simpleGAMMA v1.0 – a reduced model of secondary organic  aerosol formation in the aqueous aerosol phase (aaSOA)

Woo, Joseph L.; McNeill, V. Faye

doi:10.5194/gmd-8-1821-2015

Cited by 40 publications

(64 citation statements)

References 43 publications

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“…V850 in particular has a well-established relationship with severe haze in Beijing reflecting the ventilation by the prevailing northerly (negative V850) wind (Li et al, 2018;Shen et al, 2018). High RH is not only an indicator of stagnation but also provides a high aerosol water content for secondary PM 2.5 formation to take place (Song et al, 2018;Wang et al, 2014;Woo & McNeill, 2015). High RH is not only an indicator of stagnation but also provides a high aerosol water content for secondary PM 2.5 formation to take place (Song et al, 2018;Wang et al, 2014;Woo & McNeill, 2015).…”

Section: Methodsmentioning

confidence: 97%

Predicting the Impact of Climate Change on Severe Wintertime Particulate Pollution Events in Beijing Using Extreme Value Theory

Pendergrass

Shen

Jacob

et al. 2019

Geophysical Research Letters

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We use extreme value theory to develop point process statistical models relating the probability of extreme winter particulate pollution events in Beijing (“winter haze”) to local meteorological variables. The models are trained with the 2009–2017 record of fine particulate matter concentrations (PM2.5) from the U.S. embassy. We find that 850‐hPa meridional wind velocity (V850) and relative humidity successfully predict the probability for 24‐hr average PM2.5 to exceed 300 μg/m3 (95th percentile of the frequency distribution) as well as higher thresholds. We apply the point process models to mid‐21st century climate projections from the Coupled Model Intercomparison Project Phase 5 model ensemble under two radiative forcing scenarios (RCP8.5 and RCP4.5). We conclude that 21st century climate change alone is unlikely to increase the frequency of severe PM2.5 pollution events (PM2.5 > 300 μg/m3) in Beijing and is more likely to marginally decrease the probability of such events.

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Section: Methodsmentioning

confidence: 97%

Predicting the Impact of Climate Change on Severe Wintertime Particulate Pollution Events in Beijing Using Extreme Value Theory

Pendergrass

Shen

Jacob

et al. 2019

Geophysical Research Letters

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“…Different approaches have been used to simplify the representation of cloud aqSOA chemistry. Condensed mechanisms include lumped processes or compounds to reduce the number of species [e.g., Deguillaume et al, 2009;Ervens et al, 2003;Woo and McNeill, 2015]. In global simulations of in-cloud mass formation, reduced aqueous-phase mechanisms have been used with a fixed droplet radius of 5 (or 6) μm over land and 10 μm over oceans [Myriokefalitakis et al, 2011;Roelofs et al, 1998].…”

Section: 1002/2017gl074233mentioning

confidence: 99%

A microphysical parameterization of aqSOA and sulfate formation in clouds

McVay

Ervens

2017

Geophysical Research Letters

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Sulfate and secondary organic aerosol (cloud aqSOA) can be chemically formed in cloud water. Model implementation of these processes represents a computational burden due to the large number of microphysical and chemical parameters. Chemical mechanisms have been condensed by reducing the number of chemical parameters. Here an alternative is presented to reduce the number of microphysical parameters (number of cloud droplet size classes). In‐cloud mass formation is surface and volume dependent due to surface‐limited oxidant uptake and/or size‐dependent pH. Box and parcel model simulations show that using the effective cloud droplet diameter (proportional to total volume‐to‐surface ratio) reproduces sulfate and aqSOA formation rates within ≤30% as compared to full droplet distributions; other single diameters lead to much greater deviations. This single‐class approach reduces computing time significantly and can be included in models when total liquid water content and effective diameter are available.

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“…More recent studies have modeled aqueous phase SOA production using empirically determined uptake coefficients or effective Henry's constants (when available) to estimate the reactive uptake of major isoprene products, such as IEPOX and glyoxal, in the inorganic aqueous phase (Marais et al, 2016;McNeill et al, 2012;Pye et al, 2013;Woo and McNeill, 2015). For example, McNeill et al (2012) developed the GAMMA (Gas-Aerosol Model for Mechanism Analysis) to predict the aqueous SOA production of isoprene in the presence of deliquesced ammonium sulfate.…”

Section: Introductionmentioning

confidence: 99%

Simulating the SOA formation of isoprene from partitioning and aerosol phase reactions in the presence of inorganics

Beardsley

Jang

2016

Atmos. Chem. Phys.

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Abstract. The secondary organic aerosol (SOA) produced by the photooxidation of isoprene with and without inorganic seed is simulated using the Unified Partitioning Aerosol Phase Reaction (UNIPAR) model. Recent work has found the SOA formation of isoprene to be sensitive to both aerosol acidity ([H + ], mol L −1 ) and aerosol liquid water content (LWC) with the presence of either leading to significant aerosol phase organic mass generation and large growth in SOA yields (Y SOA ). Classical partitioning models alone are insufficient to predict isoprene SOA formation due to the high volatility of photooxidation products and sensitivity of their mass yields to variations in inorganic aerosol composition. UNIPAR utilizes the chemical structures provided by a near-explicit chemical mechanism to estimate the thermodynamic properties of the gas phase products, which are lumped based on their calculated vapor pressure (eight groups) and aerosol phase reactivity (six groups). UNIPAR then determines the SOA formation of each lumping group from both partitioning and aerosol phase reactions (oligomerization, acid-catalyzed reactions and organosulfate formation) assuming a single homogeneously mixed organic-inorganic phase as a function of inorganic composition and VOC / NO x (VOC -volatile organic compound). The model is validated using isoprene photooxidation experiments performed in the dual, outdoor University of Florida Atmospheric PHotochemical Outdoor Reactor (UF APHOR) chambers. UNI-PAR is able to predict the experimental SOA formation of isoprene without seed, with H 2 SO 4 seed gradually titrated by ammonia, and with the acidic seed generated by SO 2 oxidation. Oligomeric mass is predicted to account for more than 65 % of the total organic mass formed in all cases and over 85 % in the presence of strongly acidic seed. The model is run to determine the sensitivity of Y SOA to [H + ], LWC and VOC / NO x , and it is determined that the SOA formation of isoprene is most strongly related to [H + ] but is dynamically related to all three parameters. For VOC / NO x > 10, with increasing NO x both experimental and simulated Y SOA increase and are found to be more sensitive to [H + ] and LWC. For atmospherically relevant conditions, Y SOA is found to be more than 150 % higher in partially titrated acidic seeds (NH 4 HSO 4 ) than in effloresced inorganics or in isoprene only.

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simpleGAMMA v1.0 – a reduced model of secondary organic aerosol formation in the aqueous aerosol phase (aaSOA)

Cited by 40 publications

References 43 publications

Predicting the Impact of Climate Change on Severe Wintertime Particulate Pollution Events in Beijing Using Extreme Value Theory

Predicting the Impact of Climate Change on Severe Wintertime Particulate Pollution Events in Beijing Using Extreme Value Theory

A microphysical parameterization of aqSOA and sulfate formation in clouds

Simulating the SOA formation of isoprene from partitioning and aerosol phase reactions in the presence of inorganics

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