OH Reactivity Measurement and Chemical Analyses of BVOCs Emitted from Sugi (Cryptomeria japonica)

Abstract

O₃ is created by the reaction of OH and trace species in the atmosphere. The reactions are related to the anthropogenic and biogenic VOCs. Biogenic VOCs (BVOC) are measured as well as anthropogenic VOCs, and many kinds of BVOC measurements have been reported. The number of reports of BVOCs emitted from Sugi (Cryptomeria japonica) is limited, because Sugi is an endemic species in Japan. Though Sugi is the major species in Japan, only a few studies have reported BVOC emissions from Sugi. This is first study of Sugi to measure the total OH reactivity based on wild VOC measurements by PTR-MS and GC-FID. In this paper, the enclosure technique was used, and trace species emitted from Sugi was concurrently measured using the total OH reactivity measurement system and chemical analysis. β-farnesene contributed to 15.1% of the total OH reactivity. However 61.2% of the missing OH reactivity was found in this measurement. Even 23 major BVOCs were measured. The OH reaction rate coefficient of the unidentified species in the GC-FID chromatogram was determined. The reaction rate coefficient and OH reactivity of the biggest unidentified peak was determined to be 1.1×10^-10 cm³/molecule s, that was 18.1% of the total OH reactivity. Therefore, 56.9% of the total OH reactivity was identified.