Characteristics of VOCs and their Potentials for O3 and SOA Formation in a Medium-sized City in Eastern China

Abstract

To understand the characteristics and environmental effects of volatile organic compounds (VOCs) in a typical medium-sized city in China, manual measurements including 56 species of the nonmethane hydrocarbons (NMHCs) were taken at three urban and suburban sites in Huai'an from April to September 2019, and automatic measurements including 106 species of VOCs were taken at the urban center in May and August 2019. Spatial and temporal characteristics of the VOC concentrations were analyzed. Positive matrix factorization (PMF) model was applied to apportion VOC sources. Ozone (O3) formation potentials (OFPs) and secondary organic aerosol (SOA) formation potentials (SOAFPs) were calculated. The results show that the mean VOC concentration was much lower in the urban center than in the suburbs. Generally, proportions of both alkenes and aromatic hydrocarbons were higher and proportion of alkanes was lower in Huai'an than that in big cities, indicating emissions from solvent usage and industrial process play a more important role in the medium-sized city. The results of source apportionment show that solvent usage and industrial process together contributed 53%, and vehicle emission contributed 27% to the ambient VOCs. The dependence of VOC concentrations on temperature indicates that a considerable part of VOCs may come from fugitive emissions. The two-peak pattern of diurnal variation suggests near-surface emissions contributed a lot to the VOCs. Aromatic hydrocarbons were identified as the key component to the formation of O3 and SOA. Furthermore, biogenic emission could contribute greatly (>20%) to the ambient VOCs during daytime in summer, which may have significant effects on O3 formation. Aromatic hydrocarbons were identified as the key component to the formation of O3 and SOA, which should be given more attention in developing air pollution control strategies.

Composition and Reactivity of Volatile Organic Compounds and the Implications for Ozone Formation in the North China Plain

“…In winter, the daily variation of the same group of VOCs is similar, but its peaks occur about two hours later than those in summer. This pattern has also been observed in other areas [27]. This phenomenon is influenced by local traffic emissions and planetary boundary layer height changes.…”

Chemical Characteristics and Source-Specific Health Risks of the Volatile Organic Compounds in Urban Nanjing, China

“…In this study, the VOCs' MIR values were adopted from those documented in Carter [50], and are available for most VOCs (93 out of 108). Similar to OFP, SOAFP quantifies the ability of a VOC to generate SOA [51][52][53], which is shown in the following equation (details in Hui et al [54]):…”

Research progresses on VOCs emission investigationsviasurface and satellite observations in China

“…a 22, 81 and 82.b 17, 28, 68, 72, 76 and 83–89.c 7.d 2, 4, 14, 16, 18, 19, 21, 29–31, 35, 48, 49, 58, 70, 73, 75 and 90–109.e 71 and 109–111.f 1, 14, 15, 22, 30, 31, 35, 37, 65, 93, 95, 107, 112–115 and 115–118.g 35.h 17, 37, 74, 116 and 119–121.i 122 and 123.j 13, 20, 23, 32–34, 51, 57, 94, 123–127, 127–129 and 129–134.k 123.l 26 and 135–137.m 23, 25, 26, 119…”