Is the size distribution of urban aerosols determined by thermodynamic equilibrium?

Moya, M.; Pandis, Spyros Ν.; Jacobson, Mark Z.

doi:10.1016/s1352-2310(01)00549-0

Cited by 82 publications

(51 citation statements)

References 36 publications

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“…When Ca 2+ , K 2+ and Mg 2+ are treated as insoluble (unreactive), ISORROPIA-II predicts higher, on average, concentrations of ammonium compared to both the equivalent-Na and explicit treatment, since more sulfate is available to bind with ammonium, and thus the error and bias between predicted and observed ammonium increases for the insoluble approach (Table 5). For particulate nitrate, NME, NMB, MAGE and MB are the lowest when crustals (Moya et al, 2002;Jacobson, 1999). In the current dataset, aerosol nitrate is present in the form of ammonium nitrate (due to ammonia-rich environment) and thus replacing crustals with sodium is expected to have a minor effect on predicted nitrate response, primarily from differences in predicted water uptake (Table 5).…”

Section: Importance Of Explicitly Treating Crustal Speciesmentioning

confidence: 95%

“…Ansari and Pandis (2000) studied the impact of assuming a deliquescent vs. metastable path on the partitioning of nitrate in Southern California; when nitrate concentrations were low (<8 µg m −3 ), the considerations of both branches of aerosol behavior is essential, while no significant difference between stable and metastable predictions was found for high (>8 µg m −3 ) aerosol nitrate concentrations. Moya et al (2002) showed that the assumption of metastable state for sub-micrometer particles may introduce large errors when RH<60%, highlighting the importance of deliquescence predictions at low RH.…”

Section: Introductionmentioning

confidence: 99%

“…If measurements are slow, significant variations in T , RH and aerosol precursor concentrations may occur during sampling which cannot be accounted for in equilibrium calculations. Additionally, the consideration of crustal material in predicting the partitioning of nitrate and ammonium, especially in areas where dust comprises a significant portion of total PM, can affect the aerosol thermodynamics and improve model prediction skill (Ansari and Pandis, 1999;Moya et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

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Thermodynamic characterization of Mexico City aerosol during MILAGRO 2006

et al. 2009

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Abstract. Fast measurements of aerosol and gas-phase constituents coupled with the ISORROPIA-II thermodynamic equilibrium model are used to study the partitioning of semivolatile inorganic species and phase state of Mexico City aerosol sampled at the T1 site during the MILAGRO 2006 campaign. Overall, predicted semivolatile partitioning agrees well with measurements. PM 2.5 is insensitive to changes in ammonia but is to acidic semivolatile species. For particle sizes up to 1µm diameter, semi-volatile partitioning requires 15-30 min to equilibrate; longer time is typically required during the night and early morning hours. Aerosol and gas-phase speciation always exhibits substantial temporal variability, so that aerosol composition measurements (bulk or size-resolved) obtained over large integration periods are not reflective of its true state. When the aerosol sulfate-to-nitrate molar ratio is less than unity, predictions improve substantially if the aerosol is assumed to follow the deliquescent phase diagram. Treating crustal species as "equivalent sodium" (rather than explicitly) in the thermodynamic equilibrium calculations introduces important biases in predicted aerosol water uptake, nitrate and ammonium; neglecting crustals further increases errors dramatiCorrespondence to: A. Nenes (athanasios.nenes@gatech.edu) cally. This suggests that explicitly considering crustals in the thermodynamic calculations is required to accurately predict the partitioning and phase state of aerosols.

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Section: Importance Of Explicitly Treating Crustal Speciesmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermodynamic characterization of Mexico City aerosol during MILAGRO 2006

et al. 2009

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“…Resulting data have been utilized widely to validate air quality models (25)(26)(27) (28). In addition, the August 27-28, 1987 episode is statistically within the top 10% of severe ozone-forming meteorological conditions.…”

Section: Air Qualitymentioning

confidence: 99%

Determining Air Quality and Greenhouse Gas Impacts of Hydrogen Infrastructure and Fuel Cell Vehicles

Stephens-Romero

Carreras-Sospedra

Brouwer

et al. 2009

Environ. Sci. Technol.

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Adoption of hydrogen infrastructure and hydrogen fuel cell vehicles (HFCVs) to replace gasoline internal combustion engine (ICE) vehicles has been proposed as a strategy to reduce criteria pollutant and greenhouse gas (GHG) emissions from the transportation sector and transition to fuel independence. However, it is uncertain (1) to what degree the reduction in criteria pollutants will impact urban air quality, and (2) how the reductions in pollutant emissions and concomitant urban air quality impacts compare to ultralow emission gasoline-powered vehicles projected for a future year (e.g., 2060). To address these questions, the present study introduces a "spatially and temporally resolved energy and environment tool" (STREET) to characterize the pollutant and GHG emissions associated with a comprehensive hydrogen supply infrastructure and HFCVs at a high level of geographic and temporal resolution. To demonstrate the utility of STREET, two spatially and temporally resolved scenarios for hydrogen infrastructure are evaluated in a prototypical urban airshed (the South Coast Air Basin of California) using geographic information systems (GIS) data. The well-to-wheels (WTW) GHG emissions are quantified and the air quality is established using a detailed atmospheric chemistry and transport model followed by a comparison to a future gasoline scenario comprised of advanced ICE vehicles. One hydrogen scenario includes more renewable primary energy sources for hydrogen generation and the other includes more fossil fuel sources. The two scenarios encompass a variety of hydrogen generation, distribution, and fueling strategies. GHG emissions reductions range from 61 to 68% for both hydrogen scenarios in parallel with substantial improvements in urban air quality (e.g., reductions of 10 ppb in peak 8-h-averaged ozone and 6 µg/m 3 in 24-h-averaged particulate matter concentrations, particularly in regions of the airshed where concentrations are highest for the gasoline scenario).

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“…The study collected an extensive set of meteorological and air quality data that has been used widely to validate air quality models (Meng et al, 1998;Griffin et al, 2002a,b;Pun et al, 2002;Moya et al, 2002). Zeldin et al (1990) indicated that August 28, 1987 is representative of the meteorological conditions in the SoCAB, which makes it suitable for modeling an air quality episode.…”

Section: Meteorological Conditionsmentioning

confidence: 99%

Central power generation versus distributed generation – An air quality assessment in the South Coast Air Basin of California

Carreras-Sospedra

Vutukuru

Brouwer

et al. 2010

Atmospheric Environment

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a b s t r a c tThis study assesses the air quality impacts of central power generation and compares them with the impacts of distributed generation (DG). The central power plant emissions factors used are from a newly installed combined cycle gas turbine system. Because location of power plants is a key parameter affecting air quality impacts, this study considers three potential locations for the installation of central power plants. Air quality impacts are evaluated for the South Coast Air Basin of California, in the year 2010, using a three-dimensional air quality model. Results are compared to air quality impacts from two potential DG scenarios to meet the same power demand as that of the central power plant case.Even though emissions from central generation are lower than emissions from the DG technology mix considered herein, central generation concentrates emissions in a small area, whereas DG spreads emissions throughout a larger cross-section of the air basin. As a result, air quality impacts from central generation are more significant than those from DG. The study also shows that assessment of air quality impacts from distributed and central generation should not only consider emissions levels, but also the spatial and temporal distribution of emissions and the air quality that results from atmospheric chemistry and transport e highly non-linear processes.Finally, analysis of population exposure to ozone and PM 2.5 shows that central generation located in coastal areas upwind from populated areas would cause the highest population exposure and even though emissions from central generation are considerably lower than DG emissions spread throughout the basin, results show that central generation causes a higher pollutant exposure than DG.

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Is the size distribution of urban aerosols determined by thermodynamic equilibrium?

Cited by 82 publications

References 36 publications

Thermodynamic characterization of Mexico City aerosol during MILAGRO 2006

Thermodynamic characterization of Mexico City aerosol during MILAGRO 2006

Determining Air Quality and Greenhouse Gas Impacts of Hydrogen Infrastructure and Fuel Cell Vehicles

Central power generation versus distributed generation – An air quality assessment in the South Coast Air Basin of California

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