China is a world factory powered by its abundant coal resource. China is facing a huge environmental challenge brought together with the fossil-fired power plants. China has therefore been conducting technical retrofit to the engines of its economy, by introducing emission control facilities. Selective Catalytic Reduction (SCR) technology is one of the most widely applied emission control solutions in Chinese power industry. In this case study you can read about Qiangui Panxian Power Plant that had challenges measuring ammonia slip.