光照对柠檬烯臭氧氧化产生二次有机气溶胶的影响

Effect of Illumination on Secondary Organic Aerosol Formation from Ozonolysis of Limonene

作为一种重要的生物源挥发性有机物,柠檬烯的臭氧氧化是大气环境中二次有机气溶胶(SOA)的重要来源之一。基于实验室烟雾箱模拟系统,研究了紫外光照对柠檬烯臭氧氧化形成SOA的影响。实验分别对无光照(即"暗反应")和有光照条件下反应前体物的消耗、SOA的质量浓度以及SOA的粒径分布随时间的变化等进行了实时探测,并结合气粒分配模型对产率进行了分析。研究结果表明在相应的实验条件下,紫外光照会导致SOA产率下降10%～16%,而气相氧化阶段相关中间产物或者最终产物的光化学反应可能是导致产率下降的重要原因之一。

As an important biogenic volatile organic compound, ozonolysis of limonene is a significant source of atmospheric secondary organic aerosol （SOA）. Quantitative research on ozonolysis of limonene was reported under both dark and UV-illuminated conditions in the self-made smog chamber. The time evolutions of limonene precursor, SOA mass concentration as well as SOA particle size distributions were investigated continuously, and the yield of SOA was analyzed according to the gas/particle partitioning theory. It is shown that exposure to UV light reduces SOA yield by 10%-16% under corresponding conditions, and it is proposed that gas-phase photolysis of some intermediate or final products may play a key role in the decline of yields in the presence of UV light.