Hydrocarbon Reactivity and the Kinetics of the Atmospheric Photooxidation of Nitric Oxide

Effects of hydrocarbon and nitrogen oxides on photochemical smog formation

“…At constant hc:NOz ratio, RNo, increased with increasing NOz because of the hc effect. Such dependence of Rno, on hc and NO,-was similar to reported patterns (Glasson and Tuesday, 1966) for single hc:NOz systems.…”

“…Patterns that describe dependence of other reactivity manifestations on hc and NOz were generally in good agreement with those reported (Altshuller et al, 1969;Buchberg et al, 1963;Glasson and Tuesday, 1966;Korth et al, 1964;Altshuller etal., 1970;Stephens and Burleson, 1969). Within the range of initial concentration levels used in this research, these dependencies are as follows: At low NOz levels, the N02 dosage is nearly proportional to NOz and is slightly inhibited by hc at higher hc levels, the HCHO dosage is nearly propor-tional to hc level and slightly inhibited by NO,, and rate of NG2 formation is nearly proportional to hc and varies similarly with NOz in the lower NO, level range; at higher NO, levels, Rno, is nearly independent of NOz.…”

“…The role of hc and NOz in smog phenomena had been studied (Altshuller et al, 1969;Buchberg et al, 1963; Glasson and Tuesday, 1966;Romanovsky et al, 1967;Hamming and Dickinson, 1966;Korth et al, 1964;Nicksic et al, 1966); however, interpretation of those earlier data was subject to uncertainty because test conditions and/or samples differed from those representing a typical urban atmosphere. In this study, composition and levels of the hc and NO, reactants in the test mixtures were controlled to approximate pollutant makeup in present-day problem atmospheres and in atmospheres anticipated as a result of current controls.…”

The Reactivities of Gasoline Vapors in Photochemical Smog

“…12 Each of the gasolines was irradiated (at a hydrocarbon concentration of 2 ppm expressed as C6 with 1.0 ppm NO X at 60% relative humidity) in the small glass chamber. For the relative rates of NO 2 formation, agreement between calculated and observed values is remarkably good, which supports Glasson and Tuesday's observation 14 that excellent agreement exists between measured and predicted NO2 photooxidation rates with actual gasolines. However, by measurement or calculation, the smog-forming properties of the whole gasolines used in the present study do not vary over a wide range (relative reactivity factors 1.4 to 1.0).…”

Reactivities of complex hydrocarbon mixtures

“…However, such strategies are based upon assumptions that the present hydrocarbon composition will be maintained and perhaps the present HC /NO* ratio as well. Previous laboratory chamber studies have shown that different hydrocarbons as well as different HC/NO* ratios, show wide variations in oxidant formation (1)(2)(3). Studies have shown that not only is the HC/NO* ratio altered with the new vehicles, but that the hydrocarbon composition is altered when exhaust is catalytically treated (4).…”