天然和人为排放VOCs氧化过程关键因子及其对大气光化学过程影响研究

作为臭氧生成前体物之一的VOCs主要有人为源和天然源，天然源的标志性物质是植物排放的异戊二烯，人为源则是以苯系物为代表的机动车排放为主，大气中的VOCs对大气光化学过程的影响主要是通过其一系列的氧化过程，因此，对其氧化过程中的一些关键中间物质进行测量研究对了解VOCs的氧化过程具有重要意义。为了研究不同排放源VOCs的氧化过程对大气光化学过程和臭氧生成的贡献，本项目聚焦VOCs氧化过程的中间产物甲醛和乙二醛，利用差分光学吸收光谱分析技术，对异戊二烯和苯系物，以及甲醛、乙二醛、臭氧和NOx等进行高时间分辨率观测，重点分析乙二醛和甲醛的比值RGF与异戊二烯和苯系物之间关系，研究不同NOx浓度环境下RGF在确定VOCs不同来源过程中的作用，建立RGF与臭氧和NOx之间的矩阵关系，探索以RGF作为示踪因子研究VOCs的氧化过程对臭氧形成的影响机理，进而了解城市臭氧污染过程中臭氧浓度的快速增的原因

As one of the precursors of ozone formation, VOCs mainly comes from man-made and natural emission. The landmark substance of natural sources is isoprene emitted by plants, while anthropogenic sources are mainly motor vehicle emissions represented by aromatics. The influence of VOCs on atmospheric photochemical process is mainly exerted through a series of oxidation processes. Therefore, it is very important to study the key factors in the oxidation process, and the measurement of intermediates is of great significance for understanding the oxidation process of VOCs. In order to study the contribution of VOCs oxidation process from different emission sources to atmospheric photochemistry and ozone formation, this project focused on formaldehyde and glyoxal, the intermediate products of VOCs oxidation process, and used differential optical absorption spectroscopy to observe isoprene and aromatics, formaldehyde, glyoxal, ozone and NOx with high time resolution. The ratio of glyoxal to formaldehyde(RGF) and the relationship between RGF and isoprene and aromatics will be studied. The role of RGF in determining different sources of VOCs under different NOx concentrations will be analyzed, and the matrix relationship between RGF, ozone and NOx will be established in the project. The mechanism of ozone formation should be studied by using RGF as a tracer, in order to understand the reasons for the rapid increase of ozone concentration in urban ozone pollution scenario.