Ion formation in hydrocarbon flames

Blades, Arthur T.

doi:10.1139/v76-413

Cited by 40 publications

(27 citation statements)

References 8 publications

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“…The slope of the straight line obtained from the five standard samples provided a FID response factor in ppbC per peak area counts which was used for all GC peaks. The utilization of a single per carbon response factor for all GC peaks appears to be valid, particularly for hydrocarbon‐type VOCs [ Leveque , 1967; Ackman , 1968; Blades , 1976; Apel et al , 1994], and is a typical practice for GC/FID applications. The accuracy provided with the NIST‐SRM standard applies directly to the propane results in canister samples and it is expected that the accuracy of the other hydrocarbon‐type VOCs to be reasonably similar.…”

Section: Methodsmentioning

confidence: 99%

Ozone production efficiency and NO_x depletion in an urban plume: Interpretation of field observations and implications for evaluating O₃‐NO_x‐VOC sensitivity

et al. 2003

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[1] Ozone production efficiency (OPE) can be defined as the number of ozone (O 3 ) molecules photochemically produced by a molecule of NO x (NO + NO 2 ) before it is lost from the NO x À O 3 cycle. Here we consider observational and modeling techniques to evaluate various operational definitions of OPEs using aircraft and surface measurements taken as part of the 1999 Southern Oxidant Study field campaign in Nashville, Tennessee. A key tool in our analysis is a Lagrangian box model, which is used to quantitatively describe the effects of emissions, dilution, dry deposition, and photochemistry in an urban air parcel as it was advected downwind. After evaluating the model using the observed downwind concentrations of several key species, we show that the modeled NO x oxidation and O 3 production rates as well as the associated instantaneous and cumulative OPEs depend on the time of day and the photochemical age of the air parcel. The observationbased OPEs are found to be consistent with the modeled values with the expected biases. A model sensitivity study suggests that downwind O 3 concentrations in the Nashville plume are more sensitive to NO x emissions than anthropogenic VOC emissions. Because the OPE exhibits a nonlinear dependence on emissions and meteorological effects, it would be difficult to rely only on observations to map out the nonlinear response of O 3 to a wide span of NO x and VOC emission changes. Properly constrained and well-evaluated models using a variety of observations are therefore necessary to reliably predict O 3 -NO x -VOC sensitivity for designing effective O 3 control strategies.

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Section: Methodsmentioning

confidence: 99%

Ozone production efficiency and NO_x depletion in an urban plume: Interpretation of field observations and implications for evaluating O₃‐NO_x‐VOC sensitivity

et al. 2003

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“…By these methods, the selected standards used in this study have been shown to be stable since their preparation and our in-house prepared standards compare favorably (±3%) with the NIST prepared standards giving us additional confidence in our calibration. When no specific corresponding NIST standards were available, response factors were referenced to NIST SRM propane, and proportional responses with carbon number were assumed [Leveque, 1967;Ackman, 1968;Blades, 1976;Apel et al, 1995]. The calibration accuracy for the compounds quantified in this way, under the FID conditions employed, is estimated to be ±4% [Apel et al, 1995[Apel et al, , 1999.…”

Section: Ncar-nomhice Methodsmentioning

confidence: 99%

“…Five distinct mixing ratios, achieved by dynamically diluting the SRM propane, were used to prepare the calibration curve. The slope determined from the curve is the response factor in area counts per parts per billion carbon (ppbC) and was used to determine ppbC mixing ratios for all compound peaks; ppbC mixing ratios were subsequently converted to ppbv units [Leveque, 1967;Ackman, 1968;Blades, 1976;Apel et al, 1995]. The precison, defined as the relative standard deviation of the lowest propane mixing ratio, i.e., 2.5 ppbC, was ±1.9%.…”

Section: Epa Methodsmentioning

confidence: 99%

“…Others use secondary standards obtained from a commercial source, while still others purchase gravimetric standards from a National Laboratory such as NIST. Some laboratories rely on the near-proportional response to carbon observed for most NMHCs in FIDs and reference the results to a single NMHC standard [Leveque, 1967;Ackman, 1968;Blades, 1976;Apel et al, 1995]. Other laboratories use a standard for each compound that they wish to analyze, and calibrate their instruments accordingly.…”

Section: Analysis Methods For Nmhcsmentioning

confidence: 99%

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Nonmethane Hydrocarbon Intercomparison Experiment (NOMHICE): Task 4, ambient air

et al. 2003

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[1] The Nonmethane Hydrocarbon Intercomparison Experiment (NOMHICE) was designed to assess the accuracy and comparability of nonmethane hydrocarbon (NMHC) measurements from research groups around the globe. This is being accomplished by conducting a series of intercomparisons, called Tasks, of prepared mixtures or collected ambient air. This paper presents results for an ambient air challenge sample as part of the fourth NOMHICE installment (Task 4). Twenty-three laboratories participated in Task 4, and 30 overall analytical results are compared. The air sample provided a wide dynamic range of mixing ratios (parts per trillion by volume (pptv) to parts per billion by volume (ppbv)) as well as large number of compounds (>100). Coelutions of NMHCs with other volatile organic compounds (VOCs) such as oxygenated VOCs are shown to make the analysis of whole air samples more challenging than for prepared standard mixtures. Individual canisters containing the air sample were prepared and analyzed by the NOMHICE group at the National Center for Atmospheric Research (NCAR-NOMHICE), sent to participants for analysis, and reanalyzed upon return to NCAR-NOMHICE. The mixing ratio of propylene increased by 10% (14 pptv) in the canisters with time, and some of the less volatile compounds decreased in the canisters with time; however, the majority of the compounds were stable throughout the experiment. Participants were asked to identify and quantify as many compounds as possible with their analytical techniques and to submit their results to NCAR-NOMHICE scientists. Fiftyfour compounds were chosen for the intercomparison. Eight hundred eighty-three measurements were compared overall; the average of the mean ratios of the participants' results to NCAR-NOMHICE results was 1.03. The participants' results were combined and averaged for each individual NMHC measured and compared to the reference results; thirty-three of the 54 compounds agreed to within ±20% of the reference results. Individual analyses from participant laboratories were compared and ranked with respect to agreement with the reference values; the ranking was reconciled with the analytical procedures employed for each analysis. From this, recommendations were derived for preferred analytical techniques and practice. Recommendations include but are not limited to the following: (1) National Institute of Standards and Technology (NIST) standards or NIST-traceable standards should be used and, for mass spectrometric analyses, multicomponent NIST-traceable standards should be used; (2) if solid adsorbents are used for preconcentrating NMHCs, extensive tests should be performed to test for artifact formation and compound losses; and (3) for whole air sampling in canisters, subsequent analyses should be performed as soon as is reasonably possible to avoid the potential for compositional changes.

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“…The exception to this for previously studied compounds is acetylene, which has an anomalously high response. 17 To further investigate the assumption of equal per carbon response, NCAR-HCMTS ran a series of experiments with an NIST-prepared, 16-component, gravimetric standard and compared the relative per carbon response for each compound. Figure 1 is a plot of the relative response per carbon number, with respect to n-butane, for the 16 compounds in the NIST standard.…”

Section: Research Conducted Prior To the Atlanta Intensivementioning

confidence: 99%

Hydrocarbon Measurements During the 1992 Southern Oxidants Study Atlanta Intensive: Protocol and Quality Assurance

Apel

Calvert

Zika

et al. 1995

Journal of the Air & Waste Management Association

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A major component of the Southern Oxidants Study (SOS) 1992 Atlanta Intensive was the measurement of atmospheric nonmethane hydrocarbons. Ambient air samples were collected and analyzed by a network of strategically located automated gas chromatography (GC) systems (field systems). In addition, an extensive canister sampling network was deployed. Combined, more than 3000 chromatograms were IMPLICATIONS Accurate measurements of ozone precursors are required to understand the process and extent of ozone formation in rural and urban areas. Nonmethane hydrocarbons (NMHCs) have been identified as important ozone precursors. Recently, automated gas chromatographic (GC) systems have been developed for both intensive field measurements and continuous monitoring of these species. Identification and quantification of NMHCs is difficult because of the large number present and the wide molecular weight range encountered in typical air samples. This article describes the efforts of a group of scientists to make high-quality automated GC measurements of targeted NMHCs during the Southern Oxidants Study (SOS) 1992 Atlanta Intensive. This work indicates the importance of proper gas standards, a well-thought-out protocol, and periodic evaluations of deployed measurement systems.recorded. The SOS science team targeted for quantitative analysis 56 compounds which may be substantial contributors to ozone formation or used as air mass tracers. A quality assurance program was instituted to ensure that good measurements were being made throughout the network for each target compound. Common, high-quality standards were used throughout the network. The performance of individual field systems was evaluated during the intensive through the analysis of challenge mixtures. This methodology helped to identify and correct analytical problems as they arose.

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Ion formation in hydrocarbon flames

Cited by 40 publications

References 8 publications

Ozone production efficiency and NO_x depletion in an urban plume: Interpretation of field observations and implications for evaluating O₃‐NO_x‐VOC sensitivity

Ozone production efficiency and NO_x depletion in an urban plume: Interpretation of field observations and implications for evaluating O₃‐NO_x‐VOC sensitivity

Nonmethane Hydrocarbon Intercomparison Experiment (NOMHICE): Task 4, ambient air

Hydrocarbon Measurements During the 1992 Southern Oxidants Study Atlanta Intensive: Protocol and Quality Assurance

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Ion formation in hydrocarbon flames

Cited by 40 publications

References 8 publications

Ozone production efficiency and NOx depletion in an urban plume: Interpretation of field observations and implications for evaluating O3‐NOx‐VOC sensitivity

Ozone production efficiency and NOx depletion in an urban plume: Interpretation of field observations and implications for evaluating O3‐NOx‐VOC sensitivity

Nonmethane Hydrocarbon Intercomparison Experiment (NOMHICE): Task 4, ambient air

Hydrocarbon Measurements During the 1992 Southern Oxidants Study Atlanta Intensive: Protocol and Quality Assurance

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Product

Resources

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Ozone production efficiency and NO_x depletion in an urban plume: Interpretation of field observations and implications for evaluating O₃‐NO_x‐VOC sensitivity

Ozone production efficiency and NO_x depletion in an urban plume: Interpretation of field observations and implications for evaluating O₃‐NO_x‐VOC sensitivity