Gas and particle products distribution from the reaction of β-caryophyllene with ozone

Gas and particulate reaction products from the ozonolysis of beta-caryophyllene (I) in the presence of atmospheric air were investigated using a combination of gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC). A Scanning Mobility Particle Sizer system (3936, TSI) and a Condensation Particle Counter (3025A, TSI) were used to study secondary organic aerosol formation. The nighttime oxidation was carried out in a large outdoor smog chamber (190 m(3)). A wide range of ring retaining and ring opening products in the gas and particle phase are reported over the course of the reaction. On average, measured gas and particle phase products accounted for similar to64% of the reacted beta-caryophyllene (I) carbon. Measurements show that a number of reaction products with low vapor pressure (e.g., beta-caryophyllone aldehyde (IV), beta-norcaryophyllone aldehyde (V), beta-caryophyllonic acid (VIII), beta-14-hydroxycaryophyllonic acid (XIV)) were found in the sample taken during the first 20 min of the reaction and may play an important role in the early formation of secondary organic aerosol. A detailed mechanism is proposed to account for most products observed in this investigation.