Observation of gas-phase peroxynitrous and peroxynitric acid during the photolysis of nitrate in acidified frozen solutions

• Published in: Chemical physics letters 2011-08, Vol.511 (4), p.187-192
• Main Authors: Abida, Otman, Mielke, Levi H., Osthoff, Hans D.
• Format: Article
• Language: English
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2011.06.055

[Display omitted] ► Photolysis of nitrate in frozen solutions produces volatile nitrogen oxides. ► Under neutral or basic conditions, the dominant species emitted is NO 2. ► Under acidic conditions, the nitrogen oxides released are mainly NO z species. ► Peroxynitrous and peroxynitric acid were observed by chemical ionization mass spectrometry. ► HOONO may be an important but overlooked intermediate in the troposphere. The photolysis of nitrate embedded in ice and snow can be a significant source of volatile nitrogen oxides affecting the composition of the planetary boundary layer. In this work, we examined the nitrogen oxides evolved from irradiated frozen solutions containing nitrate. Products were monitored by cavity ring-down spectroscopy (CRDS), NO-O 3 chemiluminescence (CL), and chemical ionization mass spectrometry (CIMS). Under acidic conditions, the nitrogen oxides volatilized were mainly in the form of NO z, i.e., nitrous (HONO), nitric (HONO 2), peroxynitrous (HOONO), and peroxynitric acid (HO 2NO 2). Identification of acidic nitrogen oxides by CIMS and possible HOONO, HONO 2 and HO 2NO 2 formation pathways are discussed.