Characteristics and chemical reactivity of biogenic volatile organic compounds from dominant forest species in the Jing-Jin-Ji area, China

Abstract Background: Biogenic volatile organic compounds (BVOCs) play an essential role in tropospheric atmospheric chemical reactions. There are few studies conducted on BVOCs emissions of dominant forest species in the Jing-Jin-Ji area. Based on the field survey, forest resources data and the measured standard emission factors, this paper applies the Guenther model developed in 1993 (G93) to estimate the emissions of BVOCs from several dominant forest species (Platycladus orientalis, Quercus variabilis, Betula platyphylla, Populus tomentosa, Pinus tabuliformis, Robinia pseudoacacia, Ulmus pumila, Salix babylonica and Larix gmelinii) in the Jing-Jin-Ji area in 2017. Then the spatiotemporal emission characteristics and atmospheric chemical reactivity of these species were extensively evaluated. Results: Results showed that the total annual BVOCs emissions were estimated to be 70.8 Gg C·a-1, consisting of 40.5% (28.7 Gg C·a-1) isoprene, 36.0% (25.5 Gg C·a-1) monoterpenes and 23.4% (16.6 Gg C·a-1) other VOCs. The emissions from Platycladus orientalis, Quercus variabilis, Populus tomentosa and Pinus tabulaeformis contributed 56.1%, 41.2%, 36.0% and 31.1%, respectively. In summer and winter, BVOCs emissions from the Jing-Jin-Ji area accounted for 61.9% and 1.8% of the annual total. Up to 28.8% of emissions were detected from Chengde followed by Beijing with 24.9%, mainly distributed in the Taihang Mountains and the Yanshan Mountains. Additionally, the Robinia pseudoacacia, Populus tomentosa, Quercus variabilis, and Pinus tabulaeformis contributed mainly to BVOCs reaction activity. Conclusions: Emissions peaked in summer (June, July, and August) and bottomed out in winter (December, January, and February). Chengde contributed the most, followed by Beijing. Platycladus orientalis, Quercus variabilis, Populus tomentosa, Pinus tabulaeformis and Robinia pseudoacacia represent the primary contributors to BVOCs emissions and atmospheric reactivity, hence the planting of these species should be reduced.