Influence of relative humidity on heterogeneous kinetics of NO₂ on kaolin and hematite

Abstract

In order to obtain reliable kinetic parameters, it is required to measure the reaction kinetics of important heterogeneous reactions at ambient relative humidity (RH). In this study, the uptake coefficients and HONO yields for the heterogeneous reaction of NO 2 on kaolin and hematite were measured at RH from 7% to 74% and at ambient pressure in the dark using a coated-wall flow tube reactor. The initial true uptake coefficient (g t,ini ) of NO 2 at RH 7% was measured to be (1.44 AE 0.10) Â 10 À7 and (1.58 AE 0.13) Â 10 À6 on kaolin and hematite, respectively, while it decreased notably on both minerals, accompanied by an increase of HONO yields, as RH increased. The average g t,ini at 32-74% RH was (4.42 AE 1.17) Â 10 À8 and (2.83 AE 0.84) Â 10 À7 on kaolin and hematite, respectively. The corresponding mean HONO yield was (36.0 AE 16.1)% and (75.9 AE 3.32)%, respectively.

Heterogeneous Reaction of SO2 on Manganese Oxides: the Effect of Crystal Structure and Relative Humidity

“…horizontal cylindrical coated-wall flow tube reactor, which has been described in detail elsewhere 56, 57 . The temperature was maintained at 298 K by circulating water through the outer jacket of the flow tube reactor.…”

Heterogeneous reactions of mineral dust aerosol: implications for tropospheric oxidation capacity

“…(1). However, deactivation of mineral dust surfaces has been reported for a variety of trace gases by experiments using particle ensembles deposited on a substrate (Underwood et al, 2001;Hanisch and Crowley, 2003a;Ndour et al, 2009;Tang et al, 2010;Zhou et al, 2012;Romanias et al, 2013;Liu et al, 2015). Therefore, uptake coefficients are normally set to be time dependent (instead of assuming to be a constant), such that Eq.…”

“…For example, dust aerosol particles can influence the radiative balance of the Earth system directly by scattering and absorbing solar and terrestrial radiation (Balkanski et al,11728 M. Tang et al: Heterogeneous reactions of mineral dust aerosol as cloud condensation nuclei (CCN) to form cloud droplets (Koehler et al, 2009;Kumar et al, 2009;Twohy et al, 2009;Garimella et al, 2014;Tang et al, 2016a) and ice nucleation particles (INPs) to form ice particles (DeMott et al, 2003;Hoose and Moehler, 2012;Murray et al, 2012;Ladino et al, 2013;DeMott et al, 2015). Mineral dust particles are believed to be the dominant ice nucleation particles in the troposphere (Hoose et al, 2010;Creamean et al, 2013;Cziczo et al, 2013), therefore having a large impact on the radiative balance, precipitation, and the hydrological cycle (Rosenfeld et al, 2001;Lohmann and Feichter, 2005;Rosenfeld et al, 2008). In addition, deposition of mineral dust is a major source for several important nutrient elements (e.g., Fe and P) in remote regions such as open-ocean waters and the Amazon Mahowald et al, 2005Mahowald et al, , 2008Boyd and Ellwood, 2010;Nenes et al, 2011;Schulz et al, 2012;Shi et al, 2012), strongly affecting several biogeochemical cycles and the climate system of the Earth Mahowald, 2011;Mahowald et al, 2011;Schulz et al, 2012).…”

Emission of nitrous acid from soil and biological soil crusts represents an important source of HONO in the remote atmosphere in Cyprus

“…humic acid, minerals, proteins and organically coated particles (Ammann et al, 1998;Arens et al, 2001;Aubin et al, 2007;Bröske et al, 2003;Han et al, 2016;Kalberer et al, 1999;Kleffmann et al, 1999;Kleffmann and Wiesen, 2005;Lelièvre et al, 2004;Kinugawa et al, 2011;Liu et al, 2015;Wang et al, 2003;Yabushita et al, 2009;Meusel et al, 2017). Light can activate some of these surfaces (humic acid, proteins and other organic compounds, titanium dioxide, soot), which enhances NO 2 uptake and HONO production (George et al, 2005;Langridge et al, 2009;Monge et al, 2010;Ndour et al, 2008;Ramazan et al, 2004;Stemmler et al, 2007;Kebede et al, 2013;Meusel et al, 2017).…”