Journal ArticleDOI
The photochemistry of a remote marine stratiform cloud
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In this article, coupled gas and aqueous-phase photochemistry of a stratiform cloud in a remote region of the marine atmosphere is investigated with a time-dependent box model.Abstract:
The coupled gas- and aqueous-phase photochemistry of a stratiform cloud in a remote region of the marine atmosphere is investigated with a time-dependent box model. Both scavenging of ambient acidic aerosols and gases as well as aqueous-phase chemical reactions within droplets are found to be important sources of acidity to cloud water and can lead to pH levels in cloud water in the remote marine atmosphere well below 5.6. The major sources of acidity via aqueous-phase chemical reactions are the generation of sulfuric acid from dissolved SO2 and the generation of formic acid from dissolved formaldehyde. In both cases, aqueous-phase free radicals can play a significant role either directly by oxidizing dissolved SO2 and HCHO or indirectly by producing the aqueous-phase oxidant H2O2. The rate of SO2 conversion to sulfuric acid is sensitive to a variety of parameters including the accommodation or sticking coefficient for SO2, H2O2, HO2, and OH, the liquid water content, and the ambient levels of SO2, HNO3, and other acidic or basic gases. Because high levels of SO2 tend to deplete cloud water of H2O3, the possibility exists that the pH of precipitation in polluted regions will respond nonlinearly to reduced SO2 emissions.read more
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Compilation of Henry's law constants (version 4.0) for water as solvent
TL;DR: According to Henry's law, the equilibrium ratio between the abundances in the gas phase and in the aqueous phase is constant for a dilute solution as discussed by the authors, and a compilation of 17 350 values of Henry's Law constants for 4632 species, collected from 689 references is available at http://wwwhenrys-law.org
Book
Fundamentals of atmospheric modeling
TL;DR: In this paper, the authors propose numerical solutions to partial differential equations and finite-differencing the equations of atmospheric dynamics, including boundary-layer and surface processes, and Radiative energy transfer.
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Mass-independent fractionation of sulfur isotopes in Archean sediments: strong evidence for an anoxic Archean atmosphere.
TL;DR: It is concluded that the atmospheric O2 concentration must have been < 10(-5) PAL prior to 2.3 Ga, which would have meant that all sulfur-bearing species would have passed through the oceanic sulfate reservoir before being incorporated into sediments, so any signature of MIF would have been lost.
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Photodissociation in the atmosphere: 1. Actinic flux and the effects of ground reflections and clouds
TL;DR: In this paper, it was shown that photodissociation rate coefficients inside clouds, and particularly inside cloud droplets, can frequently exceed the clear-sky values, in contrast to current usage in cloud chemistry models, due to the ∼2 cos θ factor incurred in the actinic flux when the solar beam is scattered and diffused into nearly isotropic light.
Journal ArticleDOI
Carboxylic acids in the troposphere, occurrence, sources, and sinks: A review
A. Chebbi,P. Carlier +1 more
TL;DR: In this paper, a synthesis of low molecular weight carboxylic acids in tropospheric aqueous and gaseous phases and in aerosol particles for different environments is presented.
References
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Kinetic study of the equilibrium HO2 + NO .dblarw. OH + NO2 and the thermochemistry of HO2
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Atmospheric SO/sub 2/ measurements on Project GAMETAG
TL;DR: In this paper, a simple chemical model was used to conclude that a significant amount of background SO/sub 2/ may originate from the oxidation of OCS, which is a common source of SO in tropical oceans.
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Wavelength dependence of the primary processes in acetaldehyde photolysis
Abraham Horowitz,Jack G. Calvert +1 more
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Measurements of hydrogen peroxide in rainwater
TL;DR: The hydrogen peroxide (H 2 O 2 ) concentration of rainwater falling in Claremont, California has been measured over a series of precipitation events as discussed by the authors, and the measured values were typically 1-160 ppb, but on three occasions H 2 O O 2 levels in excess of 1 ppm were measured.
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Latitudinal distributions of CO and CH4 over the Pacific
TL;DR: In this article, the authors used the Gametag (Global Atmospheric Measurements Experiment of Tropospheric Aerosols and Gases) data to detect changes in the atmospheric abundances of CO and CH4 from 1972 to 1978 outside the uncertainty limits.