Supplementary material to "Global-regional nested simulation of particle number concentration by combing microphysical processes with an evolving organic aerosol module"

Abstract. Aerosol microphysical processes are essential for the next generation of global and regional climate and air quality models to determine the particle size distribution. The contribution of organic aerosol (OA) to particle formation, mass and number concentration is one of the major uncertainties in current models. A new global-regional nested aerosol model was developed to simulate detailed microphysical processes. The model combined an advanced particle microphysics (APM) module and a volatility basis-set (VBS) organic aerosol module to calculate the kinetic condensation of low volatile organic compounds and equilibrium partitioning of semi-volatile organic compounds in a 3-dimensional (3-D) framework using global-regional nested domain. In addition to the condensation of sulfuric acid, equilibrium partitioning of nitrate and ammonium, and the coagulation process of particles, the microphysical processes of the organic aerosols are realistically represented in our new model. The model uses high-resolution size-bins to calculate the size distribution of new particles formed through nucleation and subsequent growth. The multi-scale nesting allows the model to use high resolution to simulate the particle formation processes in the urban atmosphere in the background of regional and global environments. Using the nested domains, the model reasonably reproduced the OA components from analysis of Aerosol Mass Spectrometry (AMS) measurements by Positive Matrix Factorization (PMF) and the particle number size distribution (PNSD) in Megacity Beijing during a period of about a month. Anthropogenic organic species accounted for 67 % of the OA of secondary particles formed by nucleation and subsequent growth, significantly larger than that of biogenic OA. Over the global scale, the model well predicted the particle number concentration in various environments. The microphysical module combined with VBS simulated the universal distribution of organic components among the different aerosol populations. Model results strongly suggest the importance of anthropogenic organic species in aerosol particle formation and growth at polluted urban sites and over the whole globe under the influence of anthropogenic source areas.

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Global–regional nested simulation of particle number concentration by combing microphysical processes with an evolving organic aerosol module

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-9343-2021 ◽

2021 ◽

Vol 21 (12) ◽

pp. 9343-9366

Author(s):

Xueshun Chen ◽

Fangqun Yu ◽

Wenyi Yang ◽

Yele Sun ◽

Huansheng Chen ◽

...

Keyword(s):

High Resolution ◽

Size Distribution ◽

Particle Number ◽

Particle Formation ◽

Number Concentration ◽

Particle Number Concentration ◽

Subsequent Growth ◽

Equilibrium Partitioning ◽

Organic Species ◽

Microphysical Processes

Abstract. Aerosol microphysical processes are essential for the next generation of global and regional climate and air quality models to determine particle size distribution. The contribution of organic aerosols (OAs) to particle formation, mass, and number concentration is one of the major uncertainties in current models. A new global–regional nested aerosol model was developed to simulate detailed microphysical processes. The model combines an advanced particle microphysics (APM) module and a volatility basis set (VBS) OA module to calculate the kinetic condensation of low-volatility organic compounds and equilibrium partitioning of semi-volatile organic compounds in a 3-D framework using global–regional nested domain. In addition to the condensation of sulfuric acid, the equilibrium partitioning of nitrate and ammonium, and the coagulation process of particles, the microphysical processes of the OAs are realistically represented in our new model. The model uses high-resolution size bins to calculate the size distribution of new particles formed through nucleation and subsequent growth. The multi-scale nesting enables the model to perform high-resolution simulations of the particle formation processes in the urban atmosphere in the background of regional and global environments. By using the nested domains, the model reasonably reproduced the OA components obtained from the analysis of aerosol mass spectrometry measurements through positive matrix factorization and the particle number size distribution in the megacity of Beijing during a period of approximately a month. Anthropogenic organic species accounted for 67 % of the OAs of secondary particles formed by nucleation and subsequent growth, which is considerably larger than that of biogenic OAs. On the global scale, the model well predicted the particle number concentration in various environments. The microphysical module combined with the VBS simulated the universal distribution of organic components among the different aerosol populations. The model results strongly suggest the importance of anthropogenic organic species in aerosol particle formation and growth at polluted urban sites and over the whole globe.

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Dimers in α-pinene secondary organic aerosol: effect of hydroxyl radical, ozone, relative humidity and aerosol acidity

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-4201-2014 ◽

2014 ◽

Vol 14 (8) ◽

pp. 4201-4218 ◽

Cited By ~ 83

Author(s):

K. Kristensen ◽

T. Cui ◽

H. Zhang ◽

A. Gold ◽

M. Glasius ◽

...

Keyword(s):

Molecular Weight ◽

Gas Phase ◽

High Molecular Weight ◽

Carboxylic Acids ◽

Particle Number ◽

Organic Aerosol ◽

Number Concentration ◽

Particle Number Concentration ◽

Aerosol Acidity ◽

Homogenous Nucleation

Abstract. The formation of secondary organic aerosol (SOA) from both ozonolysis and hydroxyl radical (OH)-initiated oxidation of α-pinene under conditions of high nitric oxide (NO) concentrations with varying relative humidity (RH) and aerosol acidity was investigated in the University of North Carolina dual outdoor smog chamber facility. SOA formation from ozonolysis of α-pinene was enhanced relative to that from OH-initiated oxidation in the presence of initially high-NO conditions. However, no effect of RH on SOA mass was evident. Ozone (O3)-initiated oxidation of α-pinene in the presence of ammonium sulfate (AS) seed coated with organic aerosol from OH-initiated oxidation of α-pinene showed reduced nucleation compared to ozonolysis in the presence of pure AS seed aerosol. The chemical composition of α-pinene SOA was investigated by ultra-performance liquid chromatography/electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-Q-TOFMS), with a focus on the formation of carboxylic acids and high-molecular weight dimers. A total of eight carboxylic acids and four dimers were identified, constituting between 8 and 12% of the total α-pinene SOA mass. OH-initiated oxidation of α-pinene in the presence of nitrogen oxides (NOx) resulted in the formation of highly oxidized carboxylic acids, such as 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA) and diaterpenylic acid acetate (DTAA). The formation of dimers was observed only in SOA produced from the ozonolysis of α-pinene in the absence of NOx, with increased concentrations by a factor of two at higher RH (50–90%) relative to lower RH (30–50%). The increased formation of dimers correlates with an observed increase in new particle formation at higher RH due to nucleation. Increased aerosol acidity was found to have a negligible effect on the formation of the dimers. SOA mass yield did not influence the chemical composition of SOA formed from α-pinene ozonolysis with respect to carboxylic acids and dimers. The results support the formation of the high-molecular weight dimers through gas-phase reactions of the stabilized Criegee Intermediate (sCI) formed from the ozonolysis of α-pinene. The high molecular weight and polar nature of dimers formed in the gas phase may explain increased particle number concentration as a result of homogenous nucleation. Since three of these dimers (i.e. pinyl-diaterpenyl dimer (MW 358), pinyl-diaterebyl dimer (MW 344) and pinonyl-pinyl dimer (MW 368)) have been observed in both laboratory-generated and ambient fine organic aerosol samples, we conclude that the dimers observed in this study can be used as tracers for the O3-initiated oxidation of α-pinene, and are therefore indicative of enhanced anthropogenic activities, and that the high molecular weight and low volatility dimers result in homogenous nucleation under laboratory conditions, increasing the particle number concentration.

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Dimer esters in α-pinene secondary organic aerosol: effect of hydroxyl radical, ozone, relative humidity and aerosol acidity

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-32529-2013 ◽

2013 ◽

Vol 13 (12) ◽

pp. 32529-32574 ◽

Cited By ~ 3

Author(s):

K. Kristensen ◽

T. Cui ◽

H. Zhang ◽

A. Gold ◽

M. Glasius ◽

...

Keyword(s):

Molecular Weight ◽

Gas Phase ◽

High Molecular Weight ◽

Carboxylic Acids ◽

Particle Number ◽

Organic Aerosol ◽

Number Concentration ◽

Particle Number Concentration ◽

Aerosol Acidity ◽

Homogenous Nucleation

Abstract. The formation of secondary organic aerosol (SOA) from both ozonolysis and hydroxyl radical (OH)-initiated oxidation of α-pinene under conditions of high nitric oxide (NO) concentrations with varying relative humidity (RH) and aerosol acidity was investigated in the University of North Carolina dual outdoor smog chamber facility. SOA formation from ozonolysis of α-pinene was enhanced relative to that from OH-initiated oxidation in the presence of initially high NO conditions. However, no effect of RH on SOA mass was evident. Ozone (O3)-initiated oxidation of α-pinene in the presence of ammonium sulfate (AS) seed coated with organic aerosol from OH-initiated oxidation of α-pinene showed reduced nucleation compared to ozonolysis in the presence of pure AS seed aerosol. The chemical composition of α-pinene SOA was investigated by ultra-performance liquid chromatography/electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-Q-TOFMS), with a focus on the formation of carboxylic acids and high-molecular weight dimer esters. A total of eight carboxylic acids and four dimer esters were identified, constituting between 8 and 12% of the total α-pinene SOA mass. OH-initiated oxidation of α-pinene in the presence of nitrogen oxides (NOx) resulted in the formation of highly oxidized carboxylic acids, such as 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA) and diaterpenylic acid acetate (DTAA). The formation of dimer esters was observed only in SOA produced from the ozonolysis of α-pinene in the absence of NOx, with increased concentrations by a~factor of two at higher RH (50–90%) relative to lower RH (30–50%). The increased formation of dimer esters correlates with an observed increase in new particle formation at higher RH due to nucleation. Increased aerosol acidity was found to have a negligible effect on the formation of the dimer esters. SOA mass yield did not influence the chemical composition of SOA formed from α-pinene ozonolysis with respect to carboxylic acids and dimer esters. The results support the formation of the high-molecular weight dimer esters through gas-phase reactions of the stabilized Criegee Intermediate (sCI) formed from the ozonolysis of α-pinene. The high molecular weight and polar nature of dimer esters formed in the gas-phase may explain increased particle number concentration as a~result of homogenous nucleation. Since three of these dimer esters (i.e., pinyl-diaterpenyl ester (MW 358), pinyl-diaterebyl ester (MW 344) and pinonyl-pinyl ester (MW 368)) have been observed in both laboratory-generated and ambient fine organic aerosol samples, we conclude that the dimer esters observed in this study can be used as tracers for the O3-initiated oxidation of α-pinene, and are therefore indicative of enhanced anthropogenic activities, and that the high molecular weight and low volatility esters result in homogenous nucleation under laboratory conditions, increasing the particle number concentration.

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Simulating aerosol microphysics with the ECHAM4/MADE GCM – Part II: Results from a first multiannual simulation of the submicrometer aerosol

Atmospheric Chemistry and Physics ◽

10.5194/acp-6-5495-2006 ◽

2006 ◽

Vol 6 (12) ◽

pp. 5495-5513 ◽

Cited By ~ 13

Author(s):

A. Lauer ◽

J. Hendricks

Keyword(s):

Size Distribution ◽

Black Carbon ◽

Wet Deposition ◽

Mass Concentration ◽

Particle Number ◽

Lower Troposphere ◽

Model System ◽

Number Concentration ◽

Particle Number Concentration ◽

Microphysical Processes

Abstract. First results of a multiannual integration with the new global aerosol model system ECHAM4/MADE are presented. This model system enables simulations of the particle number concentration and size-distribution, which is a fundamental innovation compared to previous global model studies considering aerosol mass cycles only. The data calculated by the model provide detailed insights into the properties of the global submicrometer aerosol regarding global burden, chemical composition, atmospheric residence time, particle number concentration and size-distribution. The aerosol components considered by the model are sulfate (SO4), nitrate (NO3), ammonium (NH4), black carbon (BC), organic matter (OM), mineral dust, sea salt and aerosol water. The simulated climatological annual mean global atmospheric burdens (residence times) of the dominant submicrometer aerosol components are 2.25 Tg (4.5 d) for SO4, 0.46 Tg (4.5 d) for NH4, 0.26 Tg (6.6 d) for BC, and 1.77 Tg (6.5 d) for OM. The contributions of individual processes such as emission, nucleation, condensation or dry and wet deposition to the global sources and sinks of specific aerosol components and particle number concentration are quantified. Based on this analysis, the significance of aerosol microphysical processes (nucleation, condensation, coagulation) is evaluated by comparison to the importance of other processes relevant for the submicrometer aerosol on the global scale. The results reveal that aerosol microphysics are essential for the simulation of the particle number concentration and important but not vital for the simulation of particle mass concentration. Hence aerosol microphysics should be taken into account in simulations of atmospheric processes showing a significant dependence on aerosol particle number concentration. The analysis of the vertical variation of the microphysical net production and net depletion rates performed for particle number concentration, sulfate mass and black carbon mass concentration unveils the dominant source and sink regions. Prominent features can be attributed to dominant microphysical processes such as nucleation in the upper troposphere or wet deposition in the lower troposphere. Regions of efficient coagulation can be identified.

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