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

Croes, Bart; Holmes, John R.; Lloyd, A. C.

doi:10.1080/10473289.1992.10467017

Cited by 12 publications

(7 citation statements)

References 9 publications

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“…* With motor vehicle NMOG and CO exhaust emissions doubled. 8 Summation of the population x concentration x hours for any modeling grid that experienced an ozone concentration greater than the prescribed vaiue.…”

Section: Resultsmentioning

confidence: 99%

“…A useful statistic for judging how closely the RAF leads to an equal ozone impact is the "null test," defined as the concentration increment due to the alternative fuel, normalized relative to that of the conventional fuel: 11.1 8.8 8 Results for third day of simulation. " With motor vehicle NMOG and CO exhaust emissions doubled.…”

Section: Resultsmentioning

confidence: 99%

“…The null test results of Smylie et al 7 for a different Los Angeles episode and the Urban Airshed Model (UAM) found biases that favored CNG and M85 over conventional gasoline. An extension of the UAM study by the Auto/Oil Air Quality Improvement Research Program (AQIRP) presented at the 1991 Reactivity Conference 8 showed biases favoring a gasoline reformulated with lower amounts of alkenes and aromatic hydrocarbons and a lower 90 percent boiling point. Much of this bias was removed if the MOIR scale was used to calculate the RAF.…”

Section: Introductionmentioning

confidence: 99%

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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: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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“…Smylie et al (1990) used the UAM with the CB4 mechanism to simulate null tests in a different Los Angeles episode, and found that MIR null test substitutions of M85 or CNG caused ozone to increase by up to 30%. An extension of this study for AQIRP presented at the 1991 Reactivity Conference (Croes et al, 1992) showed that UAM simulations of MIR null test substitutions of a reformulated gasoline with lower aromatics and higher alkenes also resulted in increased ozone. However, in all cases, the chemical mechanisms employed was different than that used to calculate the RAFs.…”

Section: % Sub Subst (Irratio)mentioning

confidence: 82%

Atmospheric Process Evaluation of Mobile Source Emissions

Author¹

1995

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“…Ορίζεται ως η µεταβολή της συγκέντρωσης όζοντος ανά µονάδα προστιθέµενης, σε ένα συγκεκριµένο µίγµα NO X -VOC, οργανικής ένωσης (εκφρασµένη σε άτοµα C) [Carter και Atkinson, 1987;]. [Croes et al, 1992].…”

Section: ∆ραστικότητα των οργανικών ενώσεωνunclassified

Μελέτη Της Επίδρασης Των Παραγόντων Που Ευνοούν Τη Δημιουργία Και Συσσώρευση Όζοντος Στην Περιοχή Της Αττικής Με Τη Μέθοδο Της Αριθμητικής Προσομοίωσης

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

Cited by 12 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

Atmospheric Process Evaluation of Mobile Source Emissions

Μελέτη Της Επίδρασης Των Παραγόντων Που Ευνοούν Τη Δημιουργία Και Συσσώρευση Όζοντος Στην Περιοχή Της Αττικής Με Τη Μέθοδο Της Αριθμητικής Προσομοίωσης

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