Researchers recently provided new insights into the atmosphere’s “self-cleaning” ability.
This self-cleaning process is vital for removing gaseous pollutants and regulating greenhouse gases like methane in the atmosphere.
Scientists were already aware of the atmosphere’s “self-cleaning” ability, but recent research from the University of York has revealed a new process that enhances the ability of the marine atmosphere to self-cleanse.
Using a combination of aircraft and ground-based observations, it was possible for the researchers to verify the high prevalence of nitrous oxide (HONO) in the remote Atlantic troposphere formed by “renoxification,” which occurs when photolysis of aerosol nitrate returns NOx and HONO to the marine atmosphere.
According to the researchers, the observations, which were published in the journal Sciences Advances, could have a significant impact on atmospheric chemistry and help to resolve widespread uncertainty about the significance of renoxification.
Using financial support from the Natural Environmental Research Council (NERC), researchers from the Wolfson Atmospheric Chemistry Laboratories (WACL) directed comprehensive aircraft and ground-based observations in and around Cape Verde in August 2019 and February 2020.
Importantly, the observations showed that the efficiency of renoxification increased with relative humidity and decreased with the concentration of nitrate. This observation reconciled the very large discrepancies in the rates of renoxification found across multiple laboratory and field studies.
Lucy Carpenter, Study Lead Author and Professor, University of York
Lucy Carpenter explains, “It was also consistent with renoxification occurring on the surface of aerosols, rather than within their bulk, a new and exciting finding with implications for how this fundamental process is controlled and parameterized in models.”
The recycling of nitrogen oxides on nitrate aerosol could have notable, increasing, and undiscovered consequences for the trends and distributions of atmospheric oxidants like tropospheric ozone, a significant greenhouse gas.