For 49 straight days, everyone in Seeley Lake was breathing smoke. A wildfire had ignited outside the small rural community in Montana, and the plume of smoke had parked itself over the houses. Air quality plummeted. At several moments, the concentration of particulate matter in the air exceeded the upper limit of what monitors could measure.
连续49天，Seeley Lake的每个人都在呼吸烟。一场野火在蒙大拿州的小型农村社区外被点燃，烟羽停在房屋上。空气质量暴跌。在片刻中，空气中颗粒物的浓度超过了监视器可以测量的上限。
Christopher Migliaccio, an associate professor of immunology at the University of Montana, saw an opportunity to do what few have ever done: study what happens after people get exposed to wildfire smoke. He and his team quickly cobbled together funding and drove out to Seeley Lake to get data.
蒙大拿大学免疫学副教授克里斯托弗·米格里亚西奥（Christopher Migliaccio）看到了一个曾经做过的事情的机会：研究人们暴露于野火烟雾后会发生什么。他和他的团队迅速将资金拼凑在一起，开车去Seeley Lake获取数据。
That was in 2017. The researchers followed up with residents for two years after the fires, checking on their lung function. To their surprise, the worst effects didn’t show up immediately, despite the heavy dose of smoke. Instead, people’s lung function seemed to deteriorate later. Right after the fires, about 10 percent of the cohort had lung function that fell below the lower limit of normal. By the one-year mark, about 46 percent did. At the two-year mark, most of those people still had abnormally poor lung function. “We were very surprised,” Migliaccio told me. He and his colleagues had intended to follow the residents for a third year, but then COVID hit. Instead, they tried exposing mice to wildfire smoke in a controlled lab environment. Their results pointed to a similar outcome: The worst effects took time to present.
那是在2017年。研究人员在大火后跟进了居民两年，检查了他们的肺功能。令他们惊讶的是，尽管有大量烟雾，但最坏的影响并未立即出现。取而代之的是，人们的肺功能似乎在后来恶化。火灾发生后，大约10％的队列具有肺功能低于正常的下限。到一年，大约有46％的人做到了。在为期两年的时间里，大多数人的肺部功能异常差。“我们感到非常惊讶，”米格里亚西奥告诉我。他和他的同事打算跟随居民第三年，但随后遭受了袭击。取而代之的是，他们尝试在受控的实验室环境中暴露小鼠在野火中烟雾。他们的结果表明了类似的结果：最坏的效果花了一些时间。
Migliaccio’s work can speak to only a single smoke event. But it is the type of event that more people in the United States are dealing with, over and over again. Until recently, wildfires that exposed large populations to smoke were a relatively rare occurrence. But that’s changing: More frequent and intense wildfires are erasing or even reversing decades of gains made in American air quality in the majority of U.S. states. Across the country, from 2012 to 2022, the number of people exposed to unhealthy air from wildfire smoke increased 27-fold; one out of every four unhealthy air days in parts of the country is now a smoke day. “It is the exposure that is impacting air quality across the U.S. now more than any other pollution source,” Joan Casey, an environmental epidemiologist at the University of Washington whose work helped show a link between wildfire-smoke exposure and increased risk of dementia, told me.
Migliaccio的作品只能与一次烟雾事件交谈。但是，这是美国越来越多的人一次又一次地打交道的事件。直到最近，暴露于大量烟雾的野火还是相对罕见的。但这正在发生变化：在大多数美国州，美国空气质量的增长数十年，更频繁，更激烈的野火正在擦除甚至颠倒了数十年的收益。从2012年到2022年，全国各地的野火烟雾不健康空气的人数增加了27倍；现在，该国部分地区每四个不健康的空气日中有一个是烟一天。华盛顿大学的环境流行病学家琼·凯西（Joan Casey）告诉我：“正是影响美国的空气质量比任何其他污染源都更大。”
Yet science—to say nothing of policy—has hardly caught up with what that means for human health. “We’re in the preschool stage of development,” Casey said. What cumulative smoke exposure can do to a body and mind remains largely a mystery, but the few studies that do exist point to nothing good.
然而，科学对政策的说法一无所知 - 几乎没有抓住这对人类健康的意义。凯西说：“我们正处于发展的阶段。”累积的烟雾暴露会对身心造成的影响仍然是一个谜，但确实存在的少数研究表明没有任何好处。
Plenty of research shows that respiratory distress and heart attacks spike in the event of smoke exposure; acute impacts of breathing smoke send people to the hospital and make them miss work and school. Those risks can linger for months afterward, or, in the case of the Seeley Lake cohort, for years.
大量的研究表明，如果烟雾暴露，呼吸窘迫和心脏病发作激增。呼吸烟雾的急性影响使人们去医院，让他们失踪和学校。这些风险可能会在几个月后持续使用，或者在Seeley湖队列中多年。
Now that more people are regularly breathing smoky air over their lifetime, though, the relevant concern may no longer be what happens when a person gets one big dose of smoke; rather, it may be what happens when they are exposed many times. How much does anyone know about the long-term consequences of exposure to smoke or, worse, the long-term consequences of long-term exposure to smoke? “Very little,” Marianthi-Anna Kioumourtzoglou, an environmental engineer and epidemiologist at—as of next week—Brown University, told me.
现在，越来越多的人会在他们的一生中呼吸烟熏空气，但是，当一个人散发一大剂量的烟雾时，相关的担忧可能不再是会发生什么。相反，这可能是当他们多次暴露时会发生什么。有人知道暴露于烟雾的长期后果，或者更糟糕的是，长期暴露于烟雾的长期后果？“很少，”玛丽安·安娜·库莫尔·佐格洛（Marianthi-Anna Kioumourtzoglou）是棕色大学的环境工程师和流行病学家告诉我的。
The best model for assessing wildfire-smoke exposure was developed only recently, Kioumourtzoglou and Casey told me, and, because of satellite imagery and monitoring limitations, goes back to only 2006. That means researchers have at most 20 years of data to look at in determining whether smoke could have contributed to a population’s incidence of a particular illness. Latency periods for plenty of diseases, including some cancers, can be longer. Plus, every fire is its own unique nightmare, chemically speaking. The Seeley Lake fire burned mostly trees. Add to that whole neighborhoods of cars and houses and parking lots, and the toxicity profile of the smoke changes significantly. During the Los Angeles fires in January, which burned down entire neighborhoods, noxious compounds from burning plastics and other man-made materials swirled through the air.
Kioumourtzoglou和Casey告诉我，评估野火 - 烟雾曝光的最佳模型才开发出来，并且由于卫星图像和监测局限性，它可以追溯到2006年。这意味着研究人员在确定烟雾时最多有20年的数据有助于人们的特定疾病的发生率。包括一些癌症在内的大量疾病的潜伏期可能更长。另外，从化学上讲，每场大火都是自己独特的噩梦。Seeley Lake大火主要燃烧着树木。再加上整个汽车，房屋和停车场的社区，烟雾的毒性也发生了很大变化。在一月份的洛杉矶大火中，烧毁了整个社区，燃烧塑料和其他人造材料在空中旋转的有害化合物。
Scientists know a lot about the harms of regular ambient air pollution (such as the particulate matter that spews from tailpipes and factories), but wildfire smoke is chemically different—and likely worse, from a health standpoint. Its complexity is also daunting from a research perspective: Even the types of trees burned appear to affect the smoke’s toxicity. In a lab study, for instance, researchers burned peat, pine needles, and several types of wood to simulate different regional forests. They found that pinewood smoke was the most mutagenic, suggesting that it might be more likely to cause cancer than other woods, and that eucalyptus smoke was the most toxic to lungs. How long the smoke stays in the air may matter too. Some research suggests that smoke becomes more toxic as it ages, which is bad news for people living downwind from smoke—in parts of the U.S. during Canadian wildfires, for instance.
科学家对常规环境空气污染的危害（例如从尾管和工厂喷出的颗粒物）造成了很多了解，但是野火在化学上是不同的，并且从健康角度来看可能更糟。从研究的角度来看，它的复杂性也令人生畏：即使被燃烧的树木类型也影响了烟雾的毒性。例如，在一项实验室研究中，研究人员燃烧了泥炭，松针和几种类型的木材，以模拟不同的区域森林。他们发现，松木烟雾是最诱人的，这表明它可能比其他树林更有可能引起癌症，而桉树烟雾对肺部最有毒。烟雾在空中的时间也可能很重要。一些研究表明，随着年龄的增长，烟雾变得更加毒性，这对从烟雾中靠下风的人们（例如，在加拿大野火期间的美国地区）来说是个坏消息。
And unlike our relatively steady exposure to ambient air pollution, exposure to wildfire smoke is spiky, coming in bursts, with pauses in between. That makes it hard to model, Kioumourtzoglou told me, and also introduces many questions, each of which needs research attention: Is the health impact worse if a person breathes a very high level of smoke for three days, or if they breathe a lower level for three weeks? How does the point in life at which they are exposed—as an adult with asthma, a child whose lungs were still developing, a fetus in utero—change how the smoke affects them?
与我们相对稳定的环境空气污染的暴露不同，暴露于野火的烟雾是尖峰，爆发了，介于两者之间。Kioumourtzoglou告诉我，这很难建模，还引入了许多问题，每个问题都需要研究注意：如果一个人在三天内呼吸很高的烟雾，或者如果他们呼吸较低的水平三周，是否会更糟？他们暴露的生活点如何 - 作为哮喘的成年人，肺部仍在发育的孩子，子宫里的胎儿 - 改变烟雾对他们的影响如何？
Many of the attempts to even start to answer these questions depend on chance and the swift action of researchers like Migliaccio, who seize on the chance to study a fire close at hand. In the summer of 2008, for instance, Lisa Miller, who studies pulmonary immunology and toxicology at UC Davis, was in her office as wildfires sent smoke settling over the region. The air outside her office looked like thick winter fog. She suddenly thought about the rhesus monkeys she studied at the primate research center; they had been outside in their habitat the whole time. These primates were great models for human health, so they became a case study for what happens to a smoke-exposed body.
许多开始回答这些问题的尝试取决于机会，以及像Migliaccio这样的研究人员的迅速行动，他们抓住了靠近手头的大火的机会。例如，在2008年夏天，丽莎·米勒（Lisa Miller）在加州大学戴维斯（UC Davis）学习肺部免疫学和毒理学，当时野火在该地区散发烟雾而在她的办公室里。她办公室外面的空气看起来像浓雾浓密。她突然想到了她在灵长类动物研究中心学习的恒河猴。他们一直都在栖息地。这些灵长类动物是人类健康的绝佳模型，因此它们成为了暴露于烟雾身体发生的事情的案例研究。
Miller and her team studied the monkeys for the next 15 years. They found that those that were exposed to wildfire smoke as infants became adolescents with smaller, stiffer lungs than their peers born the following year, which resulted in poorer lung function and worse immune regulation. When the researchers exposed blood samples from both populations of adolescent monkeys to bacterial infection, the samples from the smoke-exposed animals responded more weakly, indicating that their immune system wasn’t working as well. The smoke-exposed monkeys also slept far less, she told me: “It was absolutely stunning.” Some research suggests that smoke can affect humans the same way: In 2022, a large study in China concluded that human children who had been exposed to air pollution early in life also had poorer-quality sleep. High-quality sleep is important to neurodevelopment in children, and poor sleep is associated with a range of negative health consequences across a lifetime.
米勒和她的团队在接下来的15年中学习了猴子。他们发现，那些暴露于野火烟雾的人，婴儿变成了比次年出生的同龄人更小，更硬的肺的青少年，这导致肺功能较差，免疫调节较差。当研究人员将两种青少年猴子种群的血液样本暴露于细菌感染中时，暴露于烟雾的动物的样本反应较弱，表明它们的免疫系统也无法正常工作。她告诉我：“这绝对令人惊叹。”一些研究表明，烟雾会以同样的方式影响人类：在2022年，一项大型研究得出结论，在生命早期暴露于空气污染的人类儿童的睡眠也较差。高质量的睡眠对儿童的神经发育很重要，睡眠不足与一生中的一系列负面健康后果有关。
What we can learn from Miller’s monkeys is limited; they spend 24 hours a day outdoors, unlike humans, and they get constant medical care and perfectly tailored diets, also unlike humans. Still, rhesus monkeys are some of the closest animals to us, physiologically, and on a basic level, smoke exposure in infancy seems to have affected these monkeys’ health for their entire life, Miller said.
我们可以从米勒的猴子那里学到的东西有限。与人类不同，他们每天在户外度过24个小时，并且与人类不同，他们不断获得医疗保健和完美量身定制的饮食。米勒说，尽管如此，在生理上，恒河猴还是与我们最近的动物，而且在基本水平上，婴儿期的烟雾似乎影响了这些猴子的一生。
Standard air pollution is known to have a negative impact on virtually all aspects of fertility, and for people who wish to conceive children, smoke may pose a hazard too. After wildfires in Oregon prompted an air-quality emergency in Portland in 2020, researchers looked at the sperm quality of 30 people who had their semen analyzed at a fertility clinic before and after the fires. The study was small, but the trend was clear: Motility—how well the sperm swims—went down for most of the participants. A nearly identical study in Seattle, which is still awaiting peer review, yielded a similar result. And Luke Montrose, an environmental toxicologist at Colorado State University, told me that he’s seen similar results in bull sperm: He and his colleagues got records from a cattle-breeding facility in Colorado that tests bull sperm with many of the same metrics used for human sperm at a fertility clinic. Sperm that isn’t up to shape gets discarded by the facility; after a wildfire in the area, more of the cattle sperm got thrown out, Montrose found. Quality must have gone down.
众所周知，标准空气污染对生育能力的几乎所有方面都有负面影响，对于希望怀孕的人，烟雾也可能造成危险。在俄勒冈州的野火促使2020年在波特兰发生了空中质量紧急情况之后，研究人员研究了大火前后在生育诊所进行了精液分析的30人的精子质量。这项研究很小，但趋势很明显：运动性 - 精子游泳好得多 - 大多数参与者都降低了。在西雅图仍在等待同行评审的一项几乎相同的研究产生了相似的结果。科罗拉多州立大学的环境毒理学家卢克·蒙特罗斯（Luke Montrose）告诉我，他在牛精子中看到了类似的结果：他和他的同事们从科罗拉多州的一家牛繁殖设施中获得了科罗拉多州的一家养牛场的记录，该记录测试了Bull Sperm，其中许多与人类精子相同的指标在生育临床上使用。没有造型的精子被设施丢弃；蒙特罗斯发现，在该地区发生了野火之后，更多的牛精子被扔掉了。质量一定已经下降。
The results on the bull sperm are preliminary and are awaiting peer review. But in the meantime, Montrose is enrolling male firefighters in a study to learn whether their fertility is affected by their job (which forces them to breathe much higher doses of smoke than the general population). When Montrose and his colleagues exposed mice to a very high dose of wood smoke in a lab—simulating what they estimate would be the equivalent of 15 years on the job for a wildland firefighter—the mouse sperm was significantly altered at the epigenomic level, where gene expression is altered without changing the underlying DNA sequence. “Normally, in a study like this, you see a handful of sites being changed,” Montrose told me; he and his colleagues found changes at more than 3,000 different sites, reflecting about 2,000 different genes. Montrose wonders what this far higher level means for the mice’s fertility and for their offspring. Whether these changes are positive or negative, it appears that smoke can alter, on a deep level, the very cells involved in reproduction. “It’s intriguing, but we still don’t quite know what it means,” Montrose said.
公牛精子的结果是初步的，并且正在等待同行评审。但是与此同时，蒙特罗斯（Montrose）正在招募男性消防员参加一项研究，以了解其生育能力是否受工作影响（这迫使他们呼吸比一般人群更高的烟雾剂量）。当蒙特罗斯（Montrose）和他的同事将小鼠暴露于实验室中很高的木烟中时，对野外消防员的估计，估计的估计等同于15年的工作 - 在表观基因组水平上，小鼠精子在基因表达中发生了显着改变，而基因的表达在不改变基础DNA序列的情况下会改变。“通常，在这样的研究中，您会看到一些网站正在改变，”蒙特罗斯告诉我。他和他的同事发现3,000多个不同地点的变化，反映了大约2,000个不同的基因。蒙特罗斯（Montrose）想知道这一较高水平对小鼠的生育能力和后代意味着什么。这些变化是正面的还是负的，似乎烟雾可以在深处改变涉及繁殖的细胞。蒙特罗斯说：“这很有趣，但我们仍然不知道这意味着什么。”
If smoke can affect health early in life, it also can affect life’s end. Breathing smoke can cause inflammation, which is a key pathway for many neurological disorders, and research is now turning up associations between smoke and conditions that strike older people, such as Parkinson’s, Casey told me. Smoke also causes premature death: more than 50,000 people in California died prematurely from wildfire smoke between 2008 and 2018, according to one estimate, and more than 11,000 people in the U.S. do so each year, according to another. Climate change is only accelerating those dynamics. As I’ve written before, the National Bureau of Economic Research found last year that in a worst-case warming scenario, deaths from wildfire-smoke exposure in the U.S. could top 27,000 a year by the middle of the century. That is, smoke could kill 700,000 people from now until 2055.
如果烟雾会影响生活的早期健康，它也会影响生命的尽头。呼吸烟可能会引起炎症，这是许多神经系统疾病的关键途径，现在的研究正在促进烟与帕金森（Parkinson's）等老年人的烟雾和疾病之间的关联，凯西告诉我。烟雾还导致过早死亡：根据一个估计，在2008年至2018年之间，加利福尼亚州有50,000多人因野火烟雾过早死亡，每年在美国有11,000多人这样做。气候变化只会加速这些动态。正如我之前写的那样，国家经济研究局去年发现，在最坏的速度变暖方案中，美国野火 - 烟熏曝光的死亡人数在本世纪中叶每年可能每年27,000。也就是说，从现在起到2055年，烟雾可能会杀死70万人。
Burning fossil fuels has locked us into a downward spiral: Warmer temperatures mean more fires. Already, summer 2025 is poised to be a fiery one in California, only half a year after fires devastated Los Angeles. Canada has already been burning for weeks, sending smoke billowing down through the U.S. The smoke is coming for us all—each of us is now more likely to encounter it in the coming years.
燃烧的化石燃料已将我们锁定在螺旋中：较高的温度意味着更多的火灾。2025年夏季，在加利福尼亚州遭到火灾仅半年，洛杉矶已经有一年的火热。加拿大已经燃烧了数周，使烟雾通过美国涌入烟雾。
That terrible reality means that researchers will have more opportunities to understand what smoke does to us. Susan Cheng, a cardiologist at Cedars-Sinai Medical Center, in Los Angeles, is now part of a major multi-institutional study of people exposed to the L.A. fires. As a cardiologist, she’s well aware of the extreme heart risks associated with smoke inhalation. Breathing regular pollution over a long period can accelerate heart disease by prematurely aging blood vessels and accelerating plaque buildup in the coronary artery; at least one recent study found that people’s risk of heart failure and other serious cardiac problems can persist for months after smoke exposure. If that’s any indication, fire smoke is a major heart hazard.
这种可怕的现实意味着研究人员将有更多机会了解烟雾对我们的影响。洛杉矶Cedars-Sinai医疗中心的心脏病专家Susan Cheng现在是暴露于洛杉矶大火的人的一项重大多机构研究的一部分。作为心脏病专家，她非常了解与吸入烟雾有关的极端心脏风险。长期呼吸常规污染可以通过过早衰老的血管和加速冠状动脉的斑块积聚来加速心脏病。至少有一项最近的研究发现，烟雾暴露后的几个月后，人们患心力衰竭和其他严重的心脏问题的风险。如果有任何迹象，火烟是一种严重的心脏危害。
“We really need to be closely tracking and following this,” Cheng told me. “Otherwise, we will be facing a major information gap, and trying to, in hindsight, put the pieces together.” She pictures asking, years down the line, “How did people get this way? How did our patients end up with these accelerated aging processes, accelerated development of these different chronic conditions?” Studies like hers—which began in January and will follow a cohort of more than 13,000 Angelenos for the next 10 years—aim to answer those questions now, before even more of the country starts having to ask them.
“我们真的需要密切跟踪并遵循这一点，”郑告诉我。“否则，我们将面临一个主要的信息差距，并在事后努力将这些碎片放在一起。”她的照片问，几年来，“人们是怎么做到的？我们的患者如何最终获得这些加速的衰老过程，加速了这些不同的慢性状况？”像她这样的研究（从1月开始），将在接下来的10年中遵循13,000多年的安吉伦诺斯人的同伙，现在要回答这些问题，然后在全国更多的国家开始不得不问他们之前。
