Measurement of ultraviolet radiation intensity in photochemical smog studies
Abstract
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.
Additional Information
© 1973 American Chemical Society. Received for review August 12, 1972. Accepted December 27, 1972.Additional details
- Eprint ID
- 102630
- DOI
- 10.1021/es60078a002
- Resolver ID
- CaltechAUTHORS:20200417-142717806
- Created
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2020-04-17Created from EPrint's datestamp field
- Updated
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2023-04-13Created from EPrint's last_modified field