Abstract: A laboratory study was carried out to investigate the secondary organic aerosol (SOA) products from photooxidation of the aromatic hydrocarbon ethylbenzene. The experiments were conducted by irradiating ethylbenzene/CH3ONO/NOx mixtures in a home-made smog chamber. Size distribution of the secondary organic aerosol particles was detected with an aerodynamic particle sizer spectrometer. The aerosol time-of-flight mass spectrometer (ATOFMS) was used to measure the chemical composition of individual secondary organic aerosol particle in real time. According to a large number of single aerosol mass spectra, the chemical composition of SOA was obtained statistically. The possible reaction mechanisms leading to these products were also discussed.

Key words: Ethylbenzene, Secondary organic aerosol, Smog chamber, Laser desorption/ ionization, Reaction mechanisms