Extensive field evidence for the release of HONO from the photolysis of nitrate aerosols.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36652523.
- Also identified by DOI 10.1126/sciadv.add6266 and PMC identifier 9848427.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Particulate nitrate ([Formula: see text]) has long been considered a permanent sink for NO<i><sub>x</sub></i> (NO and NO<sub>2</sub>), removing a gaseous pollutant that is central to air quality and that influences the global self-cleansing capacity of the atmosphere. Evidence is emerging that photolysis of [Formula: see text] can recycle HONO and NO<i><sub>x</sub></i> back to the gas phase with potentially important implications for tropospheric ozone and OH budgets; however, there are substantial discrepancies in "renoxification" photolysis rate constants. Using aircraft and ground-based HONO observations in the remote Atlantic troposphere, we show evidence for renoxification occurring on mixed marine aerosols with an efficiency that increases with relative humidity and decreases with the concentration of [Formula: see text], thus largely reconciling the very large discrepancies in renoxification photolysis rate constants found across multiple laboratory and field studies. Active release of HONO from aerosol has important implications for atmospheric oxidants such as OH and O<sub>3</sub> in both polluted and clean environments.