SIFT-MS를 이용한 부산시 대기 중 휘발성유기화합물의 오존생성기여도 산정

Abstract

Diurnal variation of ozone and volatile organic compounds (VOCs) were monitored at representative urban and harbor sites in Busan during January and April 2019. A mobile laboratory equipped with selected ion flow tube mass spectrometry (SIFT-MS), cavity ring-down spectroscopy (CRDS), and ozone analyzer was used for close proximity measurement of region-specific sources. Field measurement method of VOCs by SIFT-MS was verified using tiered approach. Fifty-three kinds of VOCs including alkane, alkene, aromatic, alcohol, carboxylic acid, aldehyde, ketone and halogenated compounds were measured in this study. Carbon dioxide well reflected diurnal variation of car exhaust and showed good correlation with ozone concentration, implying that CO2 can be a good tracer for local fossil fuel combustion and ozone contamination. Urban and harbor sites showed different VOCs characteristics, mainly affected by gasoline and heavy-duty diesel vehicle exhaust, respectively. Ozone formation potential (OFP) of VOCs was analyzed by group, in which carbonyl compounds including aldehyde, ketone and carboxylic acid accounted for more than 60 and 70% of OFP at urban and harbor site, respectively. Ozone production per concentration index (OPCI) was proposed to calculate relative contribution of individual compound’s OFP to concentration. Formaldehyde showed the highest OPCI, followed by acrylic acid, aromatic compounds. This study mainly focused on method development of realtime field measurement of VOCs and their contribution to ozone formation, which is expected to provide methodological basis for observation based model study of photochemical reaction of VOCs.