Satellite data from across California’s landscapes reveal an increase in nitrogen dioxide levels in remote forest areas, and wildfire and soil emissions are likely the reasons why, according to a paper from University of California, Davis, published today in the journal Environmental Research Letters. Nitrogen dioxide is short-lived in the atmosphere but plays a central role in the formation of the pollutants ozone and particulate matter, which can lead to respiratory issues and asthma in humans, as well as harm plants and crop yields. The researchers looked at summertime surface and satellite concentrations of nitrogen dioxide between 2009 and 2020 and found that levels decreased by 2-4.5% per year in urban areas across California, while rural concentrations remained relatively constant, and remote forests experienced an increase of roughly 4.2% per year. …The findings could help inform future policy decisions as regulators seek additional decreases of the pollutant.