Cloud Processing of Gases and Aerosols in Air Quality Modeling

The representations of cloud processing of gases and aerosols in some of the current state-of-the-art regional air quality models in North America and Europe are reviewed. Key processes reviewed include aerosol activation (or nucleation scavenging of aerosols), aqueous-phase chemistry, and wet depos...

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Main Authors: Leiming Zhang, Craig Stroud, Wanmin Gong
Format: Article
Language:English
Published: MDPI AG 2011-10-01
Series:Atmosphere
Subjects:
Online Access:http://www.mdpi.com/2073-4433/2/4/567/
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author Leiming Zhang
Craig Stroud
Wanmin Gong
author_facet Leiming Zhang
Craig Stroud
Wanmin Gong
author_sort Leiming Zhang
collection DOAJ
description The representations of cloud processing of gases and aerosols in some of the current state-of-the-art regional air quality models in North America and Europe are reviewed. Key processes reviewed include aerosol activation (or nucleation scavenging of aerosols), aqueous-phase chemistry, and wet deposition/removal of atmospheric tracers. It was found that models vary considerably in the parameterizations or algorithms used in representing these processes. As an emerging area of research, the current understanding of the uptake of water soluble organics by cloud droplets and the potential aqueous-phase reaction pathways leading to the atmospheric secondary organic aerosol (SOA) formation is also reviewed. Sensitivity tests using the AURAMS model have been conducted in order to assess the impact on modeled regional particulate matter (PM) from: (1) the different aerosol activation schemes, (2) the different below-cloud particle scavenging algorithms, and (3) the inclusion of cloud processing of water soluble organics as a potential pathway for the formation of atmospheric SOA. It was found that the modeled droplet number concentrations and ambient PM size distributions were strongly affected by the use of different aerosol activation schemes. The impact on the modeled average ambient PM mass concentration was found to be limited in terms of averaged PM2.5 concentration (~a few percents) but more significant in terms of PM1.0 (up to 10 percents). The modeled ambient PM was found to be moderately sensitive to the below-cloud particle scavenging algorithms, with relative differences up to 10% and 20% in terms of PM2.5 and PM10, respectively, when using the two different algorithms for the scavenging coefficient (Λ) corresponding to the lower and upper bounds in the parameterization for Λ. The model simulation with the additional cloud uptake and processing of water-soluble organic gases was shown to improve the evaluation statistics for modeled PM2.5 OA compared to the IMPROVE network data, and it was demonstrated that the cloud processing of water-soluble organics can indeed be an important mechanism in addition to the traditional secondary organic gas uptake to the particle organic phase.
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spelling doaj.art-135ac79bc6804d078bd6eeec7e28bec02022-12-22T01:21:36ZengMDPI AGAtmosphere2073-44332011-10-012456761610.3390/atmos2040567Cloud Processing of Gases and Aerosols in Air Quality ModelingLeiming ZhangCraig StroudWanmin GongThe representations of cloud processing of gases and aerosols in some of the current state-of-the-art regional air quality models in North America and Europe are reviewed. Key processes reviewed include aerosol activation (or nucleation scavenging of aerosols), aqueous-phase chemistry, and wet deposition/removal of atmospheric tracers. It was found that models vary considerably in the parameterizations or algorithms used in representing these processes. As an emerging area of research, the current understanding of the uptake of water soluble organics by cloud droplets and the potential aqueous-phase reaction pathways leading to the atmospheric secondary organic aerosol (SOA) formation is also reviewed. Sensitivity tests using the AURAMS model have been conducted in order to assess the impact on modeled regional particulate matter (PM) from: (1) the different aerosol activation schemes, (2) the different below-cloud particle scavenging algorithms, and (3) the inclusion of cloud processing of water soluble organics as a potential pathway for the formation of atmospheric SOA. It was found that the modeled droplet number concentrations and ambient PM size distributions were strongly affected by the use of different aerosol activation schemes. The impact on the modeled average ambient PM mass concentration was found to be limited in terms of averaged PM2.5 concentration (~a few percents) but more significant in terms of PM1.0 (up to 10 percents). The modeled ambient PM was found to be moderately sensitive to the below-cloud particle scavenging algorithms, with relative differences up to 10% and 20% in terms of PM2.5 and PM10, respectively, when using the two different algorithms for the scavenging coefficient (Λ) corresponding to the lower and upper bounds in the parameterization for Λ. The model simulation with the additional cloud uptake and processing of water-soluble organic gases was shown to improve the evaluation statistics for modeled PM2.5 OA compared to the IMPROVE network data, and it was demonstrated that the cloud processing of water-soluble organics can indeed be an important mechanism in addition to the traditional secondary organic gas uptake to the particle organic phase.http://www.mdpi.com/2073-4433/2/4/567/cloud processesaerosol activationaqueous-phase chemistrysulphatesecondary organic aerosolcloud-aerosol interactionwet deposition
spellingShingle Leiming Zhang
Craig Stroud
Wanmin Gong
Cloud Processing of Gases and Aerosols in Air Quality Modeling
Atmosphere
cloud processes
aerosol activation
aqueous-phase chemistry
sulphate
secondary organic aerosol
cloud-aerosol interaction
wet deposition
title Cloud Processing of Gases and Aerosols in Air Quality Modeling
title_full Cloud Processing of Gases and Aerosols in Air Quality Modeling
title_fullStr Cloud Processing of Gases and Aerosols in Air Quality Modeling
title_full_unstemmed Cloud Processing of Gases and Aerosols in Air Quality Modeling
title_short Cloud Processing of Gases and Aerosols in Air Quality Modeling
title_sort cloud processing of gases and aerosols in air quality modeling
topic cloud processes
aerosol activation
aqueous-phase chemistry
sulphate
secondary organic aerosol
cloud-aerosol interaction
wet deposition
url http://www.mdpi.com/2073-4433/2/4/567/
work_keys_str_mv AT leimingzhang cloudprocessingofgasesandaerosolsinairqualitymodeling
AT craigstroud cloudprocessingofgasesandaerosolsinairqualitymodeling
AT wanmingong cloudprocessingofgasesandaerosolsinairqualitymodeling