Verification of the Contribution of Vehicular Traffic to the Total NMVOC Emissions in Germany and the Importance of the NO3 Chemistry in the City Air

Kurtenbach, R.; Ackermann, R.; Becker, Karl‐Heinz; Geyer, Andreas; Gomes, Jewel A.; Lörzer, J. C.; Platt, U.; Wiesen, Peter

doi:10.1007/978-94-010-0399-5_16

Cited by 35 publications

(29 citation statements)

References 26 publications

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“…RCAT8.2 considers temporally varying anthropogenic emissions, predominately from traffic between 0.1 m and 1 m altitude, as well as biogenic emissions at the ground and between 1 m and 10 m altitude. Anthropogenic VOC (volatile organic compounds) and NO x emissions are linked in the model using emission ratios based on Kurtenbach et al (2001Kurtenbach et al ( , 2002. Surface uptake resulting in dry deposition and chemistry on aerosol and ground surfaces are included as well.…”

Section: Model Descriptionmentioning

confidence: 99%

Modeling of daytime HONO vertical gradients during SHARP 2009

et al. 2013

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Nitrous acid (HONO) acts as a major precursor of the hydroxyl radical (OH) in the urban atmospheric boundary layer in the morning and throughout the day. Despite its importance, HONO formation mechanisms are not yet completely understood. It is generally accepted that conversion of NO₂ on surfaces in the presence of water is responsible for the formation of HONO in the nocturnal boundary layer, although the type of surface on which the mechanism occurs is still under debate. Recent observations of higher than expected daytime HONO concentrations in both urban and rural areas indicate the presence of unknown daytime HONO source(s). Various formation pathways in the gas phase, and on aerosol and ground surfaces have been proposed to explain the presence of daytime HONO. However, it is unclear which mechanism dominates and, in the cases of heterogeneous mechanisms, on which surfaces they occur.

Vertical concentration profiles of HONO and its precursors can help in identifying the dominant HONO formation pathways. In this study, daytime HONO and NO₂ vertical profiles, measured in three different height intervals (20–70, 70–130, and 130–300 m) in Houston, TX, during the 2009 Study of Houston Atmospheric Radical Precursors (SHARP) are analyzed using a one-dimensional (1-D) chemistry and transport model. Model results with various HONO formation pathways suggested in the literature are compared to the the daytime HONO and HONO/NO₂ ratios observed during SHARP. The best agreement of HONO and HONO/NO₂ ratios between model and observations is achieved by including both a photolytic source of HONO at the ground and on the aerosol. Model sensitivity studies show that the observed diurnal variations of the HONO/NO₂ ratio are not reproduced by the model if there is only a photolytic HONO source on aerosol or in the gas phase from NO₂^* + H₂O. Further analysis of the formation and loss pathways of HONO shows a vertical dependence of HONO chemistry during the day. Photolytic HONO formation at the ground is the major formation pathway in the lowest 20 m, while a combination of gas-phase, photolytic formation on aerosol, and vertical transport is responsible for daytime HONO between 200–300 m a.g.l. HONO removal is dominated by vertical transport below 20 m and photolysis between 200–300 m a.g.l

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Section: Model Descriptionmentioning

confidence: 99%

Modeling of daytime HONO vertical gradients during SHARP 2009

et al. 2013

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“…[52] A number of unsaturated hydrocarbons are known to react rapidly with NO 3 , such as monoterpenes [Calogirou et al, 1999;Martinez et al, 1999], phenol [Bolzacchini et al, 2001;Kurtenbach et al, 2002], or 2-methyl-2-butene [Atkinson, 1991]. For the budget of these organics it is likely that daytime NO 3 cannot be neglected in polluted situations.…”

Section: Voc Oxidation By Daytime Nomentioning

confidence: 99%

“…According to our calculations, the oxidation by OH and daytime NO 3 were equally important at La Porte. Although not directly measured at La Porte, it is possible to calculate the p-cresol concentration from the measured concentration of toluene during the day, as suggested by Kurtenbach et al [2002]. The calculation is based on the oxidation of toluene with OH, in which p-cresol is a product, which itself is destroyed by OH radicals and in our case also significantly by NO 3 .…”

Section: P-cresol Chemistrymentioning

confidence: 99%

“…The calculation is based on the oxidation of toluene with OH, in which p-cresol is a product, which itself is destroyed by OH radicals and in our case also significantly by NO 3 . We expanded the equation derived by Kurtenbach et al [2002] by including daytime NO 3 chemistry:…”

Section: P-cresol Chemistrymentioning

confidence: 99%

“…In a publication by [Pitts et al, 1984], however, elevated NO 3 observations are shown, but not further commented. Indirect evidence for a possible role of NO 3 during the day was recently found in urban air [Kurtenbach et al, 2002], where observed daytime ratios of p-cresol to toluene could only be explained by assuming oxidation of p-cresol by NO 3 at mixing ratios of $0.5 ppt NO 3 .…”

Section: Introductionmentioning

confidence: 97%

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Direct observations of daytime NO₃: Implications for urban boundary layer chemistry

et al. 2003

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[1] The nitrate radical (NO 3 ) is the dominant atmospheric oxidant during the night in most environments. During the day, however, NO 3 has thus far been considered insignificant. Here we present daytime measurements of NO 3 by Differential Optical Absorption Spectroscopy near Houston, Texas, during the Texas Air Quality Study 2000. On 3 consecutive days in August/September 2000, NO 3 reached levels from $5 ppt 3 hours before sunset to 31 ppt around sunset. Daytime NO 3 had a negligible effect on the photostationary state (PSS) between O 3 and NO x , with the exception of the last hour before sunset, when it significantly accelerated NO-to-NO 2 conversion. On August 31, chemical reactions involving NO 3 destroyed 8 (±4) ppb O x (= O 3 + NO 2 ) during the day and 27 (±6) ppb at night. NO 3 chemistry contributed 10 (±7)% to the total O x loss during the daytime, and 28% (±18%) integrated over a 24-hour period. It therefore played an important role in the O x budget. NO 3 also contributed significantly to the daytime oxidation of hydrocarbons such as monoterpenes and phenol in Houston. The observed daytime NO 3 mixing ratios can be described as a function of O 3 and NO x . Above [NO x ]/[O 3 ] ratios of 3%, daytime NO 3 becomes independent of NO x and proportional to the square of O 3 . Our calculations indicate that elevated (>1 ppt) NO 3 levels can be present whenever ozone mixing ratios exceed typical urban smog levels of 100 ppb.

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Rapid organic aerosol formation downwind of a highway: Measured and model results from the FEVER study

et al. 2014

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The Fast Evolution of Vehicle Emissions from Roadway (FEVER) study was undertaken to strategically measure pollutant gradients perpendicular to a major highway north of Toronto, Canada. A case study period was analyzed when there was an average perpendicular wind direction. Two independent, fast response measurements were used to infer rapid organic aerosol (OA) growth on a spatial scale from 34 m to 285 m at the same time as a decrease was observed in the mixing ratio of primary emitted species, such as CO 2 and NO x . An integrated organic gas and particle sampler also showed that near the highway, the aerosol had a larger semivolatile fraction than lower volatile fraction, but over a relatively short distance downwind of the highway, the aerosol transformed to being more low volatile with the change being driven by both evaporation of semivolatile and production of lower volatile organic aerosol. A new 1-D column Lagrangian atmospheric chemistry model was developed to help interpret the measured increase in the ΔOA/ΔCO 2 curve from 34 m to 285 m downwind of highway, where the Δ refers to background-corrected concentrations. The model was sensitive to the assumptions for semivolatile organic compounds (SVOCs). Different combinations of SVOC emissions and background mixing ratios were able to yield similar model curves and reproduce the observations. Future measurements of total gas-phase SVOC in equilibrium with aerosol both upwind and downwind of the highway would be helpful to constrain the model.

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Verification of the Contribution of Vehicular Traffic to the Total NMVOC Emissions in Germany and the Importance of the NO3 Chemistry in the City Air

Cited by 35 publications

References 26 publications

Modeling of daytime HONO vertical gradients during SHARP 2009

Modeling of daytime HONO vertical gradients during SHARP 2009

Direct observations of daytime NO₃: Implications for urban boundary layer chemistry

Rapid organic aerosol formation downwind of a highway: Measured and model results from the FEVER study

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Verification of the Contribution of Vehicular Traffic to the Total NMVOC Emissions in Germany and the Importance of the NO3 Chemistry in the City Air

Cited by 35 publications

References 26 publications

Modeling of daytime HONO vertical gradients during SHARP 2009

Modeling of daytime HONO vertical gradients during SHARP 2009

Direct observations of daytime NO3: Implications for urban boundary layer chemistry

Rapid organic aerosol formation downwind of a highway: Measured and model results from the FEVER study

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Direct observations of daytime NO₃: Implications for urban boundary layer chemistry