[Coordinated Control of PM2.5 and O3 in Hangzhou Based on SOA and O3 Formation Potential].

A continuous observation campaign was carried out with the Syntech Spectras GC955 volatile organics online monitoring system from March 1, 2019 to May 31, 2019 in Hangzhou. The constituent features of VOCs, the preferred VOCs species, and VOCs characteristic pollutant ratios were analyzed. The results showed that alkanes were the most important component in the volume fraction of VOCs, accounting for 62.40%. C2-C6 alkanes, benzene series, ethylene, and acetylene were the key species of VOCs. Olefins and aromatics were the main contribution components of OFP, with contribution rates of 41.35% and 37.50%, respectively. Aromatics were the main contributors to SOA, with a contribution rate of more than 90%. Low carbon alkanes, low carbon olefins, and benzene series were the key contributing species of OFP. Controlling toluene, m/p-xylene, and o-xylene is the key to the coordinated control of O3 and PM2.5. VOCs in the atmosphere of the sampling point were not only affected by motor vehicle exhaust but were also significantly affected by industrial emissions, such as solvents.

[Variation Characteristics of Ambient Volatile Organic Compounds (VOCs) Volume Fraction During Hangzhou COVID-19 Period].

A continuous observation campaign was carried out with the Syntech Spectras GC955 volatile organics online monitoring system from December 1, 2019 to March 31, 2020 during the COVID-19 period in Hangzhou. Composition characteristics, diurnal variation, and atmospheric chemical reactivity of VOCs were analyzed. The results showed that φ(total VOCs) were the highest before the COVID-19 pandemic in different sites and the lowest during the first response period. The φ(total VOCs) at night was higher than that during the day. The daily variation in Wolongqiao φ(total VOCs) was less than that in Xiasha. The daily variation in φ(total VOCs) during the first level response period was less than that during the other three periods. The diurnal variation in the φ (total VOCs) in Xiasha showed a "V" shape, and that in Wolongqiao showed a typical bimodal structure. The OFP in Xiasha was higher than that in Wolongqiao. The OFP were the highest at the two sites before the COVID-19 pandemic. The OFP was the lowest during the first response period in Xiasha and the lowest during the second response period in Wolongqiao. The OFP of aromatics and olefins was higher, and the OFP of alkynes was the lowest in Xiasha. The OFP of olefin in Wolongqiao was much higher than that of the other three components, followed by alkane and alkyne.