Investigation of reaction time on OH-initiated isoprene photooxidation experiment

Abstract

Abstract: OH – initiated photooxidation reaction of isoprene was performed in our home-made smog. Isoprene and important gas phase products (methacrolein and methyl vinyl ketone (m/z=70)) were monitored real time by proton-transfer-reaction mass spectrometer (PTR-MS), and formation and growth of SOA were measured by scanning mobility particles sizer (SMPS). Photoionization mass spectroscopy of important gas phase products from this photooxidation of isoprene was obtained using synchrotron radiation photoionization mass spectrometry (SRPIMS). It is shown that with increase of reaction time, isoprene concentration reduced gradually, SOA began to produce and grow; when isoprene was depleted nearly, the mass concentration of SOA was still kept to grow, which indicated that heterogeneous reaction of the main gas phase products occurred on the surface of particles should be responsible for the growth of SOA.

Key words: spectroscopy, isoprene, OH free radical, smog chamber, photooxidation products

CLC Number:

O437

PAN Gang, HU Chang-jin, WANG Zhen-ya, CHENG Yue, LIU Zhi, ZHENG Xiao-hong, GU Xue-jun, ZHAO Wei-xiong, ZHANG Wei-jun. Investigation of reaction time on OH-initiated isoprene photooxidation experiment[J]. J4, 2013, 30(3): 275-279.

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