Black Carbon

Climate
Written By Alysha Rashid

The gains we’ve made in reducing airborne black carbon (soot) are fading, as wildfires have increased pollution levels in recent years.

Black carbon pollution levels across 30 sites in the U.S.

Annual concentration in micrograms per cubic meter

Source: Dr. Charles Stanier, Dr. Gregory Carmichael, and Dr. Peter S. Thorne analysis of data from  IMPROVE/Colorado State University. Notes: Data is averaged across 30 primarily rural locations with long-term monitoring. Commonly known as soot, black carbon is emitted by diesel-fueled vehicles, industrial processes, residential fireplaces and woodstoves. Wildfires are its largest natural source.

Black carbon, or soot, is a type of solid particle that absorbs light and releases heat energy into the air, contributing to global warming and air pollution.1,2 EPA regulations helped to steadily decrease the presence of black carbon released from sources such as automobiles, trucks, and factories. However, rising global temperatures and human activity have led to more frequent wildfires that release that same particle — reversing over 20 years of U.S. progress.[3] Black carbon is a component of fine inhalable particulate matter, known as PM2.5, which is 30 times smaller than the diameter of a single strand of hair. When PM2.5 is ingested into the body, usually through the lungs, it can wreak havoc on the cardiovascular and respiratory systems.[4],[5] Studies show that both short and long term exposure to black carbon can cause increased emergency room visits, asthma attacks, heart attacks, strokes, and even premature death.[3],[6],[7]

The Clean Air Act has been a primary driver in the reduction of black carbon across the U.S., but more steps must be taken to curb the rising trend, including switching to zero-emission vehicles, investing in wildfire prevention and management, expanding investment in public transit, continued reduction of coal and fossil-fuel reliance, and increasing reliance on renewable energy (Greenhouse Gas Emissions, Public Transportation).[8],[9] Utilizing air quality tools like AirNow.gov and the Air Quality Flag Program can also help communities to alert vulnerable residents so they can reduce their exposure and minimize harm.[10],[11]

  1. Atmospheric black carbon concentrations. (2024). Ca.gov; California Office of Environmental Health Hazard Assessment. https://oehha.ca.gov/climate-change/epic-2022/climate-change-drivers/atmospheric-black-carbon-concentrations

  2. Black Carbon and Its Effects on Climate | Chapter 2. (2012). Environmental Protection Agency. https://www3.epa.gov/airquality/blackcarbon/2012report/Chapter2.pdf

  3. Higuera, P. E., Cook, M. C., Balch, J. K., E. Natasha Stavros, Mahood, A. L., & Ann, L. (2023). Shifting social-ecological fire regimes explain increasing structure loss from Western wildfires. PNAS Nexus, 2(3). https://doi.org/10.1093/pnasnexus/pgad005

  4. CDC. (2020, December 21). Climate Change and Public Health - Health Effects - Air Pollution. Centers for Disease Control and Prevention. https://www.cdc.gov/climateandhealth/effects/air_pollution.htm

  5. Air Pollution: Current and Future Challenges. (n.d.). Www.epa.gov. https://www.epa.gov/clean-air-act-overview/air-pollution-current-and-future-challenges#toxic

  6. Wei, J., Wang, J., Li, Z., Kondragunta, S., Anenberg, S., Wang, Y., Zhang, H., Diner, D., Hand, J., Lyapustin, A., Kahn, R., Colarco, P., da Silva, A., & Ichoku, C. (2023, December). Long-term mortality burden trends attributed to black carbon and PM2·5 from wildfire emissions across the continental USA from 2000 to 2020: a deep learning modelling study. The Lancet. https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(23)00235-8/fulltext

  7. Black Carbon and Its Effects on Climate | Chapter 3. (2012). Environmental Protection Agency. https://www3.epa.gov/airquality/blackcarbon/2012report/Chapter3.pdf

  8. CLIMATE CHANGE AND SOCIAL VULNERABILITY IN THE UNITED STATES A Focus on Six Impacts. (2021). U.S. Environmental Protection Agency. https://www.epa.gov/system/files/documents/2021-09/climate-vulnerability_september-2021_508.pdf

  9. What to Do to Fight Climate Change. (n.d.). Www.lung.org; American Lung Association. https://www.lung.org/clean-air/climate-change/fight-climate-change

  10. CDC. (n.d.). CLIMATE CHANGE DECREASES THE QUALITY OF THE AIR WE BREATHE. U.S. Department of Health and Human Services. https://www.cdc.gov/climateandhealth/pubs/AIR-QUALITY-Final_508.pdf

  11. AirNow. (n.d.). AirNow. Airnow.gov. https://www.airnow.gov/

  12. Air Quality Flag Program Main Page | AirNow.gov. (n.d.). Www.airnow.gov. https://www.airnow.gov/air-quality-flag-program

Alysha Rashid
Previous

Heat-related Deaths
Next

Greenhouse Gas Emissions