Satellite measurements oversee China’s sulfur dioxide emission reductions from coal-fired power plants

Abstract

To evaluate the real reductions in sulfur dioxide (SO 2 ) emissions from coal-fired power plants in China, Ozone Monitoring Instrument (OMI) remote sensing SO 2 columns were used to inversely model the SO 2 emission burdens surrounding 26 isolated power plants before and after the effective operation of their flue gas desulfurization (FGD) facilities. An improved two-dimensional Gaussian fitting method was developed to estimate SO 2 burdens under complex background conditions, by using the accurate local background columns and the customized fitting domains for each target source. The OMI-derived SO 2 burdens before effective FGD operation were correlated well with the bottom-up emission estimates (R=0.92), showing the reliability of the OMI-derived SO 2 burdens as a linear indicator of the associated source strength. OMI observations indicated that the average lag time period between installation and effective operation of FGD facilities at these 26 power plants was around 2 years, and no FGD facilities have actually operated before the year 2008. The OMI estimated average SO 2 removal equivalence (56.0%) was substantially lower than the official report (74.6%) for these 26 power plants. Therefore, it has been concluded that the real reductions of SO 2 emissions in China associated with the FGD facilities at coal-fired power plants were considerably diminished in the context of the current weak supervision measures.

Targeted emission reductions from global super-polluting power plant units

“…Our results can be applied not only to prioritize retrofits but to prioritize retirement and replacement of super-polluting power-generating units with non-emitting energy sources. In developing countries such as China, excess emissions were always a problem due to a lack of effective regulation enforcement 23,47 . Strengthened supervision systems should be developed and operated to avoid such undesirable emissions.…”

Predicting decadal trends in cloud droplet number concentration using reanalysis and satellite data

“…Since 2012 SO 2 over eastern China has decreased substantially. This may reflect emission controls implemented as part of the 12 th five-year plan (Tian et al, 2013;Zhao et al, 2013), as well as cleaner coal-fired technology (Wang et al, 2015). The strong decrease in SO 2 from 2012 is mirrored in trends in CDNC over the Pacific.…”

A 15-year record (2001–2015) of the ratio of nitrate to non-sea-salt sulfate in precipitation over East Asia

“…The NO 2 column has been used to capture NO x emissions (e.g., Miyazaki et al, 2012;Mijling et al, 2013;Itahashi et al, 2014b;Han et al, 2015;Irie et al, 2016), and the SO 2 column has been used for SO 2 emissions (e.g., Lee et al, 2011;Li et al, 2010) and/or volcanic eruptions (e.g., Brenot et al, 2014). Several studies have indicated the importance of different technologies to control emissions (e.g., Li et al, 2010;Wang et al, 2015;Krotkov et al, 2016;van der A et al, 2017). For example, the ratio of Ozone Monitoring Instrument (OMI)-derived SO 2 / NO 2 was used to determine the effectiveness of the flue-gas desulfurization devices for power plants in China (Li et al, 2010;Wang et al, 2015).…”

“…Several studies have indicated the importance of different technologies to control emissions (e.g., Li et al, 2010;Wang et al, 2015;Krotkov et al, 2016;van der A et al, 2017). For example, the ratio of Ozone Monitoring Instrument (OMI)-derived SO 2 / NO 2 was used to determine the effectiveness of the flue-gas desulfurization devices for power plants in China (Li et al, 2010;Wang et al, 2015).…”