Improvements in the operation of SO2 scrubbers in China's coal power plants.

China has deployed the world's largest fleet of sulfur dioxide (SO(2)) scrubbers (flue gas desulfurization systems), and most of them now appear to be operating properly. Although many plant managers avoided using their SO(2) scrubbers in the past, recent evidence, based on a series of field interviews conducted by the author, suggests that managers of coal power plants now have incentives to operate their scrubbers properly. China's new policy incentives since 2007 appear well designed to overcome the hurdle of high operation and maintenance costs of SO(2) scrubbers. Furthermore, it is now far more likely that offenders will be caught and punished. Continuous emission monitoring systems have played a key role in this change of attitudes. Plant inspections have become much more common, facilitated by a significant increase in the number of inspectors and the fact that the 461,000-megawatt SO(2) scrubbers at the end of 2009 were located in only 503 coal power plants, making frequent inspections little constrained by the shortage of inspectors. Because SO(2) is the precursor of sulfate particles believed to cause significant cooling effects on climate, China's SO(2) mitigation may make it more urgent to control the world's greenhouse gas emissions.