Atmospheric Gas-Aerosol Equilibrium I. Thermodynamic Model

Kim, Yong Pyo; Seinfeld, John H.; Saxena, Pradeep

doi:10.1080/02786829308959628

Cited by 345 publications

(212 citation statements)

References 52 publications

Supporting

Mentioning

208

Contrasting

Order By: Relevance

“…The existence of solid species in SCAPE is mainly determined by three thermodynamic properties: (1) the equilibrium constant of letovicite, (2) the water content data of (NH4),S04 and H,S04 and the accuracy of the ZSR method, and (3) activity coefficients of NH;, H + , HSO;, and SO:-ions. Water activity prediction by the ZSR method was good as shown in Figure 6, and the activity coefficient estimation method used, the Pitzer method, is shown to be more accurate than other available methods, including the K-M method (Kim et al, 1993a). Therefore, it seems reasonable to suspect the equilibrium constant is the source of uncertainty.…”

Section: Resultsmentioning

confidence: 98%

Determination of Water Activity in Ammonium Sulfate and Sulfuric Acid Mixtures Using Levitated Single Particles

Kim

Pun

Chan

et al. 1994

Aerosol Science and Technology

Self Cite

View full text Add to dashboard Cite

Water activities of ammonium sulfate-sulfuric acid termiued relative to the known properties at RH about mixtures with ammonium to sulfate molar ratios be-0.75-0.90. The data were compared with other meatween 0 and 2 were measured by a spherical void surements and the estimates from the Zdanovskiielectrodynamic levitator at relative humidities (RH) of Stokes-Robinson (ZSR) method and SCAPE, a newly 0.18-0.90. Since the composition of the solid particles developed gas-particle equilibrium model, and generis subject to uncertainty, solution properties were deally were found to be in good agreement.

show abstract

Section: Resultsmentioning

confidence: 98%

Determination of Water Activity in Ammonium Sulfate and Sulfuric Acid Mixtures Using Levitated Single Particles

Kim

Pun

Chan

et al. 1994

Aerosol Science and Technology

Self Cite

View full text Add to dashboard Cite

show abstract

“…[69] STEM-2K3 employs the SAPRC-99 [Carter, 2000] gaseous mechanism, aerosol thermodynamics module SCAPE II (Simulating Composition of Atmospheric Particles at Equilibrium) [Kim et al, 1993a[Kim et al, , 1993bKim and Seinfeld, 1995] and NCAR Tropospheric Ultraviolet-Visible (TUV) radiation model [Madronich and Flocke, 1999]. In this experiment, the STEM-2K3 model included aerosols in four size bins (in diameter): 0.1-0.3 mm, 0.3-1.0 mm, 1.0-2.5 mm, and 2.5-10 mm [Tang et al, 2004].…”

Section: A4 University Of Iowa Stem-2k3 Modelmentioning

confidence: 99%

An evaluation of real‐time air quality forecasts and their urban emissions over eastern Texas during the summer of 2006 Second Texas Air Quality Study field study

et al. 2009

View full text Add to dashboard Cite

[1] Forecasts of ozone (O 3 ) and particulate matter (diameter less than 2.5 mm, PM 2.5 ) from seven air quality forecast models (AQFMs) are statistically evaluated against observations collected during August and September of 2006 (49 days) through the Aerometric Information Retrieval Now (AIRNow) network throughout eastern Texas and adjoining states. Ensemble O 3 and PM 2.5 forecasts created by combining the seven separate forecasts with equal weighting, and simple bias-corrected forecasts, are also evaluated in terms of standard statistical measures, threshold statistics, and variance analysis. For O 3 the models and ensemble generally show statistical skill relative to persistence for the entire region, but fail to predict high-O 3 events in the Houston region. For PM 2.5 , none of the models, or ensemble, shows statistical skill, and all but one model have significant low bias. Comprehensive comparisons with the full suite of chemical and aerosol measurements collected aboard the NOAA WP-3 aircraft during the summer 2006 Second Texas Air Quality Study and the Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS II/GoMACCS) field study are performed to help diagnose sources of model bias at the surface. Aircraft flights specifically designed for sampling of Houston and Dallas urban plumes are used to determine model and observed upwind or background biases, and downwind excess concentrations that are used to infer relative emission rates. Relative emissions from the U.S. Environmental Protection Agency 1999 National Emission Inventory (NEI-99) version 3 emissions inventory (used in two of the model forecasts) are evaluated on the basis of comparisons between observed and model concentration difference ratios. Model comparisons demonstrate that concentration difference ratios yield a reasonably accurate measure (within 25%) of relative input emissions. Boundary layer height and wind data are combined with the observed up-wind and downwind concentration differences to estimate absolute emissions. When the NEI-99 inventory is modified to include observed NO y emissions from continuous monitors and expected NO x decreases from mobile sources between 1999 and 2006, good agreement is found with those derived from the observations for both Houston and Dallas. However, the emission inventories consistently overpredict the ratio of CO to NO y . The ratios of ethylene and aromatics to NO y are reasonably consistent with observations over Dallas, but are significantly underpredicted for Houston.

show abstract

“…The most abundant ionic species were sulfate and ammonium, with lesser amounts of nitrate, and even smaller amounts of sodium and chloride. The aerosol equilibrium model SEQUILIB (Kim et al, 1993b, c) provides a method for translating ionic concentrations into those of the most thermodynamically stable set of chemical compounds likely to be present in an internally mixed aerosol. The ionic and elemental analyses are consistent with the primary inorganic chemical constituents being (NH 4 ) 2 SO 4 , (NH 4 )HSO 4 , NH 4 NO 3 , Na 2 SO 4 , NH 4 Cl, silicates, aluminosilicates, and other mineral species represented by other metal oxides, in addition to organic (OC) and elemental carbon (EC).…”

Section: Aerosol Chemical Compositionmentioning

confidence: 99%

Airborne measurements of aerosol extinction in the lower and middle troposphere over Wyoming, USA

Han

Montague

Snider

2003

Atmospheric Environment

View full text Add to dashboard Cite

Particle size distributions, and scattering and absorption coefficients were measured over the Green River basin of Wyoming during the Southwest Wyoming Visibility Study (SWYVIS) in February and March 1996. Eleven flights were carried out, using the Wyoming King Air research aircraft. In the least polluted regions of the planetary boundary layer, particle number densities detected in the diameter range 0.13-3.0 mm were o100 cm À3 . Aloft, in the stable air of the free troposphere, they were generally even lower, often falling to a few tens of particles per cm 3 . Analyses of bulk aerosol filter samples showed that organic carbonaceous material was the dominant chemical component, with sulfate and refractory species being the largest inorganic components. Combining the filter data with separately measured black carbon mass loading values allowed refractive indices for the aerosol to be calculated, so that PCASP measured size distributions could be revised. Characterizing size parameters were obtained by fitting particle populations to bimodal lognormal distributions. Particle size distributions were somewhat broader at higher altitudes so that larger particles made greater contributions to extinction. Optical closure was attempted by comparing scattering and total extinctions computed by Mie theory with the corresponding values derived from the observations. While the calculated and measured single scattering albedo average values were in reasonably good agreement, even though individual pairs of values sometimes differed significantly, computed scattering coefficients often exceeded those derived from the measurements, by an average of 60%. Reasons for this discrepancy are explored, including the possible modification of the size distribution by partial or total volatilization of particles within the nephelometer and its inlet. r

show abstract

Atmospheric Gas-Aerosol Equilibrium I. Thermodynamic Model

Cited by 345 publications

References 52 publications

Determination of Water Activity in Ammonium Sulfate and Sulfuric Acid Mixtures Using Levitated Single Particles

Determination of Water Activity in Ammonium Sulfate and Sulfuric Acid Mixtures Using Levitated Single Particles

An evaluation of real‐time air quality forecasts and their urban emissions over eastern Texas during the summer of 2006 Second Texas Air Quality Study field study

Airborne measurements of aerosol extinction in the lower and middle troposphere over Wyoming, USA

Contact Info

Product

Resources

About