Satellite Remote Sensing Of The Sulfur Dioxide And Nitrogen Dioxide Emissions From Coal-fired Power Plants

Coal-fired power plants are the major anthropogenic source of sulfur dioxide (SO2)and nitrogen dioxide (NOx) emissions in China. The control of power plant emissionsplays a key role in achieving China’s control target for SO2and NOxemissions. Both ofthe monitoring of emission sources and the evaluation of the emission reduction are theurgent demands to environmental managements during the "Twelve Five Period”, whichrequestes a large-scale reductions of SO2and NOxemissions in the following several years.This work quantitatively analyzed the coal-fired power plant emissions of SO2and NOxand their trends by satellite remote sensing, providing a new technique for emissionmonitoring and reduction evaluation.First, this study improved three key parameters used in the rechieving algorithm forOMI and SCIAMACHY SO2columns, which includes removal of background residuals,correction of cloud pressure data and calculation of Air Mass Factor. Compared to theoperational OMI and SCIAMACHY SO2column products, the improved satellite retrievalsshows the better performance and the more reliable ability in quantitatively analyzing thechanges of anthropogenic emissions on both local and regional scales. Second, a newemission inverse method of Gaussion fitting the emissions from a single coal-fired powerplant in complex background with satellite data was developed in this study, by fitting thebackground columns and using an asymmetric fitting domain. The inversed SO2and NOxemissions manifested good relationship to the “bottom-up” emissions, suggesting that thismethod can be used to quantitatively evaluate the SO2and NOxemissions from coal-firedpower plants.Based on the improved satellite measurements and the developed emission inversemethod, the SO2and NOxemissions from thirty-eight isolated coal-fired power plants werequantified using OMI observed SO2and NO2columns. The trends of the NO2and SO2columns observed by satellite around these power plants suggested that the flue-gasdesulfurization devices were not in operation in the early stage. The inversed efficiency ofSO2emission reduction was lower than the reported results. This method can be used asindependent evaluation to the efficiency of the flue-gas desulfurization devices incoal-fired power plants, providing a new technique for emission monitoring and reduction evaluation to the major emission sources in China. The trends of SO2and NO2columnsduring2005-2012in China were analyzed using both of the satellite observed andGEOS-Chem modeled columns. Satellite observations suggested that the rapid increases ofNO2and SO2columns during2005-2007are largely contributed by the newly foundedpower plants. The SO2columns decreased fast in the later stage of the “Eleven FivePeriod”, indicating the contributions of the SO2emission reductions from coal-fired powerplants. The satellite remote sensing of the SO2and NOxemissions from coal-fire powerplants established in this study can provide long-period scientific supports for the airquality management and policy-making of emission reduction in China.