Abstract |
A reactive hydrocarbon analyzer (RHA), based on the chemiluminescent reaction of hydrocarbons with oxygen atoms, is used to provide a rapid indication of reactivity weighted hydrocarbon mass in automobile exhaust. Samples are reported by their ethylene-equivalent concentration--the concentration of ethylene which would give the same mass-reactivity product as the exhaust hydrocarbon mixture. These are compared to ethylene-equivalent concentrations obtained by the much more cumbersome procedure of weighting the individual sample hydrocarbons, determined by gas chromatography (GC), by their respective relative short-term photochemical reactivities, summing these results, and equating them to ethylene. Procedures are also described to eliminate a negative interference to the RHA method resultant from H2O quenching of the chemiluminescence emitter. The RHA and GC ethylene-equivalent concentrations correlate within 5%. (Copyright (c) 1977 by the American Chemical Society.) |