PM1 Pollution in America: Health Risks & Map
- Air pollution contributes to approximately 50,000 deaths annually in the U.S., but the impact varies among pollutants.
- The study, published in The Lancet planetary Health, provides critical data for understanding and regulating this pollutant.
- Randall Martin, professor at the McKelvey School of Engineering, saeid the measurements offer a starting point for regulators to target pollutants effectively.
Uncover critical insights into PM1 pollution in America.A new 25-year study quantifies PM1 levels,revealing air quality trends and potential health risks. Unlike PM2.5, these even smaller particles may pose a greater threat. Researchers from Washington University in St. Louis have created a thorough dataset, providing a starting point for regulatory action and highlighting teh impact of wildfires and other sources on PM1 pollution. While regulations initially curbed PM1, progress has slowed. News Directory 3 keeps you informed on ever-evolving environmental concerns. Discover what’s next in air quality research and future regulations.
Study Quantifies PM 1 Pollution, Reveals Air Quality Trends
Updated june 16, 2025
Air pollution contributes to approximately 50,000 deaths annually in the U.S., but the impact varies among pollutants. Scientists have long monitored PM 2.5 pollution, particulate matter smaller than 2.5 microns. However, less is known about PM 1 pollution, also known as submicron particulate matter, wich is less than 1 micron. These smaller particles may have more severe health effects.
Researchers at Washington University in St. Louis have now quantified PM 1 pollution across the U.S. over the past 25 years. The study, published in The Lancet planetary Health, provides critical data for understanding and regulating this pollutant.
Randall Martin, professor at the McKelvey School of Engineering, saeid the measurements offer a starting point for regulators to target pollutants effectively. He added that the study leverages WashUS expertise in satellite remote sensing and atmospheric aerosol modeling.
Chi Li, research assistant professor, led the study. li said the estimates will enable further research into the health and environmental effects of submicron particles.
These tiny particles typically originate from direct emissions, such as diesel engine exhaust and wildfire smoke. PM 1 pollution can also form secondarily from sulfur dioxide or nitrogen oxides released during fuel combustion and coal burning.
Smaller particles are thought to be more harmful because they bypass the body’s defenses more easily. Submicron particles are at least six times smaller than blood cells.
Li noted that larger particles are frequently enough dominated by less modifiable components like mineral dust. Researchers calculated submicron estimates using known ratios of PM 2.5 components, including sulfate, nitrate, and mineral dust.
Li said combining these components allows for calculating the total PM 1 concentration across the country.
the research paves the way for analyzing the sources, distribution, and impacts of different particle types on the habitat and human health.
“When EPA first promulgated a fine PM air quality standard in 1997, there was considerable discussion about regulating PM 1 or PM2.5,” said Jay Turner, professor at the James McKelvey Professor of Engineering Education. “For numerous reasons, including but not limited to the lack of health impacts studies for PM 1 compared to studies for PM 2.5, the latter was chosen. This study provides a comprehensive, nationwide dataset to examine PM1 impacts on health.”
Future research will involve epidemiologists assessing the link between PM 1 pollution and health outcomes.
The data shows that pollution regulations have been effective. Average PM 1 levels in the contiguous U.S. decreased considerably from 1998 to 2022 due to regulations like the Clean Air Act. However, progress has slowed since 2010 due to increased wildfire activity. Future controls must address emerging,non-fossil fuel sources.
Martin said this dataset provides unprecedented details about an important pollutant with limited existing measurements in the U.S.
What’s next
The study’s findings will be used to collaborate with epidemiologists to assess the association of PM 1 with health outcomes, possibly leading to new air quality regulations.