The devastating effects of California’s wildfires during this winter not only present a visible destruction but are also contributing to an increase in ground-level ozone pollution. Researchers have discovered that soil and wildfire emissions of nitrogen-containing ozone precursors, known as NOx, are now rivaling human-made sources of these pollutants, such as cars and factories, in areas across the southwestern United States. This increase in ozone levels poses a significant shift in the atmosphere’s chemistry, potentially making air pollution standards unachievable.
Ian Faloona, an atmospheric chemist at the University of California, Davis, has analyzed satellite data and ground-level observations to identify the sources contributing to ozone in major air basins in the southwestern United States. The study found that NOx emissions from soil and wildfires are on the rise, and in some cases, their levels are comparable to those from traditional human-made sources. Faloona presented these findings at the American Meteorology Society’s annual meeting in New Orleans and highlighted how these natural sources of pollutants are affecting air quality.
The standard for ozone levels has been continuously lowered over the past few decades, with the most recent adjustment in 2015 setting it at 70 parts per billion over an eight-hour average. However, the challenges arise as projections for future emissions do not accurately account for significant sources like wildfires and agricultural emissions, such as rising fertilizer use. Faloona points out that despite efforts to reduce NOx emissions from human-made sources, such as cars and industries, satellite data since 2015 indicates an increase in remote areas of California due to wildfires and soil emissions.
The impact of wildfires on ozone production has been previously acknowledged, especially with wildfire smoke contributing to elevated levels of ozone. Faloona’s study elucidates how much of the ozone is attributed to wildfires and agricultural practices. The findings are crucial as wildfires have ravaged various parts of the United States, highlighting the urgent need to address these sources of pollution to better regulate air quality standards.
Recent data from California reveals that while ozone levels have decreased over the decades, they are still above the EPA standard for ambient air quality. A key takeaway from Faloona’s research is the significant contribution of wildfires and agricultural activities to ozone pollution, with up to 50% of excess ozone attributed to these sources in some regions. Understanding these contributions is vital for formulating effective strategies to combat ozone pollution and protect public health. Efforts must be made to consider these natural sources of pollution in regulations and standards to ensure cleaner air for all.
