![\"Wildfires](\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2025\/06\/PM2.5-wildfires-1.jpg\")
<\/figure><\/div>\n\n\nWildfires Became the Biggest Source of Air Pollution in the Western U<\/strong>S<\/h3>\n\n\n\nFrom 2016 to 2021, researchers looked at air quality data in the Western U.S. across both smoke-filled and clean days. They found that wildfires now account for a surprisingly large part of total air pollution, especially in the summer.<\/p>\n\n\n\nWildfires were responsible for:<\/td> During fire season (July to September)<\/strong><\/td>Annually<\/strong><\/td><\/tr>PM2.5<\/strong><\/td>52-58%<\/td> 35-47%<\/td><\/tr> Carbon monoxide (CO)<\/strong><\/td>14-23%<\/td> 5-12%<\/td><\/tr> Ozone (O\u2083)<\/strong><\/td>10-19%<\/td> 6-13%<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nThat means, for much of the year, a third to nearly half of all fine particle pollution comes from fires, not cars or factories.<\/strong><\/p>\n\n\n\nSmoke Days vs. Clean Days<\/h3>\n\n\n\n
On smoke days, the average PM2.5 concentration shot up to 31 \u00b5g\/m\u00b3, compared to just 7 \u00b5g\/m\u00b3 on clean days. That\u2019s more than a fourfold increase, and enough to push many cities into the \u201cunhealthy\u201d AQI zone.<\/p>\n\n\n\n![\"Average](\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2025\/06\/wildfire-PM2.5_page-0002-scaled.jpg\")
<\/figure>\n\n\n\nThe study also looked at gases released during smoke days. Wildfires don\u2019t emit ozone directly. But they do release volatile organic compounds (VOCs)<\/strong> and NO\u2093<\/strong>, which then react in sunlight to form ozone. So the fires are indirectly boosting ground-level ozone, another lung irritant.
<\/p>\n\n\n\n![\"Average](\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2025\/06\/wildfire-PM2.5_page-0001-1024x576.jpg\")
<\/figure>\n\n\n\nParticle Size Changes With Wildfire<\/strong>s<\/h3>\n\n\n\nPM\u2082.\u2085, or particulate matter smaller than 2.5 micrometers (2,500 nanometers), is a common and harmful component of wildfire smoke. On clean days, the geometric mean diameter (GMD) of airborne particles is about 72 nanometers (nm). During smoky days, that number jumps to 139 nm.<\/p>\n\n\n
\n![\"Pm2.5,PM10](\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2023\/04\/\u63d2\u56fe-2.4.jpg\")
<\/figure><\/div>\n\n\nAt first glance, that might seem like an improvement, bigger particles must be less harmful, right? Not quite. Even at 139 nm, these particles are still ultrafine, far smaller than a human hair (which is around 75,000 nm thick).<\/p>\n\n\n\n
Both 72 nm and 139 nm particles are small enough to bypass your body\u2019s natural defenses, reach deep into the lungs (the bronchi and alveoli), and potentially enter the bloodstream. So no, the slightly larger size of wildfire smoke particles doesn\u2019t make them any safer. They\u2019re still firmly in the danger zone.<\/p>\n\n\n\n
Wildfires are no longer just seasonal hazards, they\u2019re now the dominant source of air pollution in the Western US, reshaping the air we breathe. As their impact grows, so does the urgency for public health strategies and better tools to protect indoor air. That\u2019s why we helped launch the first Clean Air Center in Los Angeles. <\/p>\n\n\n\n
| Wildfires were responsible for:<\/td> | During fire season (July to September)<\/strong><\/td>| Annually<\/strong><\/td><\/tr> | PM2.5<\/strong><\/td> | 52-58%<\/td> | 35-47%<\/td><\/tr> | Carbon monoxide (CO)<\/strong><\/td> | 14-23%<\/td> | 5-12%<\/td><\/tr> | Ozone (O\u2083)<\/strong><\/td> | 10-19%<\/td> | 6-13%<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n | That means, for much of the year, a third to nearly half of all fine particle pollution comes from fires, not cars or factories.<\/strong><\/p>\n\n\n\n On smoke days, the average PM2.5 concentration shot up to 31 \u00b5g\/m\u00b3, compared to just 7 \u00b5g\/m\u00b3 on clean days. That\u2019s more than a fourfold increase, and enough to push many cities into the \u201cunhealthy\u201d AQI zone.<\/p>\n\n\n\n The study also looked at gases released during smoke days. Wildfires don\u2019t emit ozone directly. But they do release volatile organic compounds (VOCs)<\/strong> and NO\u2093<\/strong>, which then react in sunlight to form ozone. So the fires are indirectly boosting ground-level ozone, another lung irritant. PM\u2082.\u2085, or particulate matter smaller than 2.5 micrometers (2,500 nanometers), is a common and harmful component of wildfire smoke. On clean days, the geometric mean diameter (GMD) of airborne particles is about 72 nanometers (nm). During smoky days, that number jumps to 139 nm.<\/p>\n\n\n At first glance, that might seem like an improvement, bigger particles must be less harmful, right? Not quite. Even at 139 nm, these particles are still ultrafine, far smaller than a human hair (which is around 75,000 nm thick).<\/p>\n\n\n\n Both 72 nm and 139 nm particles are small enough to bypass your body\u2019s natural defenses, reach deep into the lungs (the bronchi and alveoli), and potentially enter the bloodstream. So no, the slightly larger size of wildfire smoke particles doesn\u2019t make them any safer. They\u2019re still firmly in the danger zone.<\/p>\n\n\n\n Wildfires are no longer just seasonal hazards, they\u2019re now the dominant source of air pollution in the Western US, reshaping the air we breathe. As their impact grows, so does the urgency for public health strategies and better tools to protect indoor air. That\u2019s why we helped launch the first Clean Air Center in Los Angeles. <\/p>\n\n\n\n |