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Measurement of ultraviolet radiation intensity in photochemical smog studies

Holmes, John R. and O'Brien, Robert J. and Crabtree, James H. and Hecht, Thomas A. and Seinfeld, John H. (1973) Measurement of ultraviolet radiation intensity in photochemical smog studies. Environmental Science and Technology, 7 (6). pp. 519-523. ISSN 0013-936X. doi:10.1021/es60078a002.

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The most widely used technique of measuring ultraviolet radiation intensity in photochemical smog studies is to irradiate NO₂ in a nitrogen atmosphere. In the past a fictitious first-order rate constant, k_d, has been used to characterize the nonlinear NO₂-time behavior in such a system. The inadequacy in the use of k_d stems from the need to extrapolate the NO₂-time curve to zero time. The actual photolysis rate constant for NO₂ dissociation, k₁, provides an unambiguous measure of uv intensity. If the NO₂ photolysis is performed in the usual fashion, we show that k₁ can be computed directly from the NO₂-time data by the equation, k₁ = 1/(2Δt){(1 + R₁ -R₂) ln [NO₂]₀/[NO₂] + R₂[[NO₂]₀/[NO₂] - 1] where the constants R_i are defined in the text. The validity of this equation has been established both experimentally and by computer simulation.

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Seinfeld, John H.0000-0003-1344-4068
Additional Information:© 1973 American Chemical Society. Received for review August 12, 1972. Accepted December 27, 1972.
Issue or Number:6
Record Number:CaltechAUTHORS:20200417-142717806
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Official Citation:John R. Holmes, Robert J. O'Brien, James H. Crabtree, Thomas A. Hecht, and John H. Seinfeld Environmental Science & Technology 1973 7 (6), 519-523 DOI: 10.1021/es60078a002
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:102630
Deposited By: George Porter
Deposited On:17 Apr 2020 22:21
Last Modified:13 Apr 2023 18:53

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