The document describes a test guideline (section 796.3900) which can be used under sections 4 and 5 of the Toxic Substances Control Act (TSCA) to regulate industrial chemicals. It describes structure/reactivity (S/R) relationships of Atkinson of the University of California/Riverside for estimating the second-order rate constant k(OH) and the associated half-life t(sub 1/2)E for the reaction of an organic chemical with hydroxyl radicals in the gas-phase in the troposphere. All pertinent parameters and equations are listed in the report to enable a scientist to calculate k(OH) and t(sub 1/2)E. Sixteen organic chemicals, covering a range of molecular structures, are used to illustrate the use of the S/R relationships of Atkinson to estimate k(OH). A hypothetical example is given to illustrate the use of these S/R relationships to define testing under section 4 of TSCA. A mathematical synopsis of the S/R relationships of Atkinson is given in Section IV of the report.

"EPA 700-R-92-003." Includes bibliographical references. "4. Rate of indirect photoreaction: screening test level guideline section 796.3900. Estimation of the estimation of the second-order rate constant for the reaction of organic chemicals in the troposphere." Microfiche.