Estimation of Biogenic VOC Emissions in East Asia with New Emission Factors and Leaf Energy Balance Considerations

Estimation of Biogenic VOC Emissions in East Asia with New Emission Factors and Leaf Energy Balance Considerations

A good inventory system of biogenic VOCs emissions in East Asia is required and must function correctly alongsideavailable meteorological data to enable adequate estimation of biogenic emissions. There is a wide body of literature concerningestimations of biogenic emissions in East Asia or larger areas; however, many use environmental temperature rather than leaftemperature; further, they only focus on three kinds of biogenic VOCs: Isoprene, Monoterpenes and other BVOCs. This maycause estimation errors, the size of which are unclear. The purpose of this study is to establish an estimation model of biogenicVOC emissions for East Asia giving due consideration to the leaf energy system, ensuring it can be used effectively withappropriate meteorological data, while estimating hourly emissions of 33 specific species of biogenic VOCs from plants in EastAsia. Estimation errors found using environmental temperature instead of leaf temperature were also investigated. Finally,uncertainty of estimation results was analyzed with regard to land use and emission factor datasets.Total annual BVOC emissions in East Asia (the domain of this study) estimated by the model established by this study canbe up to 40.9 Tg yr-1 and are comprised of 24.6% isoprene, 45.1% of 14 species of monoterpenes, 28.9% of 17 species of otherBVOCs and just 1.4% MBO. The replacement of leaf temperature with environment temperature results in overestimations ofannual amounts for all BVOC species. Results indicated that total BVOC emissions were overestimated by 30.7%, withsignificant overestimations of isoprene, 46.7%, and a smaller but still significant overestimation of monoterpenes of around24.2%. Not all areas exhibited overestimations as zonal and seasonal differences were influential. In summer, when leaf energyinstead of ambient temperature was used, BVOC emissions in all areas of the simulation region were overestimated. In winter,overestimations appeared in areas at lower latitudes, and underestimations appeared in areas at higher latitudes. With regard touncertainty, three different kinds of emission factors and two types of land use data were applied. Results showed that estimatedemissions of BVOCs varied more than 200% when either emission factors or land use data were used. Besides, the dailymaximum O3 concentration changed significantly in some areas (-15–9 ppb). To reduce uncertainty in estimation results, asuitable database of land use and emission factors that gives consideration to vegetation features in different areas is required.