Airshed Calculation of the Sensitivity of Pollutant Formation to Organic Compound Classes and Oxygenates Associated with Alternative Fuels

McNair, Laurie A.; Russell, Armistead G.; Odman, M. Talat

doi:10.1080/10473289.1992.10466981

Cited by 21 publications

(26 citation statements)

References 9 publications

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“…One issue is whether this is an adequate representation of actual ozone episodes, usually extending over several days in California, whose severity is strongly dependent on meteorological conditions, and which operate over a wide range of NO X levels. McNair et al 2 addressed this issue by computing incremental reactivities with the, physically detailed Carnegie/California Institute of Technology (CIT) airshed model for a severe three-day stagnation episode in Los Angeles when the daily ozone maximum was limited by the availability of NO X , but with high NO X levels in the source areas. Because airshed models are formulated with condensed chemical mechanisms, incremental reactivities were derived for only 11 individual and "lumped" organic gases.…”

Section: Introductionmentioning

confidence: 99%

Airshed Model Evaluation of Reactivity Adjustment Factors Calculated with the Maximum Incremental Reactivity Scale for Transitional-Low Emission Vehicles

et al. 1994

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The California Air Resources Board recently adopted regulations for light-and medium-duty vehicles that require reductions in the ozone-forming potential or "reactivity," rather than the mass, of nonmethane organic gas (NMOG) emissions. The regulations allow sale of all alternatively fueled vehicles (AFVs) that meet NMOG exhaust emission standards equivalent in reactivity to those set for vehicles fueled with conventional gasoline. Reactivity adjustment factors (RAFs), the ratio of the reactivity (per gram) of the AFV exhaust to that of the conventionally fueled vehicle (CFV), are used to correct the stringent exhaust emission standards. Complete chemical speciation of the exhaust and conversion of each NMOG species to an appropriate mass of ozone using the maximum incremental reactivity (MIR) scale of Carter determines the RAF. The MIR approach defines reactivity where NMOG control is the most effective strategy in reducing ozone concentrations, and assumes it is not important to define reactivity at other conditions, i.e., where NO X is the limiting precursor.This study used the Carnegie/California Institute of Technology airshed model to evaluate whether the RAF-adjusted AFV emissions result in ozone impacts equivalent to those of CFV emissions. A matrix of two ozone episodes in the South Coast Air Basin (SoCAB) of California, two base emission inventories, and exhaust emissions from three alternative fuels that meet the first level of the low emission vehicle standards bounds the expected range of conditions. Although very good agreement was found previously for individual NMOG species, 2 this study noted deviations of up to ±15 percent from the equal ozone impacts for any vehicle/fuel combination required by the California regulations. These deviations appear to be attributable to differences in spatial and temporal patterns of emissions between vehicle fleets, rather than a problem with the MIR approach. The first formally adopted RAF, a value of 0.41 for 85 percent methanol/15 percent gasoline-fueled vehicles, includes a 10 percent increase based on the airshed modeling. The correction to the RAF is different for other fuels and may be different for air basins other than the SoCAB. ImplicationsStringent "low emission vehicle" regulations recently adopted by the California Air Resources Board to reduce ozone precursor emissions are "fuel neutral" in the sense that reactivity adjustment factors {RAFs) are used to relax the standards for fuel/vehicle combinations with exhaust emissions having a lower ozone-forrning potential {per unit mass) than those fueled with conventional gasoline. This study uses the Carnegie/California Institute of Technology airshed model for a range ot ozone episodes and base emission inventories to evaluate whether the RAFs for alternative fuels computed with the maximum incremental reactivity (MIR) scale lead to ozone impacts equal to those of conventional gasoline for the first level of the low emission vehicle standards. The RAFs need corrections of \ip to ...15 percent, dependin...

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Section: Introductionmentioning

confidence: 99%

Airshed Model Evaluation of Reactivity Adjustment Factors Calculated with the Maximum Incremental Reactivity Scale for Transitional-Low Emission Vehicles

et al. 1994

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“…While primary emissions of formaldehyde from methanol combustion leads to increased production of ozone, H20 2 , formic acid, and CO, depending upon the atmospheric levels of NO/ NO2, primary acetaidehyde from ethanol combustion leads to the formation of these same products, as well as PAN, acetic acid, and peracetic acid (Atkutsu et al, 1991;McNair et al, 1992). The observation of elevated levels of PAN has been used as an indicator for primary acetaidehyde emissions (Tanner et al, 1988;Popp et al" 1995;Gaffney et al, 1997).…”

Section: Alcohol Fuelsmentioning

confidence: 99%

Aerosol Absorption and Scattering Measurements: Field Measuremnets and Laboratory Characterizations.

Marley¹,

Gaffney²

2011

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A suite of instrumentation was deployed in MAX-Mex at site TO, located in the northern part of the Mexico City Metropolitan Area, (MCMA), for the characterization of the aerosol optical properties in the field. Measurements were made of the following aerosol properties: (1) aerosol absorption as a function of wavelength, measured at two minute intervals with a 7-wavelength Aethalometer (2) aerosol scattering as a function of wavelength, measured at one minute intervals with a 3-wavelength nephelometer; 3) aerosol scattering as a function of relative humidity (RH), measured at one minute intervals with 2 single-wavelength nephelometers operated under dry (10% RH) and wet (80% RH) conditions; and 4) collection of sizefractionated aerosol samples on quartz fiber filters at 12 hour intervals (day/night) for further laboratory characterization. Aerosol filter samples were also collected at site Tl (located north of MCMA) for comparison with those collected in the city center. Preliminary results from in situ measurements have indicated an enhanced UV absorption in the afternoon over that expected from black carbon (BC) aerosols alone. These results are directly applicable to both modeling of aerosol radiative forcing and satellite optical depth retrieval algorithms. Both of these applications assume that the aerosol absorption is due only to BC with a wavelength dependence of A, " whereas results obtained in MAX-Mex show that the aerosol wavelength exponent varies over Mexico City from -0.7 to -1.5.All of the data collected in the field from the measurement sets 1-3 have been made available to the ASP community via the MILAGRO data site housed at NCAR. The laboratory characterization of aerosol samples collected in the ASP MAX-Mex field study compared results from Mexico City to samples collected at other sites, including Chicago, Little Rock, and Mt. Bachelor, OR. The project focused on obtaining complete spectral characterization of aerosolsespecially their absorption characteristics as they relate to basic chemical functional groups. Particular attention was given to organics and from biogenic derived organic compounds. This included determinations of the UV-Visible-NIR characteristics of the aerosol absorption as reported as Angstrom Absorption Exponents. Correlation of these results with IR band observations of carboxylic acid, and carboxylate groups were conducted, along with past correlations with carbon isotopic data that indicated significant enhancements of UV-Visible absorption from biogenic aerosols (both biomass burning and secondary organic aerosols). Relationships to other ASP ProjectsThis project collaborated with a number of currently funded ASP projects including research being conducted by Dr. W. Patrick Arnott at the University of Nevada, Reno. Dr. Arnott made use of photoacoustic spectroscopy and light scattering at one or two wavelengths to determine SSA of the aerosol. Comparison of the aethalometer data as well as MAAP instrumentation yielded good to excellent agreement between the instruments...

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“…At issue is whether this is an adequate representation of actual ozone episodes, which tend to extend over several days in California, and whose severity is strongly dependent on meteorological conditions. McNair et al 15 addressed this issue by computing incremental reactivities with a physically detailed, three-dimensional airshed model for a severe, three-day stagnation episode in Los Angeles when the daily ozone maximum was limited by the availability of NO X . Because airshed models are formulated with condensed chemical mechanisms, incremental reactivities were derived for only eleven individual and "lumped" organic gases.…”

Section: Scientific Uncertaintiesmentioning

confidence: 99%

Reactivity-Based Hydrocarbon Controls: Scientific Issues and Potential Regulatory Applications

Croes

Holmes

Lloyd³

1992

Journal of the Air & Waste Management Association

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Airshed Calculation of the Sensitivity of Pollutant Formation to Organic Compound Classes and Oxygenates Associated with Alternative Fuels

Cited by 21 publications

References 9 publications

Airshed Model Evaluation of Reactivity Adjustment Factors Calculated with the Maximum Incremental Reactivity Scale for Transitional-Low Emission Vehicles

Airshed Model Evaluation of Reactivity Adjustment Factors Calculated with the Maximum Incremental Reactivity Scale for Transitional-Low Emission Vehicles

Aerosol Absorption and Scattering Measurements: Field Measuremnets and Laboratory Characterizations.

Reactivity-Based Hydrocarbon Controls: Scientific Issues and Potential Regulatory Applications

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