Project Details:

Modeling Life Time and Degradability of Organic Compounds

1. collect existing quantitative models for estimating (predicting) tropospheric degradation of organic chemicals.

2. Develop a set of eval. crit. for the quality of these approaches starting with a) non-class specific approaches (such as the Athenison fragment contribution method) and b) QSAR models based on linear correlation of OH(NO3) reactivity with ionization energies. All models will be evaluate in terms of their accuracy and range of applicability with particular emphasis on their precision and on the advantage and limitations of each of them. The result will be recommendations for reliable application of predictive models for estimating lifetimes and degradation of organic compounds in air.

The ability to measure or accurately estimate degradation processes if of critically important to environ. risk assessment of comm. chem. In the troposphere for most of their reactions with OH and (at night) NO3 radicals are the most import. Lab. meas. of these reaction rates are costly and time consuming and only a few hundreds are avail. Thus it is an imperative to dev. methods that will predict reactivity and lifetime for large sets of chem. for reliable risk assessment. So far there are 3 approaches for such estimates a) fragment contrib. meth. b) QSAR based on physico-chemical data and c) ab initio MO calculation (environ. quantum chemistry) since the project will analyze and evaluate these models there is a necessity that it is done by IUPAC.

Project completed - Conference proceedings published in PureAppl. Chem.,70(7), 1319-1394, 1998, and Chemosphere.