Wildfires and farm fertilizer use are fueling a surge in ozone pollution, with soil and wildfire emissions of nitrogen-containing ozone precursors contributing as much to urban areas in the US Southwest as traditional anthropogenic sources.
The Shifting Chemistry of Our Atmosphere: How Wildfires and Farm Fertilizer are Fueling Ozone Pollution
Ground-level ozone pollution has long been a concern for public health, but recent research suggests that wildfires and farm fertilizer use may be playing a significant role in its increase. Analyzing satellite data and ground-level observations, atmospheric chemist Ian Faloona and his colleagues have found that soil and wildfire emissions of nitrogen-containing ozone precursors, collectively referred to as ‘NOx,’ are increasingly raising ozone levels in major air basins in the southwestern United States.
The Rise of Unregulated Ozone Precursors
While regulations have limited NOx production by human-made sources, particularly in urban areas, satellite data since 2015 has shown rising NOx levels in remote areas of California. Faloona found patterns linked with an alarming rise in recent wildfire activity and increasing soil emissions due to a warming climate and rising fertilizer use. These findings come as wildfires have ravaged areas coast-to-coast in the United States, from January’s devastating fires in Los Angeles to more recent conflagrations in South Carolina and Long Island, N.Y.
The Impact of Wildfire Smoke
Previous research has shown how wildfire smoke wafting over cities can jump-start ozone production. Dan Jaffe, a climatologist at the University of Washington in Bothell, Wash., recently showed that the number of days that exceed national air quality ozone thresholds doubles during high wildfire years. However, it was unclear how much wildfire smoke contributed to the problem.
Wildfire smoke is a mixture of gases and particles emitted by wildfires, including particulate matter (PM), 'carbon monoxide' , and volatile organic compounds.
These pollutants can travel long distances, affecting air quality in nearby communities.
According to the Environmental Protection Agency (EPA), wildfire smoke contains over 100 known toxic chemicals.
Exposure to prolonged periods of poor air quality due to wildfire smoke has been linked to respiratory issues, cardiovascular problems, and increased risk of 'cancer' .
Faloona developed a method to derive how much of the ozone came from various sources and found a fundamental shift. A steady decrease over the past several decades has now stalled. The vast majority of ozone — 64 to 70 ppb — still wafts in from the Pacific Ocean from sources beyond U.S. borders, as it has since the 1990s. Meanwhile, now-regulated automobile and industrial sources, which once accounted for as much as 15 to 20 ppb in mid-sized cities, now contribute under 6 ppb in most urban areas (excluding megapolises like Los Angeles).
Wildfire and soil impacts boost ozone by another 1 to 7 ppb, he found, or up to 50 percent of the excess ozone. In a follow-up study focused on one air basin free of wildfire impacts, he found that some 2 ppb of NOx in the air came from agricultural fertilizers.
The Consequences of Unregulated Ozone Precursors
Those numbers might not sound like much. But when it comes to trying to stay below 70 ppb, every bit counts. What emerges is that unregulated sources of ozone precursors from wildfires and agricultural soils are presently contributing as much to most urban areas in the U.S. Southwest as are traditional anthropogenic sources.
However, some of this data aren’t always figured into efforts to combat ozone. For instance, for states calculating ozone compliance, the EPA offers a mechanism to exclude data that came from exceptional events — like wildfires. Demonstrating that a day was influenced by smoke is so complicated that states rarely invoke the rule. ‘If you’re holding the wrong person accountable for pollution they didn’t cause, our system breaks down,’ Jaffe says.
A New Air Quality Photochemical Regime
Faloona’s findings come at a critical time and highlight the need to reassess our approach to air quality regulations. As we continue to face the challenges of climate change, it is essential that we support climate journalism and ensure that our response to climate change is informed by science.
Air quality regulations aim to mitigate the adverse effects of air pollution on human health and the environment.
These regulations typically set standards for emissions from industrial sources, vehicles, and other polluters.
Key components include monitoring and reporting requirements, emission limits, and enforcement mechanisms.
In the United States, the Clean Air Act is a primary example of federal legislation governing air quality.
The act sets national ambient air quality standards (NAAQS) for six common pollutants: particulate matter, ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide, and lead.
Supporting science literacy and understanding can have a significant impact on our ability to address environmental issues like ozone pollution. By staying informed and engaged, we can work towards a healthier environment for ourselves and future generations.
Science literacy refers to the ability to understand and interpret scientific information.
It involves critical thinking, analytical skills, and the capacity to evaluate evidence-based data.
In today's world, science literacy is crucial for making informed decisions about health, technology, and environmental issues.
According to a survey by the National Science Foundation, 70% of adults in the US lack basic understanding of science concepts.
Improving 'science literacy' can lead to better decision-making, increased innovation, and improved public health outcomes.
- sciencenews.org | Wildfires and farm fertilizer use are fueling ozone pollution
