section_path: Impact/Air quality and health
section_name: Air quality and health
paragraph_text: Air quality and health
  
  Winds blew wildfire smoke across Los Angeles, leading to several "very unhealthy" air quality index readings of over 200, with the PM2.5 of the Harrison ES station reaching 184.1 μg/m 3, or 36.8 times the annual World Health Organization guideline value. Air quality degraded to 569 μg/m 3 in the region, representing the most hazardous category and necessitating avoidance of all outdoor activity. UCLA Health pulmonologist May-Lin Wilgus expected LA residents to suffer from burning eyes and irritation due to the concentrated smoke, and urged residents with underlying health conditions such as COPD and asthma to avoid all outdoor activity and to close all doors and windows while running air conditioning. Los Angeles City Council president Marqueece Harris-Dawson reported that visibility had fallen below one block in Southern Los Angeles, and urged residents to avoid driving when possible.
  
  Additional monitoring data from the California Air Resources Board (CARB) recorded PM2.5 levels in hazardous ranges at multiple sites across Los Angeles County. The Los Angeles-North Main Street monitoring station registered a one-hour peak of 483.7 μg/m³, while daily averages at several sites, including Compton (51.7 μg/m³), North Hollywood (50.1 μg/m³), and Reseda (47.0 μg/m³), remained well above the U.S. Environmental Protection Agency (EPA) safety threshold of 35 μg/m³. These readings highlight both the acute pollution spikes during the fires and the prolonged air quality deterioration in the days that followed.
  
  The United States Department of Agriculture and the Los Angeles Department of Public Health warned that the wildfires can render some food in the nearby area unsafe to be eaten due to the smoke fumes and other chemicals. Carcinogens are common in smoke from urban fires and pose long-term health risks to those who inhale it, particularly firefighters without respiratory protection.
  
  Environmental Protection Agency air quality data indicated that millions of Los Angeles area residents experienced severe air quality deterioration, with conditions reaching the "Unhealthy" category on EPA scales and escalating to "Hazardous" levels near the fire zones. The combustion of urban structures was estimated to have released numerous harmful substances that are not accounted for in PM2.5 readings, including heavy metals such as lead or zinc. Co-founder and chief meteorologist of Weather Underground Jeff Masters predicted that up to thousands of individuals could die prematurely due to even short-term exposure to the wildfires' smoke. Based on a 2024 study on long-term wildfire smoke exposure in the US, he also predicted that smoke exposure could cause several long-term effects in Californians, including reproductive, cardiovascular, respiratory, renal, endocrine, and neurodevelopmental disorders.
  
  In February, CDC reported that a 110-fold increase in air lead levels during the 2025 LA fires was recorded. The built environment with painted surfaces, pipes, vehicles, plastics, electronic equipment, and buildings combusted, of which a large proportion had been built before 1978.
  
  Winds blew wildfire smoke across Los Angeles, leading to several "very unhealthy" air quality index readings of over 200, with the PM2.5 of the Harrison ES station reaching 184.1 μg/m 3, or 36.8 times the annual World Health Organization guideline value. Air quality degraded to 569 μg/m 3 in the region, representing the most hazardous category and necessitating avoidance of all outdoor activity. UCLA Health pulmonologist May-Lin Wilgus expected LA residents to suffer from burning eyes and irritation due to the concentrated smoke, and urged residents with underlying health conditions such as COPD and asthma to avoid all outdoor activity and to close all doors and windows while running air conditioning. Los Angeles City Council president Marqueece Harris-Dawson reported that visibility had fallen below one block in Southern Los Angeles, and urged residents to avoid driving when possible.
  
  Additional monitoring data from the California Air Resources Board (CARB) recorded PM2.5 levels in hazardous ranges at multiple sites across Los Angeles County. The Los Angeles-North Main Street monitoring station registered a one-hour peak of 483.7 μg/m³, while daily averages at several sites, including Compton (51.7 μg/m³), North Hollywood (50.1 μg/m³), and Reseda (47.0 μg/m³), remained well above the U.S. Environmental Protection Agency (EPA) safety threshold of 35 μg/m³. These readings highlight both the acute pollution spikes during the fires and the prolonged air quality deterioration in the days that followed.
  
  The United States Department of Agriculture and the Los Angeles Department of Public Health warned that the wildfires can render some food in the nearby area unsafe to be eaten due to the smoke fumes and other chemicals. Carcinogens are common in smoke from urban fires and pose long-term health risks to those who inhale it, particularly firefighters without respiratory protection.
  
  Environmental Protection Agency air quality data indicated that millions of Los Angeles area residents experienced severe air quality deterioration, with conditions reaching the "Unhealthy" category on EPA scales and escalating to "Hazardous" levels near the fire zones. The combustion of urban structures was estimated to have released numerous harmful substances that are not accounted for in PM2.5 readings, including heavy metals such as lead or zinc. Co-founder and chief meteorologist of Weather Underground Jeff Masters predicted that up to thousands of individuals could die prematurely due to even short-term exposure to the wildfires' smoke. Based on a 2024 study on long-term wildfire smoke exposure in the US, he also predicted that smoke exposure could cause several long-term effects in Californians, including reproductive, cardiovascular, respiratory, renal, endocrine, and neurodevelopmental disorders.
  
  In February, CDC reported that a 110-fold increase in air lead levels during the 2025 LA fires was recorded. The built environment with painted surfaces, pipes, vehicles, plastics, electronic equipment, and buildings combusted, of which a large proportion had been built before 1978.