SO2 Emissions in China \u2013 Their Network and Hierarchical Structures

Shaomin Yan,Guang Wu

doi:10.1038/srep46216

Abstract

SO2 emissions lead to various harmful effects on environment and human health. The SO2 emission in China has significant contribution to the global SO2 emission, so it is necessary to employ various methods to study SO2 emissions in China with great details in order to lay the foundation for policymaking to improve environmental conditions in China. Network analysis is used to analyze the SO2 emissions from power generation, industrial, residential and transportation sectors in China for 2008 and 2010, which are recently available from 1744 ground surface monitoring stations. The results show that the SO2 emissions from power generation sector were highly individualized as small-sized clusters, the SO2 emissions from industrial sector underwent an integration process with a large cluster contained 1674 places covering all industrial areas in China, the SO2 emissions from residential sector was not impacted by time, and the SO2 emissions from transportation sector underwent significant integration. Hierarchical structure is obtained by further combining SO2 emissions from all four sectors and is potentially useful to find out similar patterns of SO2 emissions, which can provide information on understanding the mechanisms of SO2 pollution and on designing different environmental measure to combat SO2 emissions.

Highlights

Of various air pollutants, SO2 is extremely important because it can be adsorbed onto the surface of mineral dust and serves as adsorbed sulfite that is oxidized to form sulfate[1]
As the precursor for sulfate and sulfuric acid, which play crucial roles in the nucleation of fine particles[3], the SO2 concentration is always high during new particle formation events[4,5]
The primary anthropogenic source of SO2 emission is burning of coal and heavy oil whose sulfur content is usually higher than coal, and decomposition of Na2SO428

Summary

Introduction

SO2 is extremely important because it can be adsorbed onto the surface of mineral dust and serves as adsorbed sulfite that is oxidized to form sulfate[1]. A long-term study from 1985 to 2000 showed that 1% increase in SO2 emission in East Asia resulted in 1.29% increase in surface aerosol sulfate concentration[6]. Besides its adverse effect on human health, SO2 is harmful to environments[17,18] because sulfate aerosols turn out the major source for the growth of fine particles, which subsequently lead to visibility impairment, acid rain, haze formation and photochemical smog. The concentration of SO2 was about 60–120 ppb during heavy haze episodes in cities in North China[15], the coexistence of NOx from vehicles speeds up the formation of fine particles. Several models have been applied to simulating of SO2 chemistry and transport in East Asia[43,44], whereas overestimation of SO2 concentrations is typical in modeling of sulfate aerosols on a global scale[45]. On the other hand, Beijing Olympic Games in 2008 had a huge impact on the reduction of SO2 emission[48,49]

Methods

Results

Conclusion