Comparative analysis of chemical reaction mechanisms for photochemical smog

Leone, Joseph A.; Seinfeld, John H.

doi:10.1016/0004-6981(85)90166-0

Cited by 113 publications

(54 citation statements)

References 15 publications

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“…To further determine the cause of the observed differences between RACM and RADM2, three additional cases were simulated ( [Leone and Seinfeld, 1985] smaller because it has a much greater rate constant with HO which makes its loss by photolysis relatively less important.…”

Section: Datamentioning

confidence: 99%

A new mechanism for regional atmospheric chemistry modeling

Stockwell¹,

Kirchner²,

Kühn³

et al. 1997

J. Geophys. Res.

1,015

718

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Abstract. A new gas-phase chemical mechanism for the modeling of regional atmospheric chemistry, the "Regional Atmospheric Chemistry Mechanism" (RACM) is presented. The mechanism is intended to be valid for remote to polluted conditions and from the Earth's surface through the upper troposphere. The RACM mechanism is based upon the earlier Regional Acid Deposition Model, version 2 (RADM2) mechanism ] and the more detailed Euro-RADM mechanism [Stockwell and Kley, 1994]. The RACM mechanism includes rate constants and product yields from the most recent laboratory measurements, and it has been tested against environmental chamber data. A new condensed reaction mechanism is included for biogenic compounds: isoprene, a-pinene, and d-limonene. The branching ratios for alkane decay were reevaluated, and in the revised mechanism the aldehyde to ketone ratios were significantly reduced. The relatively large amounts of nitrates resulting from the reactions of unbranched alkenes with NO 3 are now included, and the production of HO from the ozonolysis of alkenes has a much greater yield. The aromatic chemistry has been revised through the use of new laboratory data. The yield of cresol production from aromatics was reduced, while the reactions of HO, NO3, and 03 with unsaturated dicarbonyl species and unsaturated peroxynitrate are now included in the RACM mechanism. The peroxyacetyl nitrate chemistry and the organic peroxy radical-peroxy radical reactions were revised, and organic peroxy radical + NO 3 reactions were added. IntroductionThe gas-phase chemical mechanism is one of the most important components of an atmospheric chemistry model. These models require high-quality gas-phase chemical mechanisms to calculate the concentrations of atmospheric chemical species. The concentrations of ozone and other air pollutants are determined by the emissions of nitrogen oxides and reactive organic species, gas-and aqueous-phase chemical reaction rates, deposition, and meteorological conditions. There are several important mechanisms which are widely used for modeling the chemistry of the troposphere including the mechanism of Lurmann et al. chemistry on a regional scale, we have named it the "Regional Atmospheric Chemistry Mechanism" (RACM). The RACM mechanism was created to be capable of simulating the troposphere from the Earth's surface through the upper troposphere and to be valid for simulating remote to polluted urban conditions.The mechanism includes 17 stable inorganic species, 4 inorganic intermediates, 32 stable organic species (4 of these are primarily of biogenic origin), and 24 organic intermediates (Table 1). The RACM mechanism includes 237 reactions ( Table 2). The mechanism and its use are described in the subsequent text. The text is divided into section 2 on the inorganic chemistry and section 3 on the organic chemistry. The organic chemistry section includes a description of the aggregation procedures for emissions and the development of the chemistry for alkanes, carbonyls, alkenes, aromatics; the decomposition...

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Section: Datamentioning

confidence: 99%

A new mechanism for regional atmospheric chemistry modeling

Stockwell¹,

Kirchner²,

Kühn³

et al. 1997

J. Geophys. Res.

1,015

718

View full text Add to dashboard Cite

show abstract

“…d Leone and Seinfeld (1985). e Estimated using crosssections for CHaOOCH 3 from DeMore et aL (1985) J value in s -l for 0 and 10 km.…”

Section: Reactionmentioning

confidence: 99%

A comparison of model calculations and measurements of acetone in the troposphere and stratosphere

1989

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We present 1-D eddy diffusion model calculations of the distributions of propane and acetone in the atmosphere for continental conditions. The magnitude of the surface seasonal variation in propane mixing ratios that we obtain is in general agreement with measurements at the surface and in the free troposphere. A comparison of the absolute values of the model with propane measurements suggests that a larger surface flux than we have used may be more appropriate for continental conditions. The acetone model results for summer conditions that we obtain are also in reasonable accord with measurements. However, we find serious disagreement between the model winter profiles of acetone and the measurements at the tropopause and in the lower stratosphere. The measured values are lower than the model values at 45" N by a factor of 7-30. In addition, it is also surprising that, given the relatively long lifetime of acetone, free tropospheric values of acetone more representative of surface values have not been measured. The results simulating the decay of elevated levels of propane in the upper troposphere caused by rapid convective transport of boundary layer air indicate that propane will be primarily dispersed by transport rather than destroyed photochemically. Thus, the impact on acetone and PAN is minimal.

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“…The simplest approach uses surrogate species not necessarily related to the emitted species in order to represent hydrocarbons released into the atmosphere (Hough, 1988). An example of this simplified lumping can be seen in Leone and Seinfeld (1985), where the total reactive hydrocarbon concentration is represented as 75% n-butene and 25% propene. These, coupled with four aldehyde species, are the only species used to represent organic compounds in the mechanism.…”

Section: Previous Approaches To Chemical Lumpingmentioning

confidence: 99%

Systematic reduction of complex tropospheric chemical mechanisms, Part II: Lumping using a time-scale based approach

2004

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Abstract. This paper presents a formal method of species lumping that can be applied automatically to intermediate compounds within detailed and complex tropospheric chemical reaction schemes. The method is based on grouping species with reference to their chemical lifetimes and reactivity structures. A method for determining the forward and reverse transformations between individual and lumped compounds is developed. Preliminary application to the Leeds Master Chemical Mechanism (MCMv2.0) has led to the removal of 734 species and 1777 reactions from the scheme, with minimal degradation of accuracy across a wide range of test trajectories relevant to polluted tropospheric conditions. The lumped groups are seen to relate to groups of peroxy acyl nitrates, nitrates, carbonates, oxepins, substituted phenols, oxeacids and peracids with similar lifetimes and reaction rates with OH. In combination with other reduction techniques, such as sensitivity analysis and the application of the quasi-steady state approximation (QSSA), a reduced mechanism has been developed that contains 35% of the number of species and 40% of the number of reactions compared to the full mechanism. This has led to a speed up of a factor of 8 in terms of computer calculation time within box model simulations.

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Comparative analysis of chemical reaction mechanisms for photochemical smog

Cited by 113 publications

References 15 publications

A new mechanism for regional atmospheric chemistry modeling

A new mechanism for regional atmospheric chemistry modeling

A comparison of model calculations and measurements of acetone in the troposphere and stratosphere

Systematic reduction of complex tropospheric chemical mechanisms, Part II: Lumping using a time-scale based approach

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