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
Citations
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Journal ArticleDOI
Atmospheric chemistry of peroxides: a review
TL;DR: Inorganic and organic peroxides have become the focus of increased attention by atmospheric chemists during the last decade as discussed by the authors, and they serve as an important link between gas phase radicals and aqueous phase chemistry in the atmosphere.
Journal ArticleDOI
Considerations regarding sources for formic and acetic acids in the troposphere
TL;DR: In this paper, the authors investigated the source of organic acidity in precipitation and found that organic acid in precipitation may originate with two major sources, volatile vegetative constituents over continents and a second weaker source in both continental and marine regions.
Journal ArticleDOI
On the Source of the Submicrometer Droplet Mode of Urban and Regional Aerosols
Zhaoyue Meng,John H. Seinfeld +1 more
TL;DR: In this paper, the authors examined the mechanisms of formation of the droplet mode and showed that growth of condensation mode particles by accretion of water vapor or by gas-phase or aerosol-phase sulfate production cannot explain the existence of droplet modes.
Journal ArticleDOI
Simulating equilibrium within aerosols and nonequilibrium between gases and aerosols
TL;DR: A numerical method to solve chemical equilibrium equations and a method of coupling the equilibrium calculations to nonequilibrium growth and evaporation are discussed in this paper, where the equilibrium program solves any number of equations for gas, aqueous, ionic, and solid equilibrium concentrations over large spatial grids and particle size grids.
Journal ArticleDOI
The STEM-II regional scale acid deposition and photochemical oxidant model—I. An overview of model development and applications
TL;DR: In this article, the authors described the combination of the STEM-II/ASM/RSM model and the Reactive Scavenging Model (RSM) for acid deposition.
References
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Book
CRC Handbook of Chemistry and Physics
TL;DR: CRC handbook of chemistry and physics, CRC Handbook of Chemistry and Physics, CRC handbook as discussed by the authors, CRC Handbook for Chemistry and Physiology, CRC Handbook for Physics,
Chemical kinetics and photochemical data for use in stratospheric modeling
W. B. Demore,J. J. Margitan,Mario J. Molina,R. T. Watson,D. M. Golden,R. F. Hampson,Michael J. Kurylo,Carleton J. Howard,A. R. Ravishankara +8 more
TL;DR: As part of a series of evaluated sets, rate constants and photochemical cross sections compiled by the NASA Panel for Data Evaluation are provided in this article, with particular emphasis on the ozone layer and its possible perturbation by anthropogenic and natural phenomena.
Journal ArticleDOI
Tropospheric chemistry: A global perspective
TL;DR: A model for the photochemistry of the global troposphere constrained by observed concentrations of H2O, O3, CO, CH4, NO, NO2, and HNO3 is presented in this paper.
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Selected values of chemical thermodynamic properties
TL;DR: The Selected Values of Chemical Thermodynamic Properties as mentioned in this paper, published by the National Bureau of Standards (NBS) in 1952, is a seminal work in the field of thermodynamics.