Journal ArticleDOI
The free radical chemistry of cloud droplets and its impact upon the composition of rain
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In this article, the authors simulate the free radical chemistries of the gas phase and aqueous phase within a warm cloud during midday solar fluxes and demonstrate that the scavenging of OH and HO2 from cloud droplets can represent a major source of free radicals to cloud water provided the accommodation or sticking coefficient for these species impinging upon water droplets is not less than 0.0001.Abstract:
Calculations are presented that simulate the free radical chemistries of the gas phase and aqueous phase within a warm cloud during midday. It is demonstrated that in the presence of midday solar fluxes, the heterogeneous scavenging of OH and HO2 from the gas phase by cloud droplets can represent a major source of free radicals to cloud water, provided the accommodation or sticking coefficient for these species impinging upon water droplets is not less than 0.0001. The aqueous-phase of HO2 radicals are found to be converted to H2O2 by aqueous-phase chemical reactions at a rate that suggests that this mechanism could produce a significant fraction of the H2O2 found in cloud droplets. The rapid oxidation of sulfur species dissolved in cloudwater by this free-radical-produced H2O2 as well as by aqueous-phase OH radicals could conceivably have a significant impact upon the chemical composition of rain.read more
Citations
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Journal ArticleDOI
Scavenging ratios, wet deposition, and in‐cloud oxidation: An application to the oxides of sulphur and nitrogen
TL;DR: In this article, a model relating daily average ground level scavenging ratios (W) to nucleation scavenging and in-cloud chemical transformation is introduced and used as guidance in the regression analysis of 3 years of SO4= and NO3− scavenging-ratio observations made at six locations in eastern Canada.
Journal ArticleDOI
A study of the spectra and reactivity of oxysulphur-radical anions involved in the chain oxidation of S(IV): A pulse and γ-radiolysis study
TL;DR: The rate constants for each of the steps in the freeradical-chain oxidation mechanism at pH 4 and 9 have been determined either by pulse radiolysis or a combination of pulse and steady-state radiolyysis.
Journal ArticleDOI
OH measurements during the First Aerosol Characterization Experiment (ACE 1): Observations and model comparisons
Roy L. Mauldin,Gregory J. Frost,G. Chen,David J. Tanner,André S. H. Prévôt,Douglas D. Davis,Fred Eisele +6 more
TL;DR: In this article, an inlet for the straightening and slowing of the airflow, calibration, and measurement considerations at changing pressure altitudes were discussed. But the results of the measurements in the boundary layer and those in and around clouds, with the model overestimating the hydroxyl radical by ∼40% in boundary layer or inside clouds, and underestimating it by ∼30% near clouds.
Journal ArticleDOI
Influence of transition metal complexes on atmospheric droplet acidity
TL;DR: In this paper, the relative importance of transition metal catalysts in atmospheric droplet chemistry, especially reactions that increase the net acidity of atmospheric droplets, has been evaluated, and it was shown that transition metal reactions are the principal sources of free radicals in cloud droplets and that a catalytic cycle involving the Fe(II)−Fe(III) couple is an efficient producer of organic acids from oxidation of ubiquitous atmospheric aldehydes.
Journal ArticleDOI
Oxidant abundances in rainwater and the evolution of atmospheric oxygen.
TL;DR: The upper limit for pO2 during early and mid-Precambrian time suggested by the incomplete oxidation of FeO in soils developed on basaltic rocks is affected only slightly by the presence of photochemical products in rainwater.
References
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Book
Microphysics of Clouds and Precipitation
TL;DR: In this article, the authors focus on one major aspect of cloud microphysics, which involves the processes that lead to the formation of individual cloud and precipitation particles, and provide an account of the major characteristics of atmospheric aerosol particles.
Journal ArticleDOI
Rate Constants for Reactions of Inorganic Radicals in Aqueous Solution
TL;DR: In this article, rate constants have been compiled for reactions of various inorganic radicals produced by radiolysis or photolysis, as well as by other chemical means in aqueous solutions.
Book
The physics of clouds
F. H. Ludlam,Basil John Mason +1 more
TL;DR: In the last fifteen years there has been a surge of activity in this science under the stimulus of development in civil and military aviation as discussed by the authors, and the growth of cloud physics during this period has been fostered not only by this general invigoration, but also by recognition of the practicability of exerting some influence upon the behaviour of clouds and their capacity for producing rain, hail, lightning and other meteorological phenomena.
Journal ArticleDOI
Normal atmosphere: large radical and formaldehyde concentrations predicted.
TL;DR: A radical chain reaction is proposed for the rapid removal of carbon monoxide, leading to acarbon monoxide lifetime as low as 0.2 year in the surface atmosphere.
Book
Highly dispersed aerosols
N.A. Fuchs,A.G. Sutugin +1 more
TL;DR: In this article, the processes leading to the formation of high-dispersed aerosols with particle size below 0.1 μ and the methods of generation and investigation of these aerosols are treated as well as their physical properties differing fundamentally from those of coarse aerosols.