Parahalogenated phenols accelerate the photochemical release of nitrogen oxides from frozen solutions containing nitrate.
The photolysis of nitrate anion (NO(3)(-)) contained in surface ice and snow can be a regionally significant source of gas-phase nitrogen oxides and affect the composition of the planetary boundary layer. In this study, the photochemical release of nitrogen oxides from frozen solutions containing NO(3)(-) in the presence of organic compounds was investigated. Gas-phase nitrogen oxides were quantified primarily by NO-O(3) chemiluminescence detection of NO and NO(y) (=NO + NO(2) + HONO + HNO(3) + ∑PAN + ∑AN ...) and cavity ring-down spectroscopy of NO(2) and total alkyl nitrates (∑AN). The photochemical production of gas-phase NO(y) was suppressed by the presence of formate, methanesulfonate, toluene, or phenol. In contrast, para-halogenated phenols (in the order of Cl > Br > F) promoted the conversion of NO(3)(-) to gas-phase NO(y), rationalized by acidification of the ice surface.
Department of Chemistry, University of Calgary, 2500 University Drive Northwest, Calgary, Alberta T2N 1N4, Canada.
Otman
O
Abida
Hans D
HD
Osthoff
D007053:Ice; D009566:Nitrates / Q000737:chemistry*; D009589:Nitrogen Oxides / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*; D010782:Photolysis; D012996:Solutions; D013499:Surface Properties
D007053:Ice; D009566:Nitrates; D009589:Nitrogen Oxides; D010636:Phenols; D012996:Solutions