Exploring the Dynamic Spatio-Temporal Correlations between PM2.5 Emissions from Different Sources and Urban Expansion in Beijing-Tianjin-Hebei Region.

Shen Zhao,Yong Xu

doi:10.3390/ijerph18020608

Abstract

Due to rapid urbanization globally more people live in urban areas and, simultaneously, more people are exposed to the threat of environmental pollution. Taking PM2.5 emission data as the intermediate link to explore the correlation between corresponding sectors behind various PM2.5 emission sources and urban expansion in the process of urbanization, and formulating effective policies, have become major issues. In this paper, based on long temporal coverage and high-quality nighttime light data seen from the top of the atmosphere and recently compiled PM2.5 emissions data from different sources (transportation, residential and commercial, industry, energy production, deforestation and wildfire, and agriculture), we built an advanced Bayesian spatio-temporal autoregressive model and a local regression model to quantitatively analyze the correlation between PM2.5 emissions from different sources and urban expansion in the Beijing-Tianjin-Hebei region. Our results suggest that the overall urban expansion in the study area maintained gradual growth from 1995 to 2014, with the fastest growth rate during 2005 to 2010; the urban expansion maintained a significant positive correlation with PM2.5 emissions from transportation, energy production, and industry; different anti-haze policies should be designated according to respective local conditions in Beijing, Tianjin, and Hebei provinces; and during the period of rapid urban expansion (2005–2010), the spatial correlations between PM2.5 emissions from different sources and urban expansion also changed, with the biggest change coming from the PM2.5 emissions from the transport sector.

Highlights

China’s urbanization has resulted in significant achievements in recent decades, with an increasing number and continuously expanding scale of cities [1,2]
We took the Beijing-Tianjin-Hebei region as a whole to explore the relationship between PM2.5 emission and urban expansion
We detected that the endogenous spatio-temporal autoregressive parameters of the data are quite high with narrow 95% confidence intervals, showing that the data has significant spatial correlation and time dependence, in addition to the necessity of spatio-temporal autoregressive statistical modeling

Summary

Introduction

China’s urbanization has resulted in significant achievements in recent decades, with an increasing number and continuously expanding scale of cities [1,2]. The level of urbanization has increased from 17.92% in 1978 to 60.60% in 2019 [3] Behind these achievements, China has become the country with the largest pollutant emissions in the world, resulting in various environmental pollution problems, the deterioration of air quality, which is serious in terms of its impact range and intensity [4,5]. The main reason for the deterioration of air quality in urban areas is pollutant emissions, such as SO2 , NOx , and PM2.5 (particulate matters with an aerodynamic diameter ≤ 2.5 μm) [6,7]. Existing research has found that PM2.5 emission is the main pollutant in haze pollution in. Medical research has proved that PM2.5 pollutants can cause various respiratory diseases and increase the death rate of exposed people by destroying the human immune system [13,14]

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Discussion

Conclusion