Estimating N<sub>2</sub>O<sub>5</sub> uptake coefficients using ambient measurements of NO<sub>3</sub>, N<sub>2</sub>O<sub>5</sub>, ClNO<sub>2</sub> and particle-phase nitrate

Abstract

Abstract. We present an estimation of the uptake coefficient (γ ) and yield of nitryl chloride (ClNO 2 ) (f ) for the heterogeneous processing of dinitrogen pentoxide (N 2 O 5 ) using simultaneous measurements of particle and trace gas composition at a semi-rural, non-coastal, mountain site in the summer of 2011. The yield of ClNO 2 varied between (0.035 ± 0.027) and (1.38 ± 0.60) with a campaign average of (0.49 ± 0.35). The large variability in f reflects the highly variable chloride content of particles at the site. Uptake coefficients were also highly variable with minimum, maximum and average γ values of 0.004, 0.11 and 0.028 ± 0.029, respectively, with no significant correlation with particle composition, but a weak dependence on relative humidity. The uptake coefficients obtained are compared to existing parameterizations based on laboratory datasets and with other values obtained by analysis of field data.

ClNO2 Yields From Aircraft Measurements During the 2015 WINTER Campaign and Critical Evaluation of the Current Parameterization

“…In the first section we discuss trends in this difference with measured aerosol components, particularly aerosol water. The last two sections assess two possible mechanistic sources of ϕ(ClNO 2 ) suppression that have been discussed previously in field (Mielke et al, 2013;Phillips et al, 2016;Tham et al, 2018;Z. Wang, Wang, Tham, et al, 2017) and laboratory-based (e.g., Roberts et al, 2008;Ryder et al, 2015) studies of ClNO 2 yield.…”

“…The WINTER distribution and median appear similar to those reported from both continental and coastal locations across North America (Mielke et al, 2011(Mielke et al, , 2013(Mielke et al, , 2016Osthoff et al, 2008;Riedel et al, 2013;Thornton et al, 2010;Wagner et al, 2012Wagner et al, , 2013; Table S2). The reported average values in Europe (Phillips et al, 2016) and polluted regions in China X. Wang, Wang, Xue, et al, 2017;Z.…”

“…Ambient ClNO 2 was first observed off the coast of Texas in 2006 . It has since been measured from ship-, ground-, and aircraft-based platforms in both continental and coastal/marine environments throughout North America (Edwards et al, 2013;Faxon et al, 2015;Kercher et al, 2009;Kim et al, 2014;Mielke et al, 2011Mielke et al, , 2016Osthoff et al, 2008;Riedel et al, 2012Riedel et al, , 2013Thornton et al, 2010;Wild et al, 2016;Young et al, 2012), Europe and the United Kingdom (Bannan et al, 2015(Bannan et al, , 2017Phillips et al, 2012Phillips et al, , 2016Reyes-Villegas et al, 2018), and Asia (Liu et al, 2017;Tham et al, 2018Tham et al, , 2016Tham et al, , 2014X. Wang, Wang, Xue, et al, 2017;T.…”

“…Relatively few studies, and none from aircraft, have reported field-derived ClNO 2 yields (ϕ(ClNO 2 )), which require simultaneous observations of ClNO 2 and additional measurements such as N 2 O 5 and/or total (particle + gas-phase) nitrate. Existing ground-based determinations of ϕ(ClNO 2 ) have shown no strong seasonal or geographical dependences, and have values that vary within the entire possible range of 0 to 1 (Mielke et al, 2016;Osthoff et al, 2008;Phillips et al, 2016;Riedel et al, 2013;Tham et al, 2016Tham et al, , 2018Thornton et al, 2010;Wagner et al, 2013Wagner et al, , 2012X. Wang, Wang, Xue, et al, 2017;Young et al, 2013;Yun et al, 2018).…”

Introductory lecture: atmospheric chemistry in the Anthropocene

“…23). [582][583][584] This has usually been attributed to the reaction of N 2 O 5 with particulate chloride, with the source of the latter possibly being uptake of HCl from the gas phase. Another potential source in cold climates is road salt.…”