It is believed that both forest fires and soil emissions could be the main causes of Rising nitrogen dioxide levels in remote forested areas of California speak for themselves satellite data from orNO Article from the University of California, Davis, published in the journal today environmental research letters.
Nitrogen dioxide is a gas that does not stay in the atmosphere for long, but has a significant impact on the formation of pollutants such as ozone and particulate matter. These can cause respiratory problems and asthma in humans, damage plants and have a negative impact on crop yields.
Researchers conducted a study examining summer nitrogen dioxide concentrations in California between 2009 and 2020. Using data collected both on the surface and via satellite, they found that levels in urban areas of the state were dropping an average of 2-4.5% each year. while the rural concentration remained relatively constant and remote forests saw an increase of about 4.2% per year.
Nitrogen dioxide levels and their relationship to forest fires
“Forest areas show a constant and rapid increase in summersaid biomicrometeorologist Ian Faloona, lead author of the paper and professor in the Department of Earth, Air and Water Resources. “The trend is alarming“.
In the study, the scientists examined the nitrogen dioxide content at the surface. To do this, they analyzed both government-collected data and data obtained via NASA’s Aura satellite. They classified the areas with nitrogen dioxide deposits based on surface temperature and soil moisture. A database of California fire incidents was used to help classify the areas. This database provided valuable information for categorizing land into one of five categories: urban, forested, agricultural, bushy, or barren (with little vegetation).
New sources to consider
Controls on internal combustion engines and other fossil fuel emitters have reduced nitrogen dioxide levels in urban areas where most air pollution monitors are located. Continuous satellite data completed the picture in less monitored regions, revealing that the effect is not reflected in rural areas and remote forests. There, wildfires and emissions from soils, particularly agricultural soils with fertilizer use, correlate with elevated levels of nitrogen dioxide, Faloona said.
The discoveries may be useful in influencing future policy decisions, particularly as regulators seek to further reduce the presence of pollutants. As current emissions management strategies continue to reduce fossil fuel emissions, regulators must begin to address other sources that have historically been underestimated compared to traditional combustion sources. These will play an increasingly important role in reducing emissions. future air quality policy.
“Soils and especially forest fires are actually becoming the rudder of our air pollution.said Falcon. “We must work hard to reduce the impact of wildfires and better understand our emissions from agricultural soils“.
Additional research required about forest fires
In areas with high fertilizer use, there is a risk of nitrogen dioxide emissions. This is because microorganisms compete with crops for nitrogen, resulting in the production of gaseous nitrogen compounds. Although wildfires and soil have been shown to contribute to increases in nitrogen dioxide levels in the environment, it is important to note that more research is needed to fully understand its exact role.
This additional research will help us gain clarity on how these specific factors are involved in this surge and how we can effectively counteract it.
“Our results point to opportunities for different policy packages and technologies to help reduce nitrogen dioxide concentrations in rural and economically disadvantaged areas of California, but require a concerted effort to better understand the precise environmental dependencies of soil and fire emissions. forestry‘ the authors wrote.
The research was done in collaboration with Yurun Wang, who currently works in the Department of Land, Air and Water Resources at Hong Kong Polytechnic University, and Professor Benjamin Houlton, formerly at UC Davis and now at Cornell University.
The research was funded by the National Institute of Food and Agriculture, part of the US Department of Agriculture.
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