利用烟雾箱反应装置, 开展了OH自由基启动的异戊二烯光氧化生 成二次有机气溶胶(SOA)反应的研究。 用质子转移质谱仪(PTR-MS)监测反应物异戊二烯浓度、气相产物异丁烯醛和甲基乙烯酮(m/z=70)浓度随反应时间的变化; 用扫描电迁移率粒径谱仪(SMPS)监测二次有机气溶胶产生和生长过程;用同步辐射光电离质谱仪(SRPIMS)检 测不同反应时刻的光氧化气相产物的质谱。实验数据显示随着反应时间的增长, 异戊二烯浓度逐渐减少, 主要气相产物的浓度逐渐增加, SOA逐渐产生和增长;当异戊二烯快要消耗完时, SOA仍然继续增长。 它表明由于有机气溶胶粒子的产生, 主要的气相产物表面上发生的后续反应或者非均相反应产物对SOA的生长具有促进作用。

OH-initiated photooxidation reaction of isoprene was performed in the home-made smog chamber. 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 secondary organic aerosol (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, and SOA began to form 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.