Recent Advances in Understanding Secondary Organic Aerosol: Implications for global climate forcing

TitleRecent Advances in Understanding Secondary Organic Aerosol: Implications for global climate forcing
Publication TypeJournal Article
Year of Publication2017
AuthorsShrivastava, Manish, Kappa Christopher D., Fan Jiwen, Goldstein Allen H., Guenther Alex B., Jimenez Jose L., Kuang Chongai, Laskin Alexander, Martin Scot T., Ng Nga Lee, Petaja Tuukka, Pierce Jeffrey R., Rasch Philip J., Roldin Pontus, Seinfeld John H., Shilling John, Smith James N., Thornton Joel A., Volkamer Rainer, Wang Jian, Worsnop Douglas R., Zaveri Rahul A., Zelenyuk Alla, and Zhang Qi
JournalReviews of Geophysics
VolumeAccepted
Date Published05/2017
Abstract

Anthropogenic emissions and land-use changes have modified atmospheric aerosol concentrations and size distributions over time. Understanding pre-industrial conditions and changes in organic aerosol due to anthropogenic activities is important because these features 1) influence estimates of aerosol radiative forcing and 2) can confound estimates of the historical response of climate to increases in greenhouse gases. Secondary organic aerosol (SOA), formed in the atmosphere by oxidation of organic gases, represents a major fraction of global submicron-sized atmospheric organic aerosol. Over the past decade, significant advances in understanding SOA properties and formation mechanisms have occurred through measurements, yet current climate models typically do not comprehensively include all important processes. This review summarizes some of the important developments during the past decade in understanding SOA formation. We highlight the importance of some processes that influence the growth of SOA particles to sizes relevant for clouds and radiative forcing, including: formation of extremely low-volatility organics in the gas phase; acid-catalyzed multi-phase chemistry of isoprene epoxydiols (IEPOX); particle-phase oligomerization; and physical properties such as volatility and viscosity. Several SOA processes highlighted in this review are complex and interdependent, and have non-linear effects on the properties, formation and evolution of SOA. Current global models neglect this complexity and non-linearity, and thus are less likely to accurately predict the climate forcing of SOA, and project future climate sensitivity to greenhouse gases. Efforts are also needed to rank the most influential processes and non-linear process-related interactions, so that these processes can be accurately represented in atmospheric chemistry-climate models.

URLhttp://onlinelibrary.wiley.com/doi/10.1002/2016RG000540/full
DOI10.1002/2016RG000540
Journal: Reviews of Geophysics
Volume: Accepted

Anthropogenic emissions and land-use changes have modified atmospheric aerosol concentrations and size distributions over time. Understanding pre-industrial conditions and changes in organic aerosol due to anthropogenic activities is important because these features 1) influence estimates of aerosol radiative forcing and 2) can confound estimates of the historical response of climate to increases in greenhouse gases. Secondary organic aerosol (SOA), formed in the atmosphere by oxidation of organic gases, represents a major fraction of global submicron-sized atmospheric organic aerosol. Over the past decade, significant advances in understanding SOA properties and formation mechanisms have occurred through measurements, yet current climate models typically do not comprehensively include all important processes. This review summarizes some of the important developments during the past decade in understanding SOA formation. We highlight the importance of some processes that influence the growth of SOA particles to sizes relevant for clouds and radiative forcing, including: formation of extremely low-volatility organics in the gas phase; acid-catalyzed multi-phase chemistry of isoprene epoxydiols (IEPOX); particle-phase oligomerization; and physical properties such as volatility and viscosity. Several SOA processes highlighted in this review are complex and interdependent, and have non-linear effects on the properties, formation and evolution of SOA. Current global models neglect this complexity and non-linearity, and thus are less likely to accurately predict the climate forcing of SOA, and project future climate sensitivity to greenhouse gases. Efforts are also needed to rank the most influential processes and non-linear process-related interactions, so that these processes can be accurately represented in atmospheric chemistry-climate models.

DOI: 10.1002/2016RG000540
Year of Publication: 2017
Citation:
Shrivastava, M, CD Kappa, J Fan, AH Goldstein, AB Guenther, JL Jimenez, C Kuang, A Laskin, ST Martin, NL Ng, T Petaja, JR Pierce, PJ Rasch, P Roldin, JH Seinfeld, J Shilling, JN Smith, JA Thornton, R Volkamer, J Wang, DR Worsnop, RA Zaveri, A Zelenyuk, and Q Zhang.  2017.  "Recent Advances in Understanding Secondary Organic Aerosol: Implications for global climate forcing."  Reviews of Geophysics Accepted, doi:10.1002/2016RG000540.