A new study published in Environmental environment Researchers at the University of North Carolina at Chapel Hill analyzed spatial and temporal trends in fine particulate matter (PM2.5) across the continental United States to determine regulatory actions by federal, state, and local authorities to curb air pollution. Progress can be tracked. The team found that the annual average concentration for PM2.5 was significantly reduced, but its chemical composition had changed during the study period from 2006 to 2020. Their analysis suggests that there may be more targeted strategies to reduce pollution specific to different regions of the United States. Effective in further reducing total air pollution and PM2.5 related adverse health effects. PM2.5, an air pollutant, is a mixture of several chemical species and includes fine particles less than 2.5 microns in size. PM2.5 is associated with many adverse human health effects, including premature death. It can also reduce visibility by creating haze in the air.

“The results of this study are particularly relevant to the EPA’s revision of the health-based standard for PM2.5 from 12 µg/m3 to 9 µg/m3,” said Saravanan Arunachalam, senior author of the study. and Deputy Director of the UNC Institute for the Environment. “Monitoring states that are exceeding the new standard for PM2.5 will try to understand the chemical components of PM2.5, and how they have changed over time, and that in the future. Addressing potential non-attainment will be key to creating emission reduction policies. designation.”

Using data from the US EPA Air Quality System (AQS), the research team examined trends in the 48 contiguous US states. Chemicals found in PM2.5 in the US include sulfate, ammonium, nitrate, organic carbon, elemental carbon and other trace elements, which come from a variety of man-made and natural sources.

The greatest improvements in air quality over the 15-year period analyzed were seen in areas with the worst air quality. For example, the Ohio Valley and southeastern states have seen the greatest improvement due to regulations on emissions sources such as coal-burning power plants and industry. Emissions of sulfur dioxide, a byproduct of fossil fuel combustion, fell by 91.5 percent from power plants during the study period. Most of the sulfur dioxide emissions in the study came from the Ohio Valley and the southeastern U.S. An increase in poor air quality along the West Coast in 2020 was likely due to widespread wildfires.

Although sulfate and ammonium levels have declined across the U.S., the researchers suggest reducing other sources of carbon in the atmosphere to further improve air quality, increasing carbon in total PM2.5. Given the contribution, high pollution days have decreased in recent years, but primary organic carbon peaked during the winter months due to reduced rates of secondary organic aerosol formation at low temperatures.

These regional differences, the researchers point out, indicate that regionally targeted approaches to reducing air pollution will further improve the nation’s air quality and health care for air pollution-related health problems. will reduce costs and save more lives.

“Different chemical components of PM2.5 are associated with different emission sources, thus the development of future emission control strategies to reduce PM2.5 concentrations depends on spatiotemporal trends in the chemical composition of PM2.5.” “Must be based on comprehensive analysis and deep understanding,” said Bin Cheng, co-author and research associate at the institute, of the relationship between emissions and changes in ambient concentrations.

“The findings of this study will also contribute to future epidemiological studies to identify specific PM2.5 components that affect human health more than others,” Arunachalam added.