Quinone Emissions from Gasoline and Diesel Motor Vehicles

Gas- and particle-phase emissions from gasoline and diesel vehicles operated on chassis dynamometers were collected using annular denuders, quartz filters, and PUF substrates. Quinone species were measured using O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine derivatization in conjunc tion with gas chromatography−mass spectrometry and high-performance liquid chromatography−mass spectrometry. Nine quinones were observed, ranging from C₆ to C₁₆. New species identified in motor vehicle exhaust include methyl-1,4-benzoquinone, 2-methyl-1,4-naphthoquinone (MNQN), and aceanthrenequinone. Gas-phase motor vehicle emissions of quinones are also reported for the first time. Six gas-phase quinones were quantified with emission rates of 2−28 000 μg L^-1 fuel consumed. The most abundant gas-phase quinones were 1,4-benzoquinone (BQN) and MNQN. The gas-phase fraction was ≥69% of quinone mass for light-duty gasoline emissions, and ≥84% for heavy-duty diesel emissions. Eight particle-phase quinones were observed between 2 and 1600 μg L^-1, with BQN the most abundant species followed by 9,10-phenanthrenequinone and 1,2-naphthoquinone. Current particle-phase quinone measurements agree well with the few available previous results. Further research is needed concerning the gas−particle partitioning behavior of quinones in ambient and combustion source conditions.