Impacts Of Relocation,Development,and West-east Transmission Of Energy And Resource Industry In Western China On SO₂ Emission And Contamination In Northwestern,China

Over the past decades,China has experienced imbalanced development in economy and resource industry between the west and east,featured by faster economic growth in eastern China than that in western China,which leads to increasing gaps in personal income and Gross Domestic Product（GDP）between the two parts of China.To accelerate the economic development in western China,Chinese government has implemented a national strategy for energy safety in the 21st century and the Grand Western Development（GWD）programme since the 2000s.The core of this strategy and the GWD programme is to relocate and develop energy and resource industry in energy abundant western China.Presently,the energy and heavy industries have become central pillars in energy-abundant provinces and autonomous regions collectively referred to as China’s“west”.These two pillar industries provide energy,metal,and chemical products to the highly-developed and populated eastern China through a west-east energy and resource product transmission programme.Concerns are raised about the environmental consequences due to the rapid development in energy and resource industries in northwestern China because this part of China has been the poorest region in the country due to its harsh ecological environment which makes northwestern China uniquely susceptible to atmospheric pollution and greenhouse gases.Low precipitation（¹00-300 mm/year）,barren lands,and scarce vegetation coverage considerably reduce the elimination of atmospheric contaminants and carbon dioxide from the air through precipitation and forest uptake.The environment across northwestern China might be further deteriorated with continuous development in energy and resource industry.Extensive investigations into the associations of air quality with energy use and industrialization in well-developed eastern and southern China have been conducted but little is known about environmental consequences of energy and resource industry development and relocation in northwestern China.The present study aims to fill this knowledge gap by assessing quantitatively the atmospheric emissions and levels of sulfur dioxide as well as its changes embodied in the expansion of energy and resource industry in northwestern China.The results from this study could also provide scientific support to air quality management and emission mitigations in this part of China.In this thesis,firstly,the temporal and spatial distribution and long-term trend of SO₂ vertical column densities（VCD）during 2005-2015 were analyzed based on the Ozone Monitoring Instrument（OMI）satellite remote sensing data.The Mann–Kendall（MK）statistical test was performed to examine the step change in SO₂ VCD across China and major national scale energy industrial bases.The temporal variations in SO₂ emissions and contaminations in different regions were linked with industrial development,SO₂ control measures,and environmental policies.A Gauss fitting inversion method was applied to retrieve SO₂ emissions in two national scale energy bases as point sources of SO₂ in northwestern China derived from the satellite OMI remote sensing.Next,a multi-regional input-output model was employed to estimate provincial production-induced and consumption-induced SO₂ emissions and the transfer of SO₂ emission embodied in the goods and services trade among different regions in China.The focus is on the SO₂ emission embodied in the goods and services in northwestern China and the national west-east energy and resource transmission program.Finally,the impact of SO₂ emission embodied in the goods and services in Northwestern China and the west-east transimission of energy and resource industrial products on the local air quality was quantified using the Weather Research and Forecasting model coupled to Chemistry（WRF-Chem）model.The major findings from this Ph D study are summarized below:1.The highest SO₂ VCD was found in the North China Plain（NCP）,the most heavily SO₂-polluted area in China,including Beijing–Tianjin–Hebei,Shanxi,Shandong,and Henan,followed by Sichuan basin,Yangtze River Delta（YRD）,and Pearl River Delta（PRD）.SO₂ VCD increased from 2005 and reached a peak in 2007,and decreased thereafter.In addition,SO₂ VCD was highest in winter,followed by autumn,spring and summer.2.During 2005-2010,SO₂ VCD in eastern and southern China decreased.SO₂ VCD in the Pearl River Delta（PRD）of southern China exhibited the largest decline during 2005–2015 at a rate of-7%yr^-1,followed by the NCP(-6.7%yr^-1),Sichuan Basin(-6.3%yr^-1),and Yangtze River Delta（YRD）(-6%yr^-1).The Mann–Kendall（MK）test revealed the step change points of declining SO2VCD in 2007–2009 for eastern China.The decreasing SO₂ VCD in eastern and southern China were attributed to the implementation of strict SO₂ emission control measures,such as flue-gas desulfurization（FGD）on coal-fired power plants and heavy industries,relocation and shutdown of those enterprises with heavy pollution,and the slowdown of the growth rate of Chinese economy.However,the northwest regions,except for Shaanxi and Gansu,exhibited an increasing trend from2005 to 2010,particularly in those“hot spots”of SO₂ emissions featured by growing SO₂ VCD in those large-scale energy industry bases in northwestern China.The OMI-measured SO₂ VCD detected two“hot spots”,located in the Energy Golden Triangle（EGT）（Ningxia–Shaanxi–Inner Mongolia）and Midong（Xinjiang）energy industrial bases which displayed an increasing trend of SO₂ VCD with the annual growth rate of 3.4%yr^-1 in the EGT and 1.8%yr^-11 in Midong,in contrast to the widespread declining SO2 emissions in eastern and southern China.The OMI SO₂ VCD-derived SO₂ emissions in the Ningdong Energy Chemical Industrial Base（NECIB）and Midong Energy Industrial Base（MEIB）contributed 25%-66%to the total SO₂ emission in Ningxia and15%-20%in Xinjiang.3.Virtual SO₂ emission embodied in the goods and services trade among different regions across China was 5.7 million tonnes in 2002,8.6 million tonnes in 2007,and 6.9 million tonnes in2010,which accounted for 35.8%,45.4%,and 43.9%to the total SO₂ emission in these three years in China,respectively.Northwestern and southwestern China were the major regions with SO₂outflow,and Beijing-Tianjin,the south coast and YRD were the main regions with SO₂ inflow.The Production and Supply of Electric Power,Heat,Gas,and Water（EHGW）as the largest energy production sector was the largest SO₂ emitter which contributed 44.7%to total SO₂ emission embodied in the goods and services trade among regions in China in 2002 and 49.6%in 2007.In2010,due to the implementation of strict SO₂ control measures in the EHGW sector,mining and heavy industry became the major SO₂ emitters which contributed 55.8%to total SO2 emission embodied in the goods and services trade among regions in China.The northwestern,southwestern,and north seaboard（Heibei province）and central China（Henan）were the major regions with SO₂outflow.Eastern and southern China,including Beijing-Tianjin,the south coast and YRD were the main regions with SO₂ inflow via the consumption of the EHGW,mining,and heavy industry products imporated from northwestern China.4.Virtual SO₂ emission embodied in the interregional goods and services trade in northwestern China was 0.3 million tonnes in 2002,1.4 million tonnes in 2007,and 0.8 million tonnes in 2010,respectively.Since 2007,northwestern China became the largest exporter of SO₂ emission embodied in the interregional goods and services trade.In particular,the amount of SO₂ outflow from the EHGW,mining,and heavy industry accounted for 24.8%of the total SO₂ emission in northwestern China in 2002,44.9%in 2007,and 38.7%in 2010,respectively.In addition,30.7%of SO₂ emission in the EHGW derived by final demand of China in 2002,50.2%in 2007,and 43.3%in 2010,as well as that 23.3%of SO₂ emission in the mining and heavy industry derived by final demand of China in 2002,54.8%in 2007,and 43.9%in 2010 outflowed to other regions,especially that to Beijing-Tianjin,central region,north seaboard,the YRD,and northwestern China.5.Using the emission inventories of SO₂ embodied in the goods and services trade featured significantly by energy product trade,the WRF-Chem model simulations were conducted the discern the potential effect of west-east energy and energy-consuming industrial products on the local environment.Results revealed that the 52.1%of SO₂ atmospheric levels in Yinchuan could be attributed to SO₂ emissions due to energy and energy-consuming products trade via the west-east transmission program,followed by eastern Inner Mongolia in 48.2%,western Inner Mongolia in42.5%,Urumqi in 34.7%,and the downwind region including Shanxi in 9.6%,and Beijing in 2.8%.As the largest sector of SO₂ emissions,the amount of SO₂ emitted from the EHGW contributed the48.2%to SO₂ atmospheric level in western Inner Mongolia,followed by northeastern China（17.9%）,Yinchuan（16.5%）,Urumqi（14.9%）,Shanxi（5.4%）,and Beijing（2.6%）,respectively.