{"id":27454,"date":"2025-08-10T11:40:28","date_gmt":"2025-08-10T05:55:28","guid":{"rendered":"https:\/\/www.revoscience.com\/en\/?p=27454"},"modified":"2025-08-10T11:51:22","modified_gmt":"2025-08-10T06:06:22","slug":"how-wildfire-smoke-exacerbates-ozone-pollution","status":"publish","type":"post","link":"https:\/\/www.revoscience.com\/en\/how-wildfire-smoke-exacerbates-ozone-pollution\/","title":{"rendered":"How wildfire smoke exacerbates ozone pollution"},"content":{"rendered":"\n
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The plume from the 2020 Loyalton fire on Northern California\u2019s Mount Ina Coolbrith near the town of Calpine on Aug. 15, 2020. This lightning-triggered fire burned 47,000 acres in the Tahoe and Humboldt-Toiyabe national forests. IMAGE: Duncan Kennedy<\/sup><\/em><\/figcaption><\/figure>\n\n\n\n

Wildfires release vast amounts of visible pollutants into the atmosphere that darken skies and push people indoors to avoid unhealthy air. But a near-invisible threat to public health associated with wildfires is\u00a0ozone, the reactive oxygen molecule\u00a0O\u2083\u00a0that harms the lungs and other sensitive tissues in the human body.<\/p>\n\n\n\n

New research led by the University of Utah documents how smoke from the West\u2019s wildfires substantially increases ozone concentrations, often above federal health standards, even in remote places with few human emission sources of ozone\u2019s precursor pollutants, such as nitric oxides, or NOx<\/a>.<\/p>\n\n\n\n

\u201cThe question I wanted to ask was, if we don\u2019t have urban emissions\u2014let\u2019s say that we zero out all emissions\u2014will we still have an ozone problem?\u201d said lead author\u00a0Derek Mallia<\/a>, a research assistant professor of atmospheric sciences. \u201cThis study suggests that we could remove all of the regional emissions from anthropogenic sources of NOx, but fires can still produce a large amount of ozone.\u201d<\/p>\n\n\n\n

Published last month in the journal Atmospheric Environment<\/em>, this research<\/a> highlights the double dose of air pollution in areas downwind from the flames, with high levels of both fine particulate matter and ozone. It is estimated that smoke exposure results in 6,300 deaths a year in the United States.<\/p>\n\n\n\n

Complicating this picture is the fact that ozone is not released directly into the air; rather, it forms in the atmosphere when oxygen atoms from other pollutants recombine in a photochemical process involving sunlight.<\/p>\n\n\n\n

The main drivers are NOx and volatile organic compounds, or VOCs<\/a>; the latter is a major component of wildfire smoke. NOx, on the other hand, is more associated with anthropogenic emission sources, such as vehicle tailpipes and industrial smokestacks.<\/p>\n\n\n\n

Ozone levels are very difficult to model because the pollutant is controlled by so many factors, including wind speed and direction, temperature, cloud cover, and time of day.<\/p>\n\n\n\n

To better understand the complicated relationship between smoke and ozone, Mallia\u2019s team applied coupled computer models, known as\u00a0WRF-Sfire<\/a>\u00a0and\u00a0WRF-Chem<\/a>, to a record-setting smoke event in 2020 that affected much of the Western United States. <\/p>\n\n\n\n

The period of Aug. 15-26 was among the West\u2019s worst fire episodes in the modern era. California\u2019s\u00a0August Complex fire<\/a>\u00a0burned more than 1 million acres across seven northern counties, causing $12 billion in damage. Dozens of fires raged elsewhere, such as Utah\u2019s 90,000-acre East Fork fire and Oregon\u2019s Lionshead and Beachie Creek fires that burned a combined 400,000 acres.<\/p>\n\n\n\n

The research concluded that, on average, the presence of wildfire smoke increases ozone concentrations by 21 parts per billion (ppm). \u201cOzone was roughly 20 to 30% higher because of wildfire smoke,\u201d Mallia said. \u201cThat\u2019s pretty big.\u201d<\/p>\n\n\n\n

Since background ozone levels in the West are already elevated, this added load potentially pushes levels beyond the 70-ppb health standard set by the U.S. Environmental Protection Agency<\/a>.<\/p>\n\n\n\n

To complicate things further, the research found that the shading from the smoke itself alters the weather and slows ozone formation, reducing levels by up to 10 ppb within the plume.<\/p>\n\n\n\n

\u201cYou also have a lot of particulate matter, which is a pollutant, too, but it can block sunlight, and therefore that will reduce the amount of sunlight available for ozone photochemistry. It can be substantial in some cases,\u201d Mallia said.<\/p>\n\n\n\n

\u201cIf you\u2019re right over the fire, there\u2019s usually enough smoke shading that it limits the amount of ozone. But if you get far enough away and the plume becomes relatively diffuse, it\u2019s usually not thick enough to really limit ozone.\u201d<\/p>\n\n\n\n

The study\u2019s key takeaway is that existing models should be improved as wildfires become more frequent and severe as the climate warms. Tools such as the WRF-Sfire and WRF-Chem models will be essential for predicting air quality and protecting public health during wildfire season\u2014but these tools need ongoing refinement to handle complex smoke dynamics.<\/p>\n","protected":false},"excerpt":{"rendered":"

Wildfires release vast amounts of visible pollutants into the atmosphere that darken skies and push people indoors to avoid unhealthy air.<\/p>\n","protected":false},"author":2,"featured_media":27455,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15],"tags":[],"class_list":["post-27454","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-environment"],"featured_image_urls":{"full":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine.webp",700,525,false],"thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine-200x200.webp",200,200,true],"medium":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine-675x506.webp",675,506,true],"medium_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine.webp",700,525,false],"large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine.webp",700,525,false],"1536x1536":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine.webp",700,525,false],"2048x2048":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine.webp",700,525,false],"ultp_layout_landscape_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine.webp",700,525,false],"ultp_layout_landscape":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine.webp",700,525,false],"ultp_layout_portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine-600x525.webp",600,525,true],"ultp_layout_square":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine-600x525.webp",600,525,true],"newspaper-x-single-post":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine-700x490.webp",700,490,true],"newspaper-x-recent-post-big":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine-550x360.webp",550,360,true],"newspaper-x-recent-post-list-image":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine-95x65.webp",95,65,true],"web-stories-poster-portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine-640x525.webp",640,525,true],"web-stories-publisher-logo":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine-96x96.webp",96,96,true],"web-stories-thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2025\/08\/Loyalton_Fire_from_near_Calpine-150x113.webp",150,113,true]},"author_info":{"info":["RevoScience"]},"category_info":"Environment<\/a>","tag_info":"Environment","comment_count":"0","_links":{"self":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/27454","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/comments?post=27454"}],"version-history":[{"count":2,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/27454\/revisions"}],"predecessor-version":[{"id":27458,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/27454\/revisions\/27458"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media\/27455"}],"wp:attachment":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media?parent=27454"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/categories?post=27454"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/tags?post=27454"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}