Kinetics of the reactions of soot surface-bound polycyclic aromatic hydrocarbons with O3.
The kinetics of the heterogeneous reactions of O(3) with 17 polycyclic aromatic hydrocarbons (PAHs) present on laboratory generated kerosene soot surface was studied at T=255-330 K in a low pressure flow reactor combined with an electron-impact mass spectrometer. The kinetics of soot-bound PAHs consumption in reaction with O(3) was monitored using off-line HPLC measurements of their concentrations in soot samples as a function of time of exposure to O(3). Concentration of ozone in the gas phase was analyzed by mass spectrometry. The first-order rate constants measured for individual PAHs ranged from 0.004 to 0.008 s(-1) and were found to be independent of the ozone concentration ([O(3)]=(0.5-92) x 10(12) mol cm (-3)) and temperature (255-330 K). Results show that reaction with ozone can be an important degradation pathway of the particulate PAHs in the atmosphere.
Bedjanian
Yuri
Y
Institut de Combustion, Aérothermique, Réactivité et Environnement (ICARE), CNRS, 45071 Orléans Cedex 2, France. bedjanian@cnrs-orleans.fr
Nguyen
Mai Lan
ML
D000393:Air Pollutants / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D007700:Kinetics; D013058:Mass Spectrometry; D010126:Ozone / Q000737:chemistry*; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*; D011312:Pressure; D053260:Soot / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature
D000393:Air Pollutants; D011084:Polycyclic Aromatic Hydrocarbons; D053260:Soot; D010126:Ozone