||Experimental Protocol for Determining Ozone Reaction Rate Constants.
Pitts, Jr., James N. ;
Winer, Arthur M. ;
Fitz, Dennis R. ;
Aschmann, Sara M. ;
Atkinson, Roger ;
||California Univ., Riverside. Statewide Air Pollution Research Center.;Environmental Sciences Research Lab., Research Triangle Park, NC.
Reaction kinetics ;
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
An experimental protocol for the determination of room temperature rate constants for the reactions of ozone with chemicals in the gas phase has been developed and is described in detail. This protocol will thus provide a basis for evaluating the relative importance of one atmospheric reaction pathway (i.e. attack by ozone) of organic substances which may be emitted into the environment. The experimental technique is based upon monitoring the decay of ozone (initially present at approximately 1 ppm) in the presence and absence of known excess concentrations of the test compound, with pure air as a diluent gas. The ozone reaction rate constants are then calculated from the dependence of the observed ozone decay rates on the concentration of the test compound. The reactions are carried out in approximately 150-180 liter Teflon reaction bags. The reaction bag is initially divided into two approximately equal sub-chambers. Ozone rate constants 10 to the -20 cu cm/molecule/pec can be readily measured for test compound concentrations of approximately 0.1 torr (i.e. 100 ppm), which encompasses the reactivities of interest from an atmospheric point of view.