RESUMO
Recently, China has committed to decommissioning the heavy metal (HM) intensive coal-fired power plants (CFPPs), small units especially, yet a quantitative assessment for the impact on HM emissions remains poorly understood. This study, for the first time, compiles a plant-specific inventory for six HMs (Hg, As, Se, Pb, Cd, and Cr) avoided by CFPPs decommissioned in China during the 12th Five Year Plan period. The reduced HM amounts to 271.58 t (9.19 t Hg, 45.84 t As, 60.76 t Se, 85.30 t Pb, 1.74 t Cd, and 68.75 t Cr), accounting for 12.71% of the total emissions from all China's CFPPs in 2010. Small units which have low boiler efficiency and lack air pollutant control devices are more than tenfold HM-intensive as the large units. The detailed HM emission factors for each CFPP decommissioned in each provincial region are also identified. HM content in the coal consumed is a key parameter to determine their corresponding emission factors, while the capacity of decommissioned coal plants plays a decisive role in the reduced emissions. The high-resolution inventory not only verifies China's progress in alleviating HM pollution, but also provides basis for further investigation into HM relevant environmental and human health impact.
