Atmospheric chemistiy

Vernon A, Church T, Patterson C, et al. 1992. Continental origin and industrial sources of tiace-metals in the northwest atlantic tioposphere. Journal of Atmospheric Chemistiy 14 339-351. 

Atkinson, R., D. L. Baulch, R. A. Cox, R. F. Hampson, Jr., J. A. Kerr, M. J. Rossi, and J. Troe, Evaluated Kinetic, Photochemical, and Heterogeneous Data for Atmospheric Chemistiy Supplement V, IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry, J. Phys. Chem. Ref. Data, 26, 521-1011 (1997a). 

Centre for Atmospheric Chemistiy, York University, 4700 Keele Street, Toronto, Ontario, Canada, M3J1P3 Corresponding author. 

Our understanding of natural water systems has, until recently, been seriously limited by a lack of kinetic information on critical reactions in water, in sediments, and at interfaces. Earlier in atmospheric chemistiy (Seinfeld, 1986) and more recently in aquatic chemistry (Brezonik, 1993), a considerable growth of information on rates and mechanisms for reactions central to environmental chemistry has taken place. As a result, we are now better able to assess the characteristic time scales of chemical reactions in the environment and compare these with, for example, residence times of water in a system of interest. Schematically, as shown here, for chemical vs. fluid time scales... 

Ravishankara A.R. Introduction Atmospheric Chemistiy-Long-Term Issues, Chem. Rev. 103 (2003) 4505 -4508. 

Caibon monoKide, 85-86 atmospheric effects, 42 atmospheric chemistiy, 239-244 atmospheric concenti ations, diy deposition velocity, 969 global budget, 85-86 lifetimes, 1099 reactivity, 312... 

It is feasible to give only a very limited introduction at this point to atmospheric chemistiy essential to air pollution processes, and the interested reader is referred to other sources. Sunshine is the key ingredient driving atmospheric chemical change and two photochemical processes stand out as most influential in air pollution... 

PhotDdissociatiOTi leads to bond breaking and is of central importance in atmospheric chemistiy for free radical production. Photodissociation is well studied for electTOTiic transitions, and this will not be reviewed here. Direct excitation of vibratiOTiaUy excited states, which have sufficient energy to dissociate, can occur with visible solar radiatimi this process is discussed below. 

Another important problem in the atmospheric chemistiy models of Titan is the handling of the uncertainty of reaction branching ratios. This can be an important issue for the uncertainty analysis of many other reaction kinetic models. Chemical kinetic databases provide the uncertainty of rate coefficients independently of each other. Yet, for multichannel reactions using a direct method, it is easier to measure the overall rate coefficient than the rate coefficients of the constituent reaction steps. The branching ratios are then determined in other measurements. However, it is important to note that the branching ratios are correlated, since their sum has a unit value. Carrasco et al. (Carrasco and Pemot 2007 Plessis et al. 2010) demonstrated that the correlated branching ratios follow a Dirichlet distribution. The method was applied to the case of Titan ionospheric chemistry and used for the estimation of the effect of branching ratio correlations on the uncertainty of calculated concentrations. 

Cmtzen, P.J. Oberlander, E. Peters, W. Rompp, A., 2001 Overview of Atmospheric Chemistiy , in Moortgat, G. (Ed.) Chemical, Physical and Biogenic Processes. Notes from the 3rd COACh Intemahonal School (Mainz Max-Planck-Inshtut fiir Chemie) 7—17. 

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