Modified regional biogenic VOC emissions with actual ozone stress and integrated land cover information: A case study in Yangtze River Delta, China

Yutong Wang; Yu Zhao; Lei Zhang; Jie Zhang; Yang Liu

doi:10.1016/j.scitotenv.2020.138703

Modified regional biogenic VOC emissions with actual ozone stress and integrated land cover information: A case study in Yangtze River Delta, China

Sci Total Environ. 2020 Jul 20:727:138703. doi: 10.1016/j.scitotenv.2020.138703. Epub 2020 Apr 17.

Authors

Yutong Wang¹, Yu Zhao², Lei Zhang¹, Jie Zhang³, Yang Liu⁴

Affiliations

¹ State Key Laboratory of Pollution Control and Resource Reuse and School of the Environment, Nanjing University, 163 Xianlin Ave., Nanjing, Jiangsu 210023, China.
² State Key Laboratory of Pollution Control and Resource Reuse and School of the Environment, Nanjing University, 163 Xianlin Ave., Nanjing, Jiangsu 210023, China; Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET), Nanjing University of Information Science and Technology, Jiangsu 210044, China. Electronic address: yuzhao@nju.edu.cn.
³ Jiangsu Provincial Academy of Environmental Science, 176 North Jiangdong Rd., Nanjing, Jiangsu 210036, China.
⁴ Department of Environmental Health, Emory University, Rollins School of Public Health, Atlanta, GA 30322, United States.

PMID: 32334230
DOI: 10.1016/j.scitotenv.2020.138703

Abstract

The biogenic volatile organic compounds (BVOCs) emissions are influenced by ambient ozone (O₃) concentrations and vegetation cover. In most studies, however, the interaction between O₃ and plants has not been considered and there are uncertainties in land cover input and emission factors (EFs) in BVOCs emission estimation, particularly at the regional scale. In this study, an O₃ exposure-isoprene (ISOP) response function was developed using meta-analysis, and the EFs of ISOP and land cover inputs were updated by integrating local measurement and investigation data in the Yangtze River Delta (YRD) region. Five different cases were developed to explore the impacts of O₃ and input variables on the BVOCs emissions using the Model of Emissions of Gases and Aerosols from Nature (MEGAN). The impacts of those variables on O₃ simulation were further examined with air quality modeling. We found that the ISOP emissions were restrained in the city cluster along the Yangtze River during the growing season due to their negative feedback to O₃ exposure for deciduous broadleaf forests. The estimation of BVOCs emissions strongly depended on EFs, and the global EFs underestimated the ISOP emissions in July by 37%, mostly in southern YRD. Different land cover datasets with various fractions and spatial distributions of plant function types resulted in a variation of 200-400 Gg in ISOP emissions in July across YRD. Air quality modeling indicated that BVOCs contributed 10%, 12%, and 11% to the 1-h mean, the maximum daily 1-h average, and the maximum daily 8-h average O₃ concentrations, respectively, for July across the YRD region. Due to the NOx restriction, the spatial distribution of BVOCs emissions was inconsistent with that of their contribution to O₃ formation. The O₃ simulation was more sensitive to the changed BVOCs emissions in the area with relatively large contribution of BVOCs to O₃ formation.

Keywords: Air quality; Exposure-response function; Isoprene; MEGAN; Ozone.