Secondary organic aerosol (SOA) accounts for a significant fraction of ambient tropospheric aerosol and a detailed knowledge of the formation, properties and transformation of SOA is therefore required to evaluate its impact on atmospheric processes, climate and human health. The chemical and physical processes associated with SOA formation are complex and varied, and, despite considerable progress in recent years, a quantitative and predictive understanding of SOA formation does not exist and therefore represents a major research challenge in atmospheric science. This review begins with an update on the current state of knowledge on the global SOA budget and is followed by an overview of the atmospheric degradation mechanisms for SOA precursors, gas-particle partitioning theory and the analytical techniques used to determine the chemical composition of SOA. A survey of recent laboratory, field and modeling studies is also presented. The following topical and emerging issues are highlighted and discussed in detail: molecular characterization of biogenic SOA constituents, condensed phase reactions and oligomerization, the interaction of atmospheric organic components with sulfuric acid, the chemical and photochemical processing of organics in the atmospheric aqueous phase, aerosol formation from real plant emissions, interaction of atmospheric organic components with water, thermodynamics and mixtures in atmospheric models. Finally, the major challenges ahead in laboratory, field and modeling studies of SOA are discussed and recommendations for future research directions are proposed.

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The formation, properties and impact of secondary organic aerosol: current and emerging issues

http://joenschem.com/yahoo_site_admin/assets/docs/atkinson2000r.93190106.pdf

Atmospheric chemistry of VOCs and NOx

https://ams.confex.com/ams/pdfpapers/71176.pdf

Fully coupled “online” chemistry within the WRF model

Atmospheric degradation of volatile organic compounds

We present a first description and evaluation of GEOS-CHEM, a global three-dimensional (3-D) model of tropospheric chemistry driven by assimilated meteorological observations from the Goddard Earth Observing System (GEOS) of the NASA Data Assimilation Office (DAO). The model is applied to a 1-year simulation of tropospheric ozone-NOx-hydrocarbon chemistry for 1994, and is evaluated with observations both for 1994 and for other years. It reproduces usually to within 10 ppb the concentrations of ozone observed from the worldwide ozonesonde data network. It simulates correctly the seasonal phases and amplitudes of ozone concentrations for different regions and altitudes, but tends to underestimate the seasonal amplitude at northern midlatitudes. Observed concentrations of NO and peroxyacetylnitrate (PAN) observed in aircraft campaigns are generally reproduced to within a factor of 2 and often much better. Concentrations of HNO3 in the remote troposphere are overestimated typically by a factor of 2-3, a common problem in global models that may reflect a combination of insufficient precipitation scavenging and gas-aerosol partitioning not resolved by the model. The model yields an atmospheric lifetime of methylchloroform (proxy for global OH) of 5.1 years, as compared to a best estimate from observations of 5.5 plus or minus 0.8 years, and simulates H2O2 concentrations observed from aircraft with significant regional disagreements but no global bias. The OH concentrations are approximately 20% higher than in our previous global 3-D model which included an UV-absorbing aerosol. Concentrations of CO tend to be underestimated by the model, often by 10-30 ppb, which could reflect a combination of excessive OH (a 20% decrease in model OH could be accommodated by the methylchloroform constraint) and an underestimate of CO sources (particularly biogenic). The model underestimates observed acetone concentrations over the South Pacific in fall by a factor of 3; a missing source from the ocean may be implicated.

/pdf/global-modeling-of-tropospheric-chemistry-with-assimilated-4jwui0m63q.pdf

Global modeling of tropospheric chemistry with assimilated meteorology : Model description and evaluation

: Military jet aircraft flight procedures make it necessary to jettison excess fuel in the event of certain in-flight operational situations These fuel expulsions can be sizable, and in the presence of sunlight and NOx emissions from engine exhaust there exists the potential for formation of ozone and other manifestations of photochemical smog Since these fuel dumping procedures are carried out at elevated altitudes the atmospheric properties involved are significantly different from those at ground level (Author)

/pdf/high-altitude-jet-fuel-photochemistry-1hg00ge7rr.pdf

High Altitude Jet Fuel Photochemistry.

During the three-year cooperative agreement, the kinetic, mechanistic and product data available in the literature for the gas phase reactions of OH radicals and of O3 with organic compounds were evaluated and critically reviewed. Two review articles, one on O3 reactions, the other on OH radical reactions, resulting from the work were submitted for publication to Chemical Reviews. The review dealing with O3 reactions was published in Chemical Reviews, 84, 437-470 (1984), and the OH reaction review was accepted for publication. In addition to these extensive reviews, an experimental program was carried out to obtain needed kinetic data for selected OH radical and O3 reactions. The data, and the experimental techniques used, are summarized in the report, together with a discussion of a-priori predictive techniques for the estimation of OH radical and O3 reaction rate constants for organics for which experimental data are not available.

Atmospheric fates of organic chemicals: prediction of ozone and hydroxyl radical reaction rates and mechanisms. Final report, February 1982-February 1985

Kinetics of the gas-phase reactions of nitrate radicals with a series of aromatics at 296 .+-. 2 k

An experimental protocol for the determination at room temperature of rate constants for the reactions of hydroxyl radicals with organic chemicals in the gas phase is described in detail. This protocol provides a basis for evaluating the reactivity of organic substances which are emitted into the environment and which are consumed primarily by reaction with hydroxyl radicals. The experimental technique is based upon monitoring the disappearance rates of the test compound and of a reference organic in irradiated methyl nitrite-NO-organic-air mixtures.

Experimental protocol for determining hydroxyl radical reaction rate constants for organic compounds: estimation of atmospheric reactivity. Interim report

William P. L. Carter

Papers

High Altitude Jet Fuel Photochemistry.

Atmospheric fates of organic chemicals: prediction of ozone and hydroxyl radical reaction rates and mechanisms. Final report, February 1982-February 1985

Kinetics of the gas-phase reactions of nitrate radicals with a series of aromatics at 296 .+-. 2 k

Experimental protocol for determining hydroxyl radical reaction rate constants for organic compounds: estimation of atmospheric reactivity. Interim report

Environmental chamber studies of ozone impacts of coatings VOCs