Heterogeneous Uptake of Gaseous N₂O₅by (NH₄)₂SO₄, NH₄HSO₄, and H₂SO₄Aerosols

Abstract

The heterogeneous uptake of gaseous N 2 O 5 by ammonium sulfate [(NH 4 ) 2 SO 4 ], ammonium bisulfate [NH 4 HSO 4 ], and sulfuric acid [H 2 SO 4 ] aerosols as a function of relative humidity has been investigated at room temperature and atmospheric pressure. Ammonium-containing aerosols were generated by a constantoutput atomizer and conditioned by passing through a diffusion dryer. Sulfuric acid aerosols were produced by the homogeneous reaction of SO 3 and H 2 O in a borosilicate vessel. Addition of a dry or wet N 2 flow controlled the relative humidity (RH) of these aerosol flows. Using a chemical ionization mass spectrometer (CIMS) for N 2 O 5 concentration monitoring and a scanning mobility particle spectrometer (SMPS) for aerosol characterization, reaction probabilities (γ) in the range of 0.001 to 0.1 for the uptake of N 2 O 5 were determined as a function of RH. The results are expressed as follows: γ[(NH 4 ) 2 SO 4 ] ) 2.79 × 10 -4 + 1.30 × 10 -4 × (RH) -3.43 × 10 -6 × (RH) 2 + 7.52 × 10 -8 × (RH) 3 , γ[NH 4 HSO 4 ] ) 2.07 × 10 -3 -1.48 × 10 -4 × (RH) + 8.26 × 10 -6 × (RH) 2 , and γ[H 2 SO 4 ] ) 0.052 -2.79 × 10 -4 × (RH). We suggest that the water content and phase in the ammonium-containing aerosols control the reactivity of N 2 O 5 while liquid-phase ionic reactions primarily dominate the uptake in sulfuric acid aerosols.

Hygroscopicity and chemical composition of Antarctic sub-micrometre aerosol particles and observations of new particle formation

“…Additionally the particle chemistry, and furthermore hygroscopic properties, are affected by aqueous phase reactions taking place in liquid particles (e.g. Kane et al, 2001;Volkamer et al, 2009). Findings by Buchholz et al (2009) suggest that secondary organics generated in sunny conditions are more hygroscopic and also more CCN active than those generated under cloudy conditions.…”

Trace gas and aerosol interactions in the fully coupled model of aerosol‐chemistry‐climate ECHAM5‐HAMMOZ: 1. Model description and insights from the spring 2001 TRACE‐P experiment

“…For instance, the total gas-to-particle transfer rate of N 2 O 5 K N 2 O 5 is calculated as the sum of the specific K N 2 O 5 ,i x as follows: [29] We implemented the reactions of HO 2 , NO 2 , NO 3 on wet aerosol particles (e.g., all the soluble modes (NS, KS, AS, and CS) in the model, independently of their composition) with the uptake coefficients of 0.2, 10 À4 and 10 À3 , respectively, following Jacob [2000]. The uptake of N 2 O 5 on aerosol particles follows Evans and Jacob [2005] and Liao and Seinfeld [2005], i.e., different coefficients are used for sulfate [Kane et al, 2001;Hallquist et al, 2003], organic carbon [Thornton et al, 2003], black carbon [Sander et al, 2003], sea salt [Atkinson et al, 2004], and mineral dust [Bauer et al, 2004]. The O 3 uptake coefficient on mineral dust is set to 10 À5 following Bauer et al [2004].…”

A parameterization of the heterogeneous hydrolysis of N<sub>2</sub>O<sub>5</sub> for mass-based aerosol models: improvement of particulate nitrate prediction

“…Recently, Morgan et al (2015) demonstrated that this influence of chloride may not be represented properly, and the "high" O : C regime defined in Gaston et al (2014) was scarcely observed over north-western Europe by airborne regional measurements. Several laboratory studies reported that γ N 2 O 5 substantially varies with temperature, RH, and particle composition (Mentel et al, 1999;Kane et al, 2001;Hallquist et al, 2003;Chang et al, 2011;Brown and Stutz, 2012;Gaston et al, 2014). Davis et al (2008) developed a parameterization scheme (Davis08) of γ N 2 O 5 for aerosols containing nitrate, sulfate, and ammonium.…”

“…Davis et al (2008) developed a parameterization scheme (Davis08) of γ N 2 O 5 for aerosols containing nitrate, sulfate, and ammonium. It was developed on the basis of numerous previous laboratory studies (Badger et al, 2006;Folkers et al, 2003;Hallquist et al, 2003;Folkers, 2002;Kane et al, 2001;Hu and Abbatt, 1997;Mozurkewich and Calvert, 1988) with respect to temperature, RH, and particle compositions.…”

“…Evans and Jacob (2005) proposed a parameterization scheme (EJ05) that has an extensive description of aerosol composition to improve the GEOS-CHEM simulations. EJ05 included γ N 2 O 5 of dust (Bauer et al, 2004), sea salt (Sander et al, 2003), sulfate (Hallquist et al, 2003;Kane et al, 2001), elemental carbon (EC; Sander et al, 2003), and organic carbon (OC; Thornton et al, 2003) and also took into account the dependence of γ N 2 O 5 on RH. However, γ N 2 O 5 of nitrate and its dependence on temperature were not carefully considered in EJ05.…”