Temporal and spatial variation relationship and influence factors on surface urban heat island and ozone pollution in the Yangtze River Delta, China

Yuanyuan Wang; Hongyu Du; Yanqing Xu; Debin Lu; Xiyuan Wang; Zhongyang Guo

doi:10.1016/j.scitotenv.2018.03.050

Temporal and spatial variation relationship and influence factors on surface urban heat island and ozone pollution in the Yangtze River Delta, China

Sci Total Environ. 2018 Aug 1:631-632:921-933. doi: 10.1016/j.scitotenv.2018.03.050. Epub 2018 Mar 16.

Authors

Yuanyuan Wang¹, Hongyu Du², Yanqing Xu³, Debin Lu¹, Xiyuan Wang¹, Zhongyang Guo⁴

Affiliations

¹ Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, Shanghai 200241, China; School of Geographic Sciences, East China Normal University, Shanghai 200241, China.
² Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, East China Normal University, Shanghai 200241, China; Department of Environmental Science, East China Normal University, No. 500, Dongchuan Road, Minhang District, Shanghai, China.
³ Department of Geography and Planning, The University of Toledo, Toledo 43606, United States.
⁴ Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, Shanghai 200241, China; School of Geographic Sciences, East China Normal University, Shanghai 200241, China. Electronic address: zyguo@geo.ecnu.edu.cn.

PMID: 29728003
DOI: 10.1016/j.scitotenv.2018.03.050

Abstract

Urbanization has led to an obvious urban heat island (UHI) effect in the Yangtze River Delta (YRD), China. The ozone (O₃) pollution in the YRD is getting worse. The UHI effect is a key factor that affects the O₃ level. Understanding the influences of the UHI effect on O₃ concentrations is necessary for improving air quality. In this study, the temporal and spatial relationship between UHI and O₃ in the YRD during 2015 was investigated. The influence factors of UHI effect and O₃ are both natural and artificial. Multi-source remote sensing data, which include land cover, land surface temperature (LST), Normalization Difference Vegetation Index (NDVI), and digital elevation model (DEM) data, were used to extract surface landscape elements. The results showed that: (1) the average hourly O₃ concentration was 61.83 μg/m³ (30.92 ppb), the highest value was 105.32 μg/m³ (52.66 ppb) at 15:00 and the O₃ peak was 82.50 μg/m³ (41.25 ppb) in September. The O₃ concentrations and temperature have a similar variation trend both in diurnal and monthly. The O₃ concentrations in coastal stations are higher than those inland. (2) The average daytime UHI intensity was 1.24 °C, and the daytime O₃ concentration was 80.66 μg/m³ (40.33 ppb). There is a positive relationship between UHI and O₃ in the YRD. The relationship in the central developed cities is higher than that in the northern and southern cities. (3) The related factors influencing UHI and O₃ include surface landscape, topography and population. The LST and NDVI are most important among these factors. (4) Due to various geographical backgrounds, the UHI intensities and O₃ concentrations show obvious spatial differences. This study provides a reference with which to better understand the relationship among UHI, O₃ and related factors. Furthermore, the issues of atmospheric and energy transmission in this region deserve further study.

Keywords: Land surface parameters; NO(2); Ozone; Surface urban heat island.