Spatial variation of near-surface CO sub(2) concentration during spring in Shanghai

• Published in: Atmospheric pollution research 2016-01, Vol.7 (1), p.31-39
• Main Authors: Liua, Min, Zhua, Xiyang, Pana, Chen, Chena, Liang, Zhangc, Hao, Jiaa, Wenxiao, Xianga, Weining
• Format: Article
• Language: English
• ISSN: 1309-1042; 1309-1042
• DOI: 10.1016/j.apr.2015.07.002

Urban area plays an important role in global carbon cycle, yet few efforts have been made to investigate CO sub(2) concentration and its spatial heterogeneity in cities. Using Shanghai, the commercial and financial center of mainland China, as a case study, this paper explored the spatial pattern and determinants of near-surface urban CO sub(2) concentration during spring. A total number of 173 sample points were collected covering the whole urban area, to examine the atmospheric CO sub(2) concentration across various land use types (transportation, commercial, agricultural, recreational, institutional, residential and industrial land use) and urbanization gradients (heavy, moderately heavy, medium, moderately low, and low urbanization). CO sub(2) concentrations were measured at a height of 2 m above the ground during 9:00-11:00 am in April and May 2014. The results indicated that CO sub(2) concentration for the region was 409.4 plus or minus 20.8 parts per million (ppm), showing significant spatial heterogeneity. The daytime ambient CO sub(2) concentration varied across land use types (p < 0.05), with the highest and lowest value appeared in transportation area (420.5 plus or minus 33.3 ppm) and agricultural land (398.9 plus or minus 16.2 ppm). Across the urban gradients of Shanghai, a significant decrease of CO sub(2) concentration was observed as the distance from urban core increased. With the influence of both high residential density and activities in production, the highest CO sub(2) concentration occurred in moderate urbanization area (423.9 plus or minus 29.3 ppm), rather than the high urbanization area (417.2 plus or minus 17.5 ppm). Further analysis indicated that the percent of impervious surface cover (ISA) was an important indicator to describe near surface CO sub(2) concentration with a positive correlation, and the percent of vegetation coverage (Veg) had lower explanatory power with a negative correlation. When buffer distance of spatial scale was 2000 m, atmospheric CO sub(2) concentration showed the highest correlation with impervious surface and vegetation coverage.