Formulation of a Second-Generation Reactive Plume and Visibility Model

Seigneur, Christian; Wu, Xiaohong A.; Constantinou, E.; Gillespie, Patricia A.; Bergström, R. W.; Sykes, Ian; Venkatram, Akula; Karamchandani, Prakash

doi:10.1080/10473289.1997.10464433

Cited by 23 publications

(17 citation statements)

References 22 publications

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“…In the nonbulk equilibrium approach (also referred to as the size‐resolved equilibrium approach; see Moya et al [2002]), particles in different size sections may have different chemical compositions. The bulk equilibrium approach of Binkowski and Shankar [1995] and the simple bulk equilibrium approach of Hudischewskyj and Seigneur [1989] and Seigneur et al [1997] (the latter approach was used in the sensitivity study in this work and is referred to as a simple bulk equilibrium approach hereafter) are examples of simple bulk equilibrium approaches, in which the transferred material is allocated to the particle size distribution using weighting factors that are derived based on either initial particle mass/surface area or a given distribution. In more advanced bulk equilibrium approaches such as those used in UAM‐AERO [ Lurmann et al , 1997] and CIT [ Meng et al , 1998] (the latter approach is referred to as the CIT bulk equilibrium hereafter), the weighting factors are calculated based on condensational growth law using diffusion‐limited assumptions, accounting more or less for the nonequilibrium between the bulk gas phase and particles in a given size range.…”

Section: Formulation Of Madridmentioning

confidence: 99%

Development and application of the Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID)

2004

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[1] A new aerosol model, the Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID) has been developed to simulate atmospheric particulate matter (PM). MADRID and the Carnegie-Mellon University (CMU) bulk aqueous-phase chemistry have been incorporated into the three-dimensional Models-3/Community Multiscale Air Quality model (CMAQ). The resulting model, CMAQ-MADRID, is applied to simulate the August 1987 episode in the Los Angeles basin. Model performance for ozone and PM is consistent with current performance standards. However, organic aerosol was underpredicted at most sites owing to underestimation of primary organic PM emissions and secondary organic aerosol (SOA) formation. Nitrate concentrations were also sometimes underpredicted, mainly owing to overpredictions in vertical mixing, underpredictions in relative humidity, and uncertainties in the emissions of primary pollutants. Including heterogeneous reactions changed hourly O 3 by up to 17% and 24-hour average PM 2.5 , sulfate 2.5 , and nitrate 2.5 concentrations by up to 3, 7, and 19%, respectively. A SOA module with a mechanistic representation provides results that are more consistent with observations than that with an empirical representation. The movingcenter scheme for particle growth predicts more accurate size distributions than a typical semi-Lagrangian scheme, which causes an upstream numerical diffusion. A hybrid approach that simulates dynamic mass transfer for coarse PM but assumes equilibrium for fine PM can predict a realistic particle size distribution under most conditions, and the same applies under conditions with insignificant concentrations of reactive coarse particles to a bulk equilibrium approach that allocates transferred mass to different size sections based on condensational growth law. In contrast, a simple bulk equilibrium approach that allocates transferred mass based on a given distribution tends to cause a downstream numerical diffusion in the predicted particle size distribution.

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Section: Formulation Of Madridmentioning

confidence: 99%

Development and application of the Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID)

2004

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“…Seigneur et al 1997 . Several attempts have been made to minimize numerical diffusion, and the 3 approache s that are currently used in 3-D air quality models can be described as follows.…”

Section: Formulation Of the Condensational Growth Algorithmsmentioning

confidence: 99%

“…Seigneur et al 1997 . In the equilibrium approach, the mass transfer between the bulk gas phase and the particle surface is assumed to be instantaneous so that there is no concentration gradient between the bulk gas phase and the particle surface.…”

Section: Formulation Of Gas R R R R R Particle Mass Transfermentioning

confidence: 99%

Simulation of Aerosol Dynamics: A Comparative Review of Algorithms Used in Air Quality Models

Zhang¹,

Seigneur²,

Seinfeld³

et al. 1999

Aerosol Science and Technology

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204

177

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ABSTRACT. A comparative review of algorithms currently used in air qu ality models to simulate aerosol dynamics is presented. This review addresses coagulation, condensational growth, nucleation, an d gas r r r r rparticle mass transfer. Two major approaches are used in air qu ality models to represent the particle size ( ) distribution: 1 the sectional approach in wh ich the size distribution is discretized into sections and particle properties are assumed to be constant over particle size ( ) sections and 2 the modal approach in wh ich the size distribution is approximated by several modes and particle properties are assumed to be uniform in each mode. The section al approach is accur ate for coagulation an d can reproduce the major ch aracteristics of the evolution of the particle size distribution for condensational growth with the moving-center an d hybrid algorithms. For coagulation and condensation al growth, the modal approach provides more accurate results when the standard deviations of the modes are allowed to vary than it does when they are ® xed. Predictions of H SO nucleation rates are highly sensitive to environ -2 4 mental variables and simulation of relative rates of condensation on existing particles and nucleation is a preferable approach. Explicit treatment of mass transfer is recommended for cases where volatile species undergo different equilib-( rium reactions in different particle size ranges e.g., in the presence of coarse salt ) particles . The results of this study provide useful information for use in selecting algorithms to simulate aerosol dynamics in air qu ality models and for improving the accuracy of existing algorithms.

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“…6 The chemistry of the plume in the initial stage (plume rise phase) includes the reactions between nitric oxide (NO), nitrogen dioxide (NO 2 ), oxygen (O 2 ), and ozone (O 3 ). 4 …”

Section: Reactive Plume Modelmentioning

confidence: 99%

“…We used the Reactive and Optics Model of Emissions (ROME) 4 to perform the study. ROME includes state-ofthe-science formulations of plume rise and dispersion using second-order closure algorithms, aerosol dynamics, and atmospheric chemistry.…”

Section: Reactive Plume Modelmentioning

confidence: 99%

Simulation of Sulfate and Nitrate Chemistry in Power Plant Plumes

Karamchandani

Seigneur

1999

Journal of the Air & Waste Management Association

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IMPLICATIONSThe recent revisions to the National Ambient Air Quality Standards for PM will require the use of sophisticated models that can simulate the formation of secondary PM 2.5 to examine the effect of emission control strategies and field measurement studies to evaluate and improve these models. Some components of secondary PM 2.5 include sulfate and nitrate particles that can be formed from SO 2 and NO x emissions from a variety of sources, including coal-fired power plants. However, the chemistry governing particulate formation in power plant plumes can be significantly different from that in the background. ABSTRACTThe rate of formation of secondary particulate matter (PM) in power plant plumes varies as the plume material mixes with the background air. Consequently, the rate of oxidation of sulfur dioxide (SO 2 ) and nitrogen dioxide (NO 2 ) to sulfate and nitric acid, respectively, can be very different in plumes and in the background air (i.e., air outside the plume). In addition, the formation of sulfate and nitric acid in a power plant plume is a strong function of the chemical composition of the background air and the prevailing meteorological conditions.We describe the use of a reactive plume model, the Reactive and Optics Model of Emissions, to simulate sulfate and nitrate formation in a power plant plume for a variety of background conditions. We show that SO 2 and NO 2 oxidation rates are maximum in the background air for volatile organic compound (VOC)-limited airsheds but are maximum at some downwind distance in the plume when the background air is nitrogen oxide (NO x )-limited. Our analysis also shows that it is essential to obtain measurements of background concentrations of ozone, aldehydes, peroxyacetyl nitrate, and other VOCs to properly describe plume chemistry. INTRODUCTIONThe recently promulgated revisions to the National Ambient Air Quality Standards (NAAQS) for particulate matter (PM) include two new standards for PM 2.5 (particles with a nominal aerodynamic diameter of 2.5 µm and smaller). A significant fraction of particles in this size range are formed in the atmosphere from the oxidation of primary emissions of sulfur dioxide (SO 2 ), nitrogen oxides (NO x ), and volatile organic compounds (VOCs). Coal-fired power plants can be large emitters of SO 2 and NO x . However, the rate of formation of secondary PM in power plant plumes can be significantly lower than in the background air (the air outside the plume), particularly in the near stack region.1-3 The PM formation rate in the plume will depend on the rate of mixing of the plume material with the background air and on the chemical composition of the background air. Unless these subgrid-scale processes are explicitly incorporated in the three-dimensional Eulerian air quality models that are likely to be applied for PM 2.5 modeling, the rate of oxidation of SO 2 and NO x to secondary PM in plumes will be overestimated, since most Eulerian models assume that the plume is instantaneously mixed over a large grid-cell volume. In...

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Formulation of a Second-Generation Reactive Plume and Visibility Model

Cited by 23 publications

References 22 publications

Development and application of the Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID)

Development and application of the Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID)

Simulation of Aerosol Dynamics: A Comparative Review of Algorithms Used in Air Quality Models

Simulation of Sulfate and Nitrate Chemistry in Power Plant Plumes

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