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在烟雾箱内研究了温度为(301±2)K时苯乙烯-NOx-air光照体系生成的二次有机气溶胶(SOA).分别探讨了高相对湿度(RH=72%)对SOA的化学组分、数浓度、产率等的影响.通过长光程傅立叶红外(FTIR)得到苯乙烯-NOx光照体系的气相产物主要有甲醛、苯甲醛、甲酸和CO等.采用聚四氟乙烯(PTFE)膜对SOA进行富集,用FTIR对其化学组分进行分析,推得SOA的主要物种有过氧苯甲酸硝酸酯、苯甲酸羟基苯基甲酯和苯甲酸.高相对湿度时气相产物中甲酸量显著提高,同时SOA红外谱图中新增加了苯甲酸,而酯中的羰基吸收峰却比低相对湿度时降低了,从而证实了H2O与Criegee双自由基反应生成苯甲酸的路径,同时也间接地说明了Criegee双自由基与苯甲醛反应生成苯甲酸羟基苯基甲酯的存在.高相对湿度时SOA的数浓度比低相对湿度时降低了约36%～44%,但根据在膜上的SOA质量得到高相对湿度时SOA产率比低相对湿度时提高了约40%,说明高相对湿度增大了SOA的粒子尺度.
The secondary organic aerosols (SOA) generated by the styrene-NO x-air illumination system at a temperature of (301 ± 2) K were studied in a smoke chamber. The effects of high relative humidity (RH = 72% Composition, concentration, yield, etc. The gas phase products of styrene-NOX illumination system are mainly formaldehyde, benzaldehyde, formic acid and CO by long-path Fourier transform infrared spectroscopy (FTIR) ) Membrane enrichment of SOA, FTIR analysis of its chemical composition, deduced that the main species of SOA are benzoate nitrate, benzoic acid hydroxy phenyl methyl ester and benzoic acid.High relative humidity in the gas phase product The amount of formic acid increased significantly. At the same time, benzoic acid was newly added in the infrared spectrum of SOA, while the carbonyl absorption peak in ester was lower than that of low relative humidity, which confirmed the path of benzoic acid generated from diradical reaction between H2O and Criegee But also indirectly shows that the Criegee diradical reacted with benzaldehyde to form hydroxyphenyl benzoate.The number concentration of SOA at high relative humidity is reduced by 36% ~ 44% compared with the low relative humidity, The quality of SOA on SOA gets higher relative humidity with lower SOA yields Humidity increased by about 40%, indicating that high relative humidity increases Particle Size of SOA.