Estimations and uncertainty of biogenic volatile organic compound emission inventory in China for 2008-2018

Accurate biogenic volatile organic compound (BVOC) emission estimations are essential for developing effective air pollution control measures. Chinese BVOC emissions were calculated at a spatial resolution of 36 km × 36 km for 2008-2018 using the Model of Emissions of Gases and Aerosols from Nature. A statistical method was developed to obtain more accurate emission rates based on large numbers of observations from China and other countries. The most detailed and accurate vegetation investigations at high resolutions were used to determine the distributions of leaf biomass and coverage for 82 vegetation species and types. The results show that the national BVOCs emissions in China in 2018 were large, 58.89 Tg, with isoprene, monoterpene, sesquiterpene, and other VOCs accounting for 63.60%, 11.35%, 2.18%, and 22.87% of the emissions, respectively. Broadleaf trees exhibited the largest isoprene and total BVOC emissions. The biogenic emissions and compositions displayed strong seasonal variations, and isoprene was significantly more sensitive to seasonality. The emissions were concentrated in the Greater Khingan Mountain, Changbai Mountain, Qinling Mountain, southeast and southwest forest areas, and Hainan Province because of their larger distributions of broadleaf trees with higher emission potentials. During 2008-2018, BVOC emissions increased by 20.18% at an annual rate of 2.03%, and isoprene exhibited the greatest enhancement of 32.67%, which was primarily due to the increase in leaf biomass. The regions with the largest growth were distributed in the Greater Khingan and Changbai Mountains, and the Sichuan, Hunan, and Hubei Provinces, which was primarily the result of the substantial increase in volumes of trees with higher emission rates. The uncertainty of our estimates was evaluated by comparing the applied basal emission factors, vegetation coverages, meteorological data, and emission algorithms from previous studies, and it was estimated to be approximately -36.5-4.6%.