NO at low concentration can enhance the formation of highly oxygenated biogenic molecules in the atmosphere
Wei Nie, Chao Yan, Liwen Yang, Pontus Roldin, Yuliang Liu, Alexander L. Vogel, Ugo Molteni, Dominik Stolzenburg, Henning Finkenzeller, Antonio Amorim, Federico Bianchi , Joachim Curtius, LubnaDada, Danielle C. Draper, Jonathan Duplissy, Armin Hansel, Xu-ChengHe, Victoria Hofbauer, Tuija Jokinen, Changhyuk Kim, Katrianne Lehtipalo, Leonid Nichman, Roy L. Mauldin, Vladimir Makhmutov, Bernhard Mentler, Andrea Mizelli-Ojdanic, Tuukka Petäjä, Lauriane L. J. Quéléver, Simon Schallhart, Mario Simon, Christian Tauber, António Tomé, Rainer Volkamer, Andrea C. Wagner, RobertWagner,MingyiWang, PenglinYe,Haiyan Li,WeiHuang, Ximeng Qi, Sijia Lou, Tengyu Liu, Xuguang Chi, Josef Dommen, Urs Baltensperger, Imad El Haddad, Jasper Kirkby, Douglas Worsnop, Markku Kulmala, Neil M. Donahue, Mikael Ehn & Aijun Ding
Nature Communications
Nat. Commun., 14, 3347 (2023)
Publication Date: June 8, 2023
Abstract.
The interaction between nitrogen monoxide (NO) and organic peroxy radicals (RO2) greatly impacts the formation of highly oxygenated organic molecules (HOM), the key precursors of secondary organic aerosols. It has been thought that HOM production can be significantly suppressed by NO even at low concentrations. Here, we perform dedicated experiments focusing on HOM formation from monoterpenes at low NO concentrations (0 – 82 pptv). We demonstrate that such low NO can enhance HOM production by modulating the RO2 loss and favoring the formation of alkoxy radicals that can continue to autoxidize through isomerization. These insights suggest that HOM yields from typical boreal forest emissions can vary between 2.5%-6.5%, and HOM formation will not be completely inhibited even at high NO concentrations. Our findings challenge the notion that NO monotonically reduces HOM yields by extending the knowledge of RO2-NO interactions to the low-NO regime. This represents a major advance towards an accurate assessment of HOM budgets, especially in low-NO environments, which prevails in the pre-industrial atmosphere, pristine areas, and the upper boundary layer.