California wildfire smoke linked to increased autism diagnoses, new study finds<\/p>\n
Children born to mothers who were exposed to smoke in southern California showed increased rates of autism, although the reason why is unclear<\/p>\n
By Jackie Flynn Mogensen<\/a> edited by Claire Cameron<\/a><\/p>\n Svetlana Repnitskaya via Getty Images<\/p>\n A new study of more than 200,000 children in southern California found a link between exposure to wildfire smoke in mothers and higher rates of autism in children. The causes of autism are not fully known and likely multifaceted, but the new research builds on existing evidence that air pollution may be tied to autism.<\/p>\n The study, published<\/a> on Tuesday in Environmental Science & Technology, analyzed data for children born in the wildfire hot spot from 2006 to 2014. Pregnant women who were in their third trimester and exposed to as few as one to five smoke days were about 11 percent more likely to have a child who was diagnosed as autistic by age five than those who saw no smoke days. The more smoke days that mothers were exposed to, the higher the likelihood that their children would be diagnosed as autistic: women who were exposed to between six and 10 smoke days were 12 percent more likely to have a child who received such a diagnosis by age five, while this was 23 percent more likely among those who were exposed to more than 10 smoke days.<\/p>\n \u201cThis is one of the first large population-based studies to specifically examine prenatal wildfire smoke exposure and autism risk,\u201d says Mostafijur Rahman, an assistant professor of environmental health sciences at Tulane University and an author of the new study. \u201cOur findings suggest that wildfire smoke exposure during sensitive periods of pregnancy\u2014particularly late pregnancy\u2014may be associated with an increased risk of autism diagnosis in children.\u201d<\/p>\n On supporting science journalism<\/p>\n If you’re enjoying this article, consider supporting our award-winning journalism by subscribing<\/a>. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.<\/p>\n Importantly, the study doesn\u2019t identify a direct causal link between autism and wildfire smoke, Rahman says. Most experts believe autism is complex and likely arises from a combination of environmental and genetic factors<\/a>.<\/p>\n Rather the study \u201chighlights wildfire smoke as a potentially modifiable environmental risk factor that may contribute to risk in combination with other factors,\u201d he says.<\/p>\n The study has several limitations. Some mothers included in the study may have had different levels of exposure to smoke than the researchers\u2019 estimated. And wildfires can also be extremely stressful\u2014an experience that may have also played a role.<\/p>\n David Mandell, a professor of psychiatry at the University of Pennsylvania who was not involved in the study, says that the paper\u2019s association between wildfire smoke and autism is \u201ccertainly concerning\u201d and \u201cworthy of further attention.\u201d<\/p>\n Mandell notes, however, that some children of mothers who experienced higher concentrations of wildfire smoke in her third trimester and didn\u2019t move house during the study period didn\u2019t show higher rates of autism\u2014which is not the \u201cdose-response gradient that one might expect,\u201d he says.<\/p>\n Autism and its causes have been a central focus of the Trump administration and Secretary of Health and Human Services Robert F. Kennedy, Jr., who has, in the past, claimed<\/a> that autism was most likely caused by a variety of environmental exposures, not all of which have been backed by solid science. According to the U.S. Centers for Disease Control and Prevention, around one in 31 children<\/a> are diagnosed as autistic before age nine.<\/p>\n The new study jibes with past research showing children whose mothers were exposed to high rates of fine particulate pollution<\/a>, as well as diesel exhaust and mercury<\/a>, were more likely to be diagnosed as autistic than the children of those who breathed cleaner air.<\/p>\n Wildfires have become an ever-present risk in the U.S., especially for Californians. According to<\/a> the U.S. Department of Agriculture, between 2003 and 2012, individual large wildfires in the western U.S. burned for an average of 52 days, up from just six days in the 1970s and 1980s.<\/p>\n \u201cAs wildfires become more frequent and intense due to climate change, understanding their potential long-term health impacts is increasingly important,\u201d Rahman says.<\/p>\n It\u2019s Time to Stand Up for Science<\/p>\n If you enjoyed this article, I\u2019d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.<\/p>\n I\u2019ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.<\/p>\n If you subscribe to Scientific American<\/a>, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.<\/p>\n In return, you get essential news, captivating podcasts<\/a>, brilliant infographics, can’t-miss newsletters<\/a>, must-watch videos, challenging games<\/a>, and the science world’s best writing and reporting. You can even gift someone a subscription<\/a>.<\/p>\n There has never been a more important time for us to stand up and show why science matters. I hope you\u2019ll support us in that mission.<\/p>\n","protected":false},"excerpt":{"rendered":"January 21, 2026 3 min read Add Us On GoogleAdd SciAm California wildfire smoke linked to increased autism…\n","protected":false},"author":2,"featured_media":142967,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[7,9,8],"class_list":{"0":"post-142966","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-california","8":"tag-california","9":"tag-california-headlines","10":"tag-california-news"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts\/142966","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/comments?post=142966"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts\/142966\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/media\/142967"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/media?parent=142966"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/categories?post=142966"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/tags?post=142966"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"wildfire\"](\"https:\/\/www.newsbeep.com\/us-ca\/wp-content\/uploads\/2026\/01\/1768990930_715_wildfire.jpg\")
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