Chemical kinetic data needs for modeling the lower troposphere

Abstract

It is increasingly recognized that the integrity of the data input is one of the most serious limiting factors in modeling complex chemical systems. The reliability of the results generated in modeling studies is critical considering their application to environmental regulation and control. The purpose of this workshop was to bring together modelers, chemical kineticists, theoreticians and program managers, in order to define the critical data needs for modeling the troposphere. This collection of review papers, comments, and recommendations should serve a wide community of atmospheric scientists in identifying and attacking priority problem areas. The National Bureau of Standards is pleased to be responsible for this publication, and to have joined with the Environmental Protection Agency as cosponsors of the workshop.

Kinetics of the reactions of OH radicals with n‐alkanes at 299 ± 2 K

“…(1) OH + alkane1 -products (2) OH + alkane2 -products and since the alkanes are consumed essentially solely (>99% [S]) by reaction with OH radicals, and since dilution due to sampling is avoided by use of a collapsible Teflon reaction bag, then [7,8] In the presence of added alkanes, the OH radicals generated from the where k1 and kz are the OH radical rate constants for reactions (1) and (2) Figures 1-3, and the rate constant ratios kllk2 obtained from these plots by least-squares analyses are given in Table I.…”

An Experimental Protocol for the Determination of OH Radical Rate Constants with Organics Using Methyl Nitrite Photolysis as an OH Radical Source

“…OH + reference organic -> products (2) and, providing that the organics are consumed only by reaction with OH radicals, then In order to suppress O 3 formation, NO is added to the reaction mixture, which typically consists of ~10 ppm of CH3ONO, 5 ppm of NO, and ~1 ppm each of the test and reference organic in pure air diluent.…”

The weakly exothermic rearrangement of methoxy radical (CH3O⋅) to the hydroxymethyl radical (CH2OH⋅)

“…Subsequently, Radford discovered that the source of the H0 2 " radicals was the hydroxymethyl radical reaction (4) which he established to be much faster (rate coefficient about 3000 times greater) than the analogous methoxy reaction (3). As Radford noted, "this has importance for atmospheric chemistry, for if isomeric rearrangement of CH 3 0" to CH 2 0H" can occur even to a small extent, then the oxidation of CH 3 0" in the upper atmosphere may be governed by unimolecular isomerization rather than by the bimolecular reaction."…”