--- title: Why Extreme Heat Plus Pollution Is a Deadly Combination description: Research shows that the combined mortality risk of extreme temperatures and air pollution is more than the sum of their individual effects. canonical: https://time.com/6201615/heat-pollution-health-risk/ author: Emily Barone article:opinion: false article:content_tier: free article:published_time: 2022-07-28T17:51:15.000Z article:modified_time: 2026-10-14T09:38:00.450Z article:section: Climate og:title: Why Extreme Heat Plus Pollution Is a Deadly Combination og:description: The combined risk of death from extreme temperatures and air pollution is more than the sum of their individual effects og:url: https://time.com/6201615/heat-pollution-health-risk/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltdcf5e61fd04922aa/698a342809208ff62241964b/GettyImages-1241980535.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 og:image:width: 5720 og:image:height: 3218 og:image:alt: TOPSHOT-FRANCE-WILDFIRES-TOURISM-HEAT og:type: article twitter:card: summary_large_image twitter:title: Why Extreme Heat Plus Pollution Is a Deadly Combination twitter:description: The combined risk of death from extreme temperatures and air pollution is more than the sum of their individual effects twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltdcf5e61fd04922aa/698a342809208ff62241964b/GettyImages-1241980535.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 video:duration: 01:25 video:published: 2022-07-14 section: climate topics: climate change, heat waves, public health, vulnerable populations, climate policy, public education, climate models, extreme weather genre: news, explainer tones: urgent, cautionary, serious, informative emotions: concern (high), urgency (medium), caution (medium) sentiment: negative audience: general news readers, public health officials, policymakers, climate-concerned viewers content_suitability: health controversy [00:00-00:07]; disasters [00:43-01:03] transcript_source: automatic transcription transcript_reviewed: not applicable ---  # Why Extreme Heat Plus Pollution Is a Deadly Combination > Sponsored content. 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Future Proof is TIME's weekly climate and energy newsletter, written by senior correspondent Justin Worland. It connects the energy transition to the decisions reshaping business, technology, policy and markets. #### Where can I follow the energy transition as a business story? Future Proof covers climate and energy as an economic and business story rather than only an environmental one. It publishes every Friday and is free at time.com/newsletters. #### Who writes Future Proof? Justin Worland, a senior correspondent at TIME and an award-winning climate journalist, writes Future Proof. #### Is Future Proof free? Yes. Future Proof is free at time.com/newsletters. ### Sources * TIME Newsletters: [time.com/newsletters](/c/time-nl-futureproof-2026q3/newsletters?i=6630883a-f2b4-4fd2-adb7-49fe33116d2b&cr=time-nl-futureproof-2026q3-v1) ## Video: How Heat Waves Could Have Long-Term Impacts on Your Health [Watch (HLS stream): How Heat Waves Could Have Long-Term Impacts on Your Health](https://cdn.jwplayer.com/manifests/Xc0OjO7C.m3u8) (1:25)  _Published 2022-07-14. Health officials from the U.S., the U.K., Europe, and Japan have been warning residents to stay out of the sun as the northern hemisphere experiences some of the highest early summer temperatures ever recorded. It’s not just to prevent heat-stroke, but to prevent the long-term consequences as well._ Description, summary, key points, chapters, key quotes, questions and transcript, where present, were produced automatically from the video or its captions and were not reviewed. ## Summary The video argues that climate change is real and that heat waves are becoming more frequent, prolonged and intense. It stresses the need to prepare through policy and public education. It highlights particular risk to vulnerable groups such as the very elderly and very young babies, and notes that the duration of heat waves matters as well as peak temperatures. ## Key points - Climate change is real, and society needs to change its mindset and prepare for these new kinds of events. (00:00) - Heat waves will become more and more frequent, and preparation is needed in both policymaking and in teaching people how to deal with them. (00:24) - High heat levels can have real-world impacts, especially on vulnerable people such as the very elderly and very young babies. (00:43) - The duration of heat waves matters as much as the high temperatures expected in the coming weeks. (00:50) - Heat waves have become more frequent, more prolonged, and their peak temperatures have been higher. (01:08) - Climate models predict heat waves will become more frequent, more prolonged and more intense over the next few decades. (01:16) ## Chapters - [00:00 to 00:24] Climate change is real. The speaker says climate change is not fake news and calls for a change in mindset and preparation. - [00:24 to 00:43] Preparing for more frequent heat waves. The speaker explains that heat waves will become more frequent and that policies and public education must adapt. - [00:43 to 01:03] Impacts on vulnerable people. The speaker describes the health risks heat poses to the very elderly and very young babies, particularly during prolonged heat waves. - [01:03 to 01:25] Heat waves are intensifying. The speaker explains that heat waves have become more frequent, prolonged and intense, as climate models predict will continue. ## Key quotes - [00:00] Speaker: "The climate change is not fake news. They are here, they are for real and we need to really change our mindset and prepare ourselves for these new kind of events." - [00:24] Speaker: "Hwaves will become more and more frequent and we do need to prepare not only in terms" - [00:43] Speaker: "the kinds of impacts these levels of heat can have particularly on vulnerable people" - [01:16] Speaker: "That's what climate models predict going through the next few decades is that heat waves will become more frequent, more prolonged and more intense." ## Questions this video answers - Are heat waves becoming more frequent? [00:24] - Who is most at risk from heat waves? [00:43] - Why does the duration of a heat wave matter? [00:50] - What do climate models predict for heat waves in the coming decades? [01:16] - What needs to change in response to more frequent heat waves? [00:29] ## Content suitability - health controversy [00:00-00:07]: The speaker refers to climate change being called fake news, a contested claim. - disasters [00:43-01:03]: Discusses heat waves causing real-world health impacts, especially on vulnerable people. by [Emily Barone](https://time.com/author/emily-barone/) ## Emily Barone Jul 28, 2022 5:51 PM UTC Health officials from the U.S., the U.K., Europe, and Japan have been warning residents to stay out of the sun as the northern hemisphere experiences some of the highest early summer temperatures ever recorded. It’s not just to prevent heat-stroke, but to prevent the long-term consequences as well. by [Emily Barone](https://time.com/author/emily-barone/) ## Emily Barone Jul 28, 2022 5:51 PM UTC Two climate-related health risks are converging with alarming frequency: record high temperatures, and air pollution from things like car exhaust and wildfire smoke. Separately, these conditions can [make people acutely sick](https://time.com/6186988/extreme-heat-human-body-impact/) and [exacerbate existing health problems](https://time.com/6196564/climate-change-obesity-long-term-health-impacts/). But what happens when they coincide? Recently, researchers at the University of Southern California set out to answer that question. Their results, based on mortality data from California between 2014 and 2019 and published at the end of June in the [_American Journal of Respiratory and Critical Care Medicine_](https://www.atsjournals.org/doi/epdf/10.1164/rccm.202204-0657OC), indicate that the combined mortality risk of extreme temperatures and thick pollution is significantly more than the sum of their individual effects. As the chart below shows, a person’s odds of dying increased 6.1% on extreme temperature days and 5% on extreme pollution days compared with non-extreme days. But on days with both extreme conditions, the risk of death jumped by 21%. Like vehicle emissions, wildfires release PM2.5, a type of very fine particulate matter that measures less than 2.5 micrometers across. (For comparison, the diameter of a hair is 30 times larger than the largest of these fine particles.) While the USC researchers analyzed PM2.5 pollution levels regardless of its source, they found that days with extremely high pollution happened to coincide with California wildfire events. “When you consider our top 1% of most polluted days, the pollution concentration is really very, very high… four times higher \[than normal\],” says Md Mostafijur Rahman, a postdoctoral researcher in the Department of Population and Public Health Sciences at USC’s Keck School of Medicine and one of the study’s co-authors. “That is definitely driven by another source. It’s not like the normal source from the traffic.” Fine particulate matter can penetrate deep into the lungs and enter the bloodstream, says Francesca Dominici, a biostatistics professor at Harvard’s T.H. Chan School of Public Health who has studied the noxious stuff. But, while PM2.5 is known to cause [cardiovascular diseases, respiratory problems, and cancers](https://www.who.int/news-room/fact-sheets/detail/ambient-%28outdoor%29-air-quality-and-health), some forms of it are worse than others. “Fine particulate matter during wildfires tends to be even more toxic,” Dominici says. “We have buildings burning, we have cars burning, we have all kinds of stuff that is burning. There is emerging research to show that the chemical composition is even more dangerous.” What’s more, when those tiny particles [react with high temperatures and sunlight](https://www.epa.gov/ground-level-ozone-pollution/ground-level-ozone-basics#formation), they can [worsen ground-level ozone](https://sitn.hms.harvard.edu/flash/2022/a-deadly-mix-wildfires-and-urban-air-pollution-create-toxic-ozone/)—smog—which can trigger [respiratory effects ](https://www.epa.gov/ground-level-ozone-pollution/ground-level-ozone-basics#formation)like asthma attacks. One [study](https://www.science.org/doi/10.1126/sciadv.abi9386) from Washington State University published earlier this year found that periods of high ​​PM2.5 and ozone have “become significantly more frequent and persistent” across the western U.S. in the last 20 years, due to “simultaneous widespread heat and wildfire activity.” A notable 12-day stretch in the summer of 2020 included one August day where nearly 70% of that region—encompassing 43 million people—was affected by harmful levels of air pollution due to unprecedented wildfire activity around that time. Make no mistake, though. The American West is certainly not the only place grappling with the double threats of heat and pollution. Extreme temperatures have touched just about every corner of the country this summer, and fires are searing through forests as far north [as Alaska](https://earthobservatory.nasa.gov/images/150056/a-smoky-summer-in-alaska). Eastern Australia, known for its hot summers and dangerous bushfires, had an historically devastating 2019-2020 season. Russia experienced one of its [largest wildfires on record ](https://www.theguardian.com/world/2021/sep/22/russia-forest-fire-damage-worst-since-records-began-says-greenpeace)last year in Siberia amid hot and dry conditions. In Europe, infernos ravaged Turkey and Greece last year; this year they’re sweeping through [Spain and France](https://www.theguardian.com/world/2022/jul/25/wildfires-continue-to-burn-across-france-and-spain), fueled by heat waves that smashed records for both [how early in the year](https://time.com/6190496/heat-waves-summer-2022-starting-early/) they appeared and [how high the mercury rose](https://time.com/6198905/uk-heat-climate-change-politics/). This confluence of events during summer months, when temperatures soar to unbearable levels [that our bodies cannot handle](https://time.com/6186988/extreme-heat-human-body-impact/), are becoming more common: The heat waves make dry regions even drier—and ideal for wildfires which spew smoke plumes [far and wide](https://www.nature.com/articles/s41598-022-16607-3). Erika Garcia, assistant professor in the Department of Population and Public Health Sciences at USC’s Keck School of Medicine who co-authored the study with Rahman, warns that even though wildfires are episodic, their effects can last for weeks. “With climate change progression, we will continue to experience more frequent, more intense, and longer extreme heat events, and extreme particulate pollution events,” she says. “We really need to have better interventions and adaptation policies so that we can save lives during these extreme heat and pollution days.” ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/6201615/heat-pollution-health-risk/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/6201615/heat-pollution-health-risk/"},"headline":"Why Extreme Heat Plus Pollution Is a Deadly Combination","datePublished":"2022-07-28T17:51:15.000Z","dateModified":"2026-10-14T09:38:00.450Z","description":"Research shows that the combined risk of death from extreme temperatures and air pollution is more than the sum of their individual effects","url":"https://time.com/6201615/heat-pollution-health-risk/","keywords":["extreme weather","climate change","climate","healthscienceclimate"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/bltdcf5e61fd04922aa/698a342809208ff62241964b/GettyImages-1241980535.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"Emily Barone","jobTitle":null,"url":"https://time.com/author/emily-barone/"}],"articleSection":"Climate","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/bltdcf5e61fd04922aa/698a342809208ff62241964b/GettyImages-1241980535.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"TOPSHOT-FRANCE-WILDFIRES-TOURISM-HEAT","caption":"Smoke rises from a forest fire behind beachgoers in Arcachon, France, on July 18, 2022, when temperatures topped 100° F.","creditText":"Thibaud Moritz—AFP/Getty Images","representativeOfPage":true}],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"https://time.com/section/climate/","name":"Climate"}},{"@type":"ListItem","position":2,"item":{"@id":"https://time.com/tag/extreme-weather/","name":"extreme weather"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/6201615/heat-pollution-health-risk/","name":"Why Extreme Heat Plus Pollution Is a Deadly Combination"}}]},{"@context":"https://schema.org","@type":"VideoObject","name":"How Heat Waves Could Have Long-Term Impacts on Your Health","description":"Health officials from the U.S., the U.K., Europe, and Japan have been warning residents to stay out of the sun as the northern hemisphere experiences some of the highest early summer temperatures ever recorded. 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