FTIR ANALYSIS OF AEROSOL FORMED IN THE PHOTOOXIDATION OF 1,3,5-TRIMETHYLBENZENE

The composition of aerosol generated in the photooxidation of 1,3,5-tr imethylbenzene was investigated in a smog chamber experiment, The rela tive concentrations of alcohols, carboxylic acids, organonitrates, car bonyl groups, nitroaromatics, aliphatic C--H and aromatic C--H in the aerosol were estimated through analysis of infrared spectra. Based on model compound calibrations it was estimated that a typical molecule i n the aerosol contained three carbonyl groups, six aliphatic C-H bonds , and one hydroxyl group, Small amounts of organic acids (one molecule in ten) and organonitrates (one molecule in four) were observed. Abou t 5-10 wt% of the aerosol mixture was aromatic and these structures co ntained nitro and hydroxyl groups. This information on aerosol chemica l functionality was coupled with gas-phase chemistry mechanisms to pro pose potential aerosol formation pathways. (C) 1997 American Associati on for Aerosol Research.