Effect of urban form on PM2.5 concentrations: A case study in the rapidly urbanizing Yangtze River Delta region of China

Authors: Yu Tao*, College of Land Management, Nanjing Agricultural University, Zhen Zhang, College of Land Management, Nanjing Agricultural University, Weixin Ou, College of Land Management, Nanjing Agricultural University
Topics: Land Use and Land Cover Change, Sustainability Science, China
Keywords: Urban form, PM2.5, Urban expansion, Urban sustainability
Session Type: Paper
Day: 4/6/2019
Start / End Time: 5:00 PM / 6:40 PM
Room: Senate Room, Omni, West
Presentation File: No File Uploaded


In this study, we analyzed the spatio-temporal variations of PM2.5 concentration in the rapidly urbanizing Yangtze River Delta (YRD) region of China during the years 1995–2015 using satellite retrieved data. We also assessed changes in urban form of 70 cities in the YRD region by calculating three landscape metrics: contiguity (urban patchiness), compactness (circularity of the main built-up area), and proximity (average distance from all built-up pixels to the centroid of urban cluster). Then we explored the relationships between urban form metrics and PM2.5 concentration for different-sized cities in the YRD region using the ridge regression model. We observed an overall increasing trend in PM2.5 concentration in the YRD region over the past two decades. The total built-up area in the YRD region also increased dramatically from 9183 km2 in 1995 to 18507 km2 in 2015. The urban form of major cities in the YRD region became less fragmented and more compact during the same period. For small cities with less than one million population, a more fragmented and less compact urban shape was associated with lower PM2.5 concentration. However, urban form does not have a significant effect on PM2.5 concentration for large cities with more than one million population. Instead, PM2.5 concentration was only associated with the proportion of built-up area in large cities. The findings of this research are useful in guiding future urban expansion to reshape the urban form to mitigate PM2.5 pollution for the rapidly urbanizing regions in China and other parts of the world.

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