“We found that levels of nitrous acid in wildfire plumes around the world are now two to four times higher.
Nitrous acid in forest fire smoke acceleratesthe formation of an oxidizing agent, hydroxyl radical or OH. The group estimated that nitrous acid was responsible for 60% of the formation of OH in plumes of smoke worldwide - by far the main precursor of the hydroxyl radical in fresh plumes of fire. Thus, OH can decompose greenhouse gases as well as accelerate the chemical production of ozone pollution - up to 7 parts per billion in some places. This is enough for ozone levels to exceed US and European regulatory levels.
"Size of fire and burning conditions in the real worldshow a higher content of nitrous acid than can currently be explained on the basis of laboratory data, and this added nitrous acid accelerates the chemical process to produce ozone, ”explains Volkamer.
Nitrous acid, although present in a largequantity after forest fires, quickly decomposes in the sun, and therefore it is extremely difficult to study. The CU Boulder team worked with European counterparts to combine two datasets:
- Global measurements with the TROPOMI satellite instrument, which observed nitrous acid in wildfire plumes around the world;
- Special instruments used on airplanes during the study of fires in 2018. Pacific Northwest during the BB-FLUX campaign.
“Simultaneous measurements taken in differenttime and space scales helped us understand and use the first global measurements of nitrous acid by our Belgian colleagues, ”said Volkamer. With the new data, Volkamer and his colleagues, including Nicholas Theiss, lead author of the study at BIRA, were able to scrutinize satellite data on large numbers of wildfires in all major ecosystems across the planet to estimate nitrous acid emissions.
"Emissions of nitrous acid compared to othersozone-producing gases vary by ecosystem, with the lowest in savannas and grasslands and highest in extratropical evergreen forests, ”explains Kyle Zarzana, a chemical scientist at CU Boulder, who led the deployment of aircraft and co-author of a new article.
“Smoke from forest fires contains manycontaminants and aerosols that negatively affect visibility and public health over long distances, as we see in the wildfires raging in the western United States, affecting air quality and the east coast. Our results show that this smoke is a highly reactive chemical and helps us track better as photochemistry rapidly changes downwind emissions, ”the scientists conclude.
Read also
In the era of ecosystems: how IT giants are turning into interfaces of our everyday life
The Doomsday glacier turned out to be more dangerous than scientists thought. We tell the main thing
GitHub has replaced the term "master" with a neutral equivalent