In lab studies of wildfire, nitrous acid seems like a minor actor, often underrepresented in atmospheric models. But in the real-world atmosphere, during wildfires, the chemical plays a leading role—spiking to levels significantly higher than scientists expected, driving increased ozone pollution and harming air quality, according to a new study led by the University of Colorado Boulder and the Belgian Institute for Space Aeronomy.
“We found nitrous acid levels in wildfire plumes worldwide are two to four times higher than expected,” said Rainer Volkamer, CIRES Fellow, professor of chemistry at CU Boulder and co-lead author on the Nature Geoscience study. “The chemical can ultimately drive the formation of lung- and crop-damaging ozone pollution downwind of fires.”
Nitrous acid in wildfire smoke is accelerating the formation of an oxidant, the hydroxyl radical or OH. Unexpectedly, nitrous acid was responsible for around 60 percent of OH