ATMOSPHERIC AND INDOOR CHEMISTRY OF GAS-PHASE INDOLE, QUINOLINE, AND ISOQUINOLINE

The gas-phase chemistry of the nitrogen-containing organic compounds i ndole, quinoline and isoquinoline, which are present in environmental tobacco smoke, has been investigated. No photolysis of these nitrogen heterocycles was observed under indoor ''white'' fluorescent lighting conditions. Rate constants for the gas-phase reactions of these compou nds with OH radicals, NO3 radicals, NO2, and O-3 were measured, and th e rate constants obtained (in cm(3) molecule(-1) s(-1) units) were: fo r reaction with the OH radical: indole, (1.54+/-0.35)x10(-10); quinoli ne, (1.16+/-0.55)x10(-11); isoquinoline, (8.5+/-3.6)x10(-12); for reac tion with the NO3 radical: indole, (1.3+/-0.5)x10(-10) for reaction wi th NO2: indole, < 2 x 10(-19); quinoline, < 1.6 x 10(-20) isoquinoline , < 1.1 x 10(-19) and for reaction with O-3: indole, (4.9+/-1.8)x10(-1 7); quinoline, < 1.0x10(-19); and isoquinoline, < 1.1x10(-19). Evidenc e was obtained that quinoline reacts with gas-phase nitric acid and th is is also expected to be the case for isoquinoline. These data indica te that in indoor environments, quinoline and isoquinoline will be lar gely removed by air exchange unless gas-phase nitric acid is present, while indole will be removed by chemical reaction if NO3 radicals are present at part-per-trillion levels. Products of the O-3 and OH radica l reactions with indole have been studied and the possible O-3 reactio n mechanism is discussed.