F. Kirchner et Wr. Stockwell, EFFECT OF PEROXY RADICAL REACTIONS ON THE PREDICTED CONCENTRATIONS OFOZONE, NITROGENOUS COMPOUNDS, AND RADICALS, JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 101(D15), 1996, pp. 21007-21022
The reactions of organic peroxy radicals with NO, HO2, organic peroxy
radicals, and NO3 along with the formation and decomposition of peroxy
acetyl nitrate are all important for the modeling of atmospheric chemi
stry. Recent laboratory measurements of the rate constants for peroxy
radical-peroxy radical reactions show that there are large differences
between these rate constants. We present methods of estimating organi
c peroxy radical self-reaction rate constants from an empirical expres
sion. These self-reaction rate constants may be used to estimate the r
ates of peroxy radical cross reactions. There are also new data availa
ble on the rate constants for peroxyacetyl nitrate formation, decompos
ition, the reaction of acetyl peroxy radicals and other organic peroxy
radicals with NO, and the reactions of NO3 with organic peroxy radica
ls. To estimate the importance of these reactions, these new data alon
g with revisions to the product yields for organic peroxy radical-orga
nic peroxy radical reactions were implemented in the mechanism of Stoc
kwell et al. [1990]. The revised mechanism yields significantly differ
ent concentrations of peroxyacetyl nitrate, higher organic hydroperoxi
des and peroxyacetic acid concentrations. Nighttime concentrations of
organic peroxy radicals, HO2, HO, and NO3 are also strongly affected b
y organic peroxy radical-organic peroxy radical reactions and the reac
tions of organic peroxy radicals with NO3. Our results suggest that th
e reactions of organic peroxy radicals with NO3 are more important tha
n organic peroxy radical-organic peroxy radical reactions in the night
time atmosphere.