consumption, implying that coal use was the main driving force of NO X growth in
China. However, the correlation was getting weaker after 2012, reflecting the effect
of SCR/SNCR application on NO X control. Moreover, the staged implementation of
emission standards for on-road vehicles was expected to result in slower growth of
NO X emissions than that of vehicle population.
14.3.2 Spatial Patterns of SO 2 and NO 2 VCDs
with Implication of Emission Sources
Figure 14.6 illustrates spatial distribution and its inter-annual variations of SO 2 and
NO 2 VCDs, respectively. Large SO 2 VCDs were found in Eastern China with
intensive industrial activity and in Sichuan Basin (SB) with extremely high sulfur
content in coals. NO 2 pollution was more serious in Eastern China and the Pearl
River Delta (PRD) region in southern China. Besides large coal combustion from
industry, transportation also played an important role in NO X emissions in those
developed regions. Figure 14.6b shows the difference in SO 2 VCDs between 2005
and 2012. SO 2 were clearly reduced in highly polluted regions including south
Beijing-Tianjin-Hebi (BTH), central Yangtze River Delta (YRD), and PRD regions,
resulting mainly from the emission control on power sector. The regions with
reduced SO 2 VCDs agreed well with the locations of big power plants. Clearer
reduction in SO 2 VCDs was detected in relatively polluted regions for 2012–2014
(Fig. 14.6c), implying the benefit of increased use of FGD operations for power and
iron and steel sectors along with the implementation of tightened emission standards.
The NO 2 VCDs were found to increase during 2005–2012 in most part of Eastern
China but to decrease in Shanghai and the PRD region (Fig. 14.6e). After 2012, NO 2
VCDs were detected to decline in polluted regions, suggesting the effectiveness of
NO X control in those regions. Combining Fig. 14.6b, e, and f, it can be found that the
SO 2 abatement in heavy polluted Eastern China was earlier than NO 2 , resulting from
the differences in schedule and actions of emission controls in the country during the
11th and 12th FYP periods. The earlier application of FGD than SCR/SNCR
technology in the power sector reduced the SO 2 emissions in Eastern China, while
NO X kept growing before 2010.
The changes in emissions from power plants due to enhanced control could also
be detected by satellite. Li et al. (2010) applied summertime PBL SO 2 VCDs and
evaluated the changes in emissions from 2005 to 2008 in Inner Mongolia, where a
great number of power plants became operational during the period. As illustrated in
Fig. 14.7, the SO 2 VCDs were observed to increase from 2005 to 2007, reflecting the
elevated power generation in the region. However, much smaller SO 2 VCDs was
found in 2008 over eastern, central, and western Inner Mongolia compared to
previous years, attributed largely to the improved control of SO 2 emissions from
power sector.
To improve air quality in developed urban areas, some plants for selected
industrial sectors with relatively high emissions have been moved out from urban
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Y. Zhao and Y. Xia
China. However, the correlation was getting weaker after 2012, reflecting the effect
of SCR/SNCR application on NO X control. Moreover, the staged implementation of
emission standards for on-road vehicles was expected to result in slower growth of
NO X emissions than that of vehicle population.
14.3.2 Spatial Patterns of SO 2 and NO 2 VCDs
with Implication of Emission Sources
Figure 14.6 illustrates spatial distribution and its inter-annual variations of SO 2 and
NO 2 VCDs, respectively. Large SO 2 VCDs were found in Eastern China with
intensive industrial activity and in Sichuan Basin (SB) with extremely high sulfur
content in coals. NO 2 pollution was more serious in Eastern China and the Pearl
River Delta (PRD) region in southern China. Besides large coal combustion from
industry, transportation also played an important role in NO X emissions in those
developed regions. Figure 14.6b shows the difference in SO 2 VCDs between 2005
and 2012. SO 2 were clearly reduced in highly polluted regions including south
Beijing-Tianjin-Hebi (BTH), central Yangtze River Delta (YRD), and PRD regions,
resulting mainly from the emission control on power sector. The regions with
reduced SO 2 VCDs agreed well with the locations of big power plants. Clearer
reduction in SO 2 VCDs was detected in relatively polluted regions for 2012–2014
(Fig. 14.6c), implying the benefit of increased use of FGD operations for power and
iron and steel sectors along with the implementation of tightened emission standards.
The NO 2 VCDs were found to increase during 2005–2012 in most part of Eastern
China but to decrease in Shanghai and the PRD region (Fig. 14.6e). After 2012, NO 2
VCDs were detected to decline in polluted regions, suggesting the effectiveness of
NO X control in those regions. Combining Fig. 14.6b, e, and f, it can be found that the
SO 2 abatement in heavy polluted Eastern China was earlier than NO 2 , resulting from
the differences in schedule and actions of emission controls in the country during the
11th and 12th FYP periods. The earlier application of FGD than SCR/SNCR
technology in the power sector reduced the SO 2 emissions in Eastern China, while
NO X kept growing before 2010.
The changes in emissions from power plants due to enhanced control could also
be detected by satellite. Li et al. (2010) applied summertime PBL SO 2 VCDs and
evaluated the changes in emissions from 2005 to 2008 in Inner Mongolia, where a
great number of power plants became operational during the period. As illustrated in
Fig. 14.7, the SO 2 VCDs were observed to increase from 2005 to 2007, reflecting the
elevated power generation in the region. However, much smaller SO 2 VCDs was
found in 2008 over eastern, central, and western Inner Mongolia compared to
previous years, attributed largely to the improved control of SO 2 emissions from
power sector.
To improve air quality in developed urban areas, some plants for selected
industrial sectors with relatively high emissions have been moved out from urban
324
Y. Zhao and Y. Xia