Impact of chamber wall loss of gaseous organic compounds on secondary organic aerosol formation: explicit modeling of SOA formation from alkane and alkene oxidation

Y S La,J Lee-Taylor,V Lannuque,P J Ziemann,S Madronich,M Camredon,B Aumont,R Valorso,A Matsunaga,A Hodzic

doi:10.5194/acp-16-1417-2016

Abstract

Abstract. Recent studies have shown that low volatility gas-phase species can be lost onto the smog chamber wall surfaces. Although this loss of organic vapors to walls could be substantial during experiments, its effect on secondary organic aerosol (SOA) formation has not been well characterized and quantified yet. Here the potential impact of chamber walls on the loss of gaseous organic species and SOA formation has been explored using the Generator for Explicit Chemistry and Kinetics of the Organics in the Atmosphere (GECKO-A) modeling tool, which explicitly represents SOA formation and gas–wall partitioning. The model was compared with 41 smog chamber experiments of SOA formation under OH oxidation of alkane and alkene series (linear, cyclic and C12-branched alkanes and terminal, internal and 2-methyl alkenes with 7 to 17 carbon atoms) under high NOx conditions. Simulated trends match observed trends within and between homologous series. The loss of organic vapors to the chamber walls is found to affect SOA yields as well as the composition of the gas and the particle phases. Simulated distributions of the species in various phases suggest that nitrates, hydroxynitrates and carbonylesters could substantially be lost onto walls. The extent of this process depends on the rate of gas–wall mass transfer, the vapor pressure of the species and the duration of the experiments. This work suggests that SOA yields inferred from chamber experiments could be underestimated up a factor of 2 due to the loss of organic vapors to chamber walls.

Highlights

Secondary organic aerosols (SOAs) represent a major fraction of the fine particulate matter mass (e.g., Jimenez et al, 2009), contributing to the physicochemical properties of aerosols and to their impact on human health, climate and visibility
secondary organic aerosol (SOA) yield is defined as the ratio of SOA mass produced to the mass of HC
A comparison of the experimental and the simulated final SOA yields is presented in Fig. 7

Summary

Introduction

Secondary organic aerosols (SOAs) represent a major fraction of the fine particulate matter mass (e.g., Jimenez et al, 2009), contributing to the physicochemical properties of aerosols and to their impact on human health, climate and visibility. To assess and improve our knowledge of SOA formation, atmospheric chambers are widely used to perform controlled experiments of SOA formation from various VOCs and IVOCs. To assess and improve our knowledge of SOA formation, atmospheric chambers are widely used to perform controlled experiments of SOA formation from various VOCs and IVOCs These experiments provide kinetic and thermodynamic data, i.e., kinetic constants, branching ratios and partitioning coefficients (e.g., Atkinson and Arey, 2003; Aschmann et al, 2011), needed to design deterministic SOA models. Experiments performed in atmospheric chambers provide an ideal data set for the evaluation of deterministic SOA formation models (e.g., Camredon et al, 2010; Valorso et al, 2011; Jenkin et al, 2015) and the development of SOA formation parameterizations for chemical transport models (CTMs) at regional and global scale (e.g., Zhang and Seinfeld, 2013; Cappa and Wilson, 2012; Donahue et al, 2011; Santiago et al, 2012).

Objectives

Methods

Results

Conclusion