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Decoupling peroxyacetyl nitrate from ozone in Chinese outflows observed at Gosan Climate Observatory

“…This mean value is lower than those observed in other Asian megacities: Beijing (1.41 ppb in the summer), the Pearl River Delta region (1.32 ppb in the summer), and Seoul (0.8 ppb in the early summer); it is similar to those of suburban areas in China, e.g., Lanzhou (0.76 ppb in the summer), and higher than those of urban and rural sites in Japan (e.g., Tokyo (up to 0.6 ppb in the fall), Rishiri Island (∼ 0.5 ppb in spring)), the western coast of the US (e.g., Sacramento (0.45 ppb in the summer), Mt. Bachelor (0.144 ppb in the spring and early summer)), off the western coast of the US (0.65 ppb in the spring), and over the remote North Pacific (total PAN < 0.3 ppb in spring) (Bertram et al, 2013;Fischer et al, 2011;LaFranchi et al, 2009;Lee et al, 2008;Roberts et al, 2004;Tanimoto et al, 1999Tanimoto et al, , 2002Wang et al, 2010;Zhang et al, 2009Zhang et al, , 2011. Because the PAN lifetime is greatly dependent on temperature, its concentration decreases with increasing distance from the source regions.…”

“…For this reason, PAN is a very useful indicator of photochemical air pollution. As thermal decomposition is a major PAN sink in the troposphere (Beine et al, 1997;Jacob, 2000;Kenley and Hendry, 1982;Talukdar et al, 1995), the lifetime of PAN depends on temperature. For example, the PAN lifetime is ∼ 5 years at −26 • C and 1 h at 20 • C (Fischer et al, 2010;Zhang et al, 2011).…”

UV absorption spectra and self‐reaction rate constants for primary peroxy radicals arising from the chlorine‐initiated oxidation of carbonyl compounds

“…Radicals were generated by photolysis of Cl 2 at wavelengths longer than the Pyrex cutoff, using Cl 2 /(CH 3 ) 3 CC(O)R (with R = CH 3 or C(CH 3 ) 3 )/O 2 /N 2 mixture: 3 , were introduced in the reaction cell by using bubblers maintained at constant temperature (291 K for TMP and 273 K for TMA), and their partial pressures were controlled by Tylan FC 2900 mass flow controllers. Peroxy radicals were formed by adding an excess of oxygen to ensure the stoichiometric and instantaneous conversion of radicals formed by reactions (5) and (6):…”

“…It was assumed that the ( 3 as it was shown for the neopentyl radical [8]. Hence, conversion of Cl atoms into peroxy radicals is complete on a time scale that is essentially instantaneous when compared to that of the observations (Fig.…”

“…Second, they can form stable peroxyacylnitrates (RC(O)O 2 NO 2 ), which are severe irritant compounds in photochemical smog. Moreover, due to their high stability in polluted atmosphere, compared to that of other peroxynitrates, they are efficient reservoirs of NO x in the troposphere and contribute to their transport far away from sources [3]. In air masses with low [NO x ], acylperoxy radicals undergo reactions with HO 2 and other peroxy radicals.…”