analyzed the link between annual average exposure to PM2.5 from wildfire smoke and deaths by county in the lower 48. They used federal mortality data across 3,068 counties of all causes of death and several specific ones — circulatory, neurological and respiratory diseases, as well as mental and behavioral disorders, tumors and endocrine, nutritional and metabolic diseases.
They also included deaths related to falls and transport accidents — which are unlikely to be linked to wildfire smoke — to ensure their other observations weren’t biased.
“We found no association for car accidents and falls, while for other diseases we found statistically significant effects,” said Wei. Deaths from neurological diseases saw the biggest increase with exposure to these particulates.
How pronounced the link was between particulate exposure and death varied by season and demographics. A stronger association appeared during cooler periods, and people in rural areas and younger communities appeared to be more vulnerable.
Researchers also found that with every 0.1 microgram per cubic meter increase of PM2.5 across all these places, about 5,594 more people died each year.
Jerrett said the study had the benefit of a large study population and that it includes most causes of deaths in the U.S. But he said the county-level data could have led to over or underestimates because wildfire smoke is very dynamic. “It doesn’t just blanket a large county all at once. There are going to be parts of the county that gets it a lot worse.”
The study also did not account for other important factors, such as whether a person smokes, he said.
Rollbacks on climate policy pose risks, authors say
Kai Chen, an associate professor of environmental sciences at the Yale School of Public Health who has also studied the topic, said: “I really like that they examined both the smoke and nonsmoke PM2.5.” Various research has found that PM2.5 from wildfire smoke has bigger health impacts than pollution from other sources, such as car emissions, said Chen in an email, who was not involved in the study.
The Trump administration’s rollbacks in climate change policy, even as the more destructive wildfires become more frequent in large part due to global warming, poses critical risks, the study’s authors said. Quantifying the deadly threat that PM2.5 from wildfires poses to human health shows the need for effective, urgent mitigation strategies, backed by Environmental Protection Agency monitoring and regulation, they said.
“This highlights the importance of controlling wildfire sourced PM2.5, which is currently not regulated by the EPA as it is usually regarded as natural disasters,” Chen agreed.