Dependence of ozone production on NO and hydrocarbons in the troposphere

Kleinman, Lawrence I.; Daum, P. H.; Lee, Jai H.; Lee, Yin-Nan; Nunnermacker, L. J.; Springston, Stephen; Newman, L.; Weinstein-Lloyd, J.; Sillman, Sanford

doi:10.1029/97gl02279

Cited by 161 publications

(175 citation statements)

References 13 publications

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“…Here we define VOC-limited as where the ratio of L N (loss of radicals from reactions with NO and NO 2 ) to Q (the sum of all radical sinks) is more than 0.5 (Kleinman et al, 1997;Wiedinmyer et al, 2006). NO x -limited is defined as where L N /Q is less than 0.5 (Kleinman et al, 1997;Wiedinmyer et al, 2006). To ensure that each regime includes the same grid cells in CheT, CheT2, AQUM and LLSF, L N /Q values from CheT were used in all cases.…”

Section: Defining Distinct O X Production Regimesmentioning

confidence: 99%

Influence of isoprene chemical mechanism on modelled changes in tropospheric ozone due to climate and land use over the 21st century

et al. 2015

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Abstract. Isoprene is a precursor to tropospheric ozone, a key pollutant and greenhouse gas. Anthropogenic activity over the coming century is likely to cause large changes in atmospheric CO 2 levels, climate and land use, all of which will alter the global vegetation distribution leading to changes in isoprene emissions. Previous studies have used global chemistry-climate models to assess how possible changes in climate and land use could affect isoprene emissions and hence tropospheric ozone. The chemistry of isoprene oxidation, which can alter the concentration of ozone, is highly complex, therefore it must be parameterised in these models. In this work, we compare the effect of four different reduced isoprene chemical mechanisms, all currently used in Earth system models, on tropospheric ozone. Using a box model we compare ozone in these reduced schemes to that in a more explicit scheme (the Master Chemical Mechanism) over a range of NO x and isoprene emissions, through the use of O 3 isopleths. We find that there is some variability, especially at high isoprene emissions, caused by differences in isoprene-derived NO x reservoir species. A global model is then used to examine how the different reduced schemes respond to potential future changes in climate, isoprene emissions, anthropogenic emissions and land use change. We find that, particularly in isoprene-rich regions, the response of the schemes varies considerably. The wide-ranging response is due to differences in the model descriptions of the peroxy radical chemistry, particularly their relative rates of reaction towards NO, leading to ozone formation, or HO 2 , leading to termination. Also important is the yield of isoprene nitrates and peroxyacyl nitrate precursors from isoprene oxidation. Those schemes that produce less of these NO x reservoir species, tend to produce more ozone locally and less away from the source region. We also note changes in other key oxidants such as NO 3 and OH (due to the inclusion of additional isoprene-derived HO x recycling pathways). These have implications for secondary organic aerosol formation, as does the inclusion of an epoxide formation pathway in one of the mechanisms. By combining the emissions and O 3 data from all of the global model integrations, we are able to construct isopleth plots comparable to those from the box model analysis. We find that the global and box model isopleths show good qualitative agreement, suggesting that comparing chemical mechanisms with a box model in this framework is a useful tool for assessing mechanistic performance in complex global models. We conclude that as the choice of reduced isoprene mechanism may alter both the magnitude and sign of the ozone response, how isoprene chemistry is parameterised in perturbation experiments such as these is a crucially important consideration. More measurements and laboratory studies are needed to validate these reduced mechanisms especially under high-volatile-organiccompound, low-NO x conditions.

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Section: Defining Distinct O X Production Regimesmentioning

confidence: 99%

Influence of isoprene chemical mechanism on modelled changes in tropospheric ozone due to climate and land use over the 21st century

et al. 2015

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“…Though not shown here, the high PAN/HNO 3 may also affect the L n /Q approach developed by Kleinman et al (1997Kleinman et al ( , 2005 to evaluate how instantaneous production of O 3 varies with NO x and VOC. The L n /Q is based on the rate of removal of NO x (L n ), and the relative rate of production of odd hydrogen radicals (Q), assuming that formation of HNO 3 is the dominant radical sink.…”

Section: Indicators For No X -Voc Sensitivitymentioning

confidence: 99%

“…Peroxides are produced by the reactions The contrast between NO x -sensitive and VOC-sensitive photochemistry is closely related to the relative rates of formation of peroxides (R1a and b) and nitric acid (R2), both of which are sinks for odd hydrogen radicals and thus indirectly affect the rate of ozone formation (Sillman, 1995;Kleinman et al, 1997;Kleinman, 2005;Thornton et al, 2002). Consequently, a high value for the ratio H 2 O 2 /HNO 3 is associated with NO x -sensitive photochemistry and a low value is associated with VOC-sensitive photochemistry.…”

Section: Introductionmentioning

confidence: 99%

Reactive nitrogen in Mexico City and its relation to ozone-precursor sensitivity: results from photochemical models

Sillman

West

2009

Atmos. Chem. Phys.

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Abstract.We use results of a 3-D photochemistry/transport model for ozone formation in Mexico City during events in 1997 to investigate ambient concentrations of reactive nitrogen in relation to ozone-precursor sensitivity. Previous results from other locations suggest that ratios such as O 3 /NO y and H 2 O 2 /HNO 3 might provide measurement-based indicators for NO x -sensitive or VOC-sensitive conditions. Mexico City presents a different environment due to its high concentrations of VOC and high level of pollutants in general. The model predicts a correlation between PAN and O 3 with relatively high PAN/O 3 (0.07), which is still lower than measured values. The model PAN is comparable with results from a model for Paris but much higher than were found in Nashville in both models and measurements. The difference is due in part to the lower temperature in Mexico City relative to Nashville. Model HNO 3 in Mexico City is unusually low for an urban area and PAN/HNO 3 is very high, probably due to the high ratio of reactivity-weighted VOC to NO x . The model predicts that VOC-sensitive chemistry in Mexico is associated with high NO x , NO y and NO x /NO y and with low O 3 /NO y and H 2 O 2 /HNO 3 , suggesting that these indicators work well for Mexico City. The relation between ozone-precursor sensitivity and either O 3 /NO z or O 3 /HNO 3 is more ambiguous. VOC-sensitive conditions are associated with higher O 3 /HNO 3 than would be found in NO x -sensitive conditions, but model O 3 /HNO 3 associated with both NO xsensitive and VOC-sensitive chemistry is higher in Mexico than in other cities. The model predicts a mixed pattern of ozone-precursor sensitivity in Mexico City, with VOCsensitive conditions in the morning and NO x -sensitive in the afternoon, in contrast to results from other models for more recent events that predicted strongly VOC-sensitive conditions throughout the day. The difference in predicted ozoneCorrespondence to: S. Sillman (sillman@umich.edu) precursor sensitivity is most likely due to different emission rates and to changes in emissions over time. The model with mixed sensitivity predicts much lower ambient NO x and NO x /NO y than the strongly VOC-sensitive model.

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“…Calculations were performed with an observation driven photochemical box model and used steady state approximations as described by Kleinman et al [1997]. The model consists of the kinetic rate expressions for species not constrained to their observed values, i.e., OH, HO2, organic peroxy radicals, and NO2.…”

Section: Model Calculationsmentioning

confidence: 99%

Analysis of the processing of Nashville urban emissions on July 3 and July 18, 1995

Daum¹,

Kleinman²,

Imre³

et al. 2000

J. Geophys. Res.

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Abstract. This paper analyzes data obtained on July 3 and 18, 1995, during the summer 1995 Southern Oxidant Study (SOS) field campaign. In a previous paper [Nunnermacker et al., 1998] we analyzed measurements of key species that contribute to formation of O3 in the Nashville urban plume and presented a semiquantitative picture of O3 production in the plume from the point of emission to locations where no net O3 was being formed. In this paper we use a box model constrained by observed concentrations of stable species to obtain a detailed mechanistic description of the instantaneous processing of urban emissions at various times in the chemical evolution of the urban plume. Instantaneous ozone production rates and efficiencies with respect to NOx and to primary radical production are examined. At high NOx concentrations in the fresh urban plume the O3 production rate was found to be directly proportional to the hydrocarbon to NOx reactivity ratio. At lower NOx concentrations, corresponding to the mature urban plume and the background atmosphere, the O3 production rate was found to be directly proportional to the NOx concentration and independent of the hydrocarbon reactivity. NOx was found to be most efficiently used for ozone production at low NOx concentrations. In contrast, the efficiency with which the system uses primary radicals was found to be very low at low NOx concentrations and to peak at a NOx concentration of approximately 4 ppbv. A sensitivity study of the instantaneous O3 production rates to changes in NOx or hydrocarbon concentrations showed that the instantaneous 03 production rate at the center of the urban plume, when half of the urban NOx emissions had been processed, is hydrocarbon sensitive. However, 03 production becomes NOx sensitive as the plume matures.

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Dependence of ozone production on NO and hydrocarbons in the troposphere

Cited by 161 publications

References 13 publications

Influence of isoprene chemical mechanism on modelled changes in tropospheric ozone due to climate and land use over the 21st century

Influence of isoprene chemical mechanism on modelled changes in tropospheric ozone due to climate and land use over the 21st century

Reactive nitrogen in Mexico City and its relation to ozone-precursor sensitivity: results from photochemical models

Analysis of the processing of Nashville urban emissions on July 3 and July 18, 1995

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