Three-dimensional spatiotemporal variability of CO2 in suburban and urban areas of Shaoxing City in the Yangtze River Delta, China

Zhentao Wu; Xiaobing Pang; Bo Xing; Gaosheng Zhao; Songhua Sun; Kaibin Yuan; Youhao Lu; Qianqian Sun; Qianqian Shang; Yu Lu; Yan Lyu; Dongzhi Chen

doi:10.1016/j.scitotenv.2023.163501

Three-dimensional spatiotemporal variability of CO₂ in suburban and urban areas of Shaoxing City in the Yangtze River Delta, China

Sci Total Environ. 2023 Jul 10:881:163501. doi: 10.1016/j.scitotenv.2023.163501. Epub 2023 Apr 17.

Authors

Zhentao Wu¹, Xiaobing Pang², Bo Xing³, Gaosheng Zhao⁴, Songhua Sun³, Kaibin Yuan¹, Youhao Lu¹, Qianqian Sun¹, Qianqian Shang¹, Yu Lu¹, Yan Lyu¹, Dongzhi Chen⁵

Affiliations

¹ College of Environment, Zhejiang University of Technology, Hangzhou 310000, China.
² College of Environment, Zhejiang University of Technology, Hangzhou 310000, China. Electronic address: pangxb@zjut.edu.cn.
³ Shaoxing Ecological and Environmental Monitoring Center of Zhejiang Province, Shaoxing 312000, China.
⁴ School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China. Electronic address: zgs571@shu.edu.cn.
⁵ School of Petrochemical Engineering & Environment, Zhejiang Ocean University, Zhoushan 316022, China.

PMID: 37075997
DOI: 10.1016/j.scitotenv.2023.163501

Abstract

Metropolitan areas are the most anthropogenically active places but there is a lack of knowledge in carbon dioxide (CO₂) spatial distribution in suburban and urban areas. In this study, the CO₂ three-dimensional distributions were obtained from 92 times vertical unmanned aerial vehicle (UAV) flight observations in Shaoxing suburbs and 90 times ground mobile observations in Shaoxing urban areas from Nov. 2021 to Nov. 2022. The vertical distribution showed that CO₂ concentrations gradually decreased from 450 to 420 ppm with altitude from 0 to 500 m. CO₂ vertical profile concentrations can be influenced by transport from multiple regions. Based on the vertical observation data combining a potential source contribution function (PSCF) model, Shaoxing suburban CO₂ were to be derived from urban areas in spring and autumn, while in winter and autumn were mainly from the long-transports from neighboring cities. Further the CO₂ concentrations of urban horizontal distribution were observed in the range of 460-510 ppm through the mobile campaigns. Urban CO₂ were partly emitted from traffic exhausts and residential combustion. Overall, CO₂ concentrations were observed to be lower in spring and summer due to the CO₂ uptake by plant photosynthesis. This uptake was initially quantified and accounted for 4.2 % of total CO₂ in suburbs and 3.3 % in urban areas by calculating the decrease in CO₂ concentration from peak to trough in the daytime. Compared with the CO₂ observed in the Lin'an background station, the maximum regional CO₂ enhancement in Shaoxing urban areas reached to 8.9 % while the maximum in suburbs only 4.4 %. The contribution differences between urban and suburban areas to regional CO₂ were relatively constant at 1.6 % in four seasons may be mainly ascribed to the contribution of long-range CO₂ transport to the suburbs.

Keywords: Carbon dioxide; PSCF model; Photosynthesis; Spatial distribution; UAV flight observation.