A city-level inventory for atmospheric mercury emissions from coal combustion in China

Abstract

Cities are essential entities for dedicated mercury control policies. However, the city-level mercury emission inventory as the cornerstone of proper policy design is still in its infancy, due to data availability. For the first time, this study developed a comprehensive city-level atmospheric mercury emission inventory from coal combustion in China in 2010, by updating emission factors based on high-resolution information such as the plant-specific air pollution control devices (APCDs) in 182 cities. The estimated atmospheric mercury emissions from coal combustion were 202.3 tons (−51.7%,133.6%), over half of which were concentrated in 36 cities such as Chongqing (megacity) and Ordos (heavily coal-reliant city), implying mercury emissions were unevenly distributed. Mercury emitted from coal-fired power plants with the largest coal consumption was less than that from industrial coal combustion, because more efficient APCDs were installed in power plants. This study also took GDP, the proportion of coal in energy mix and cities’ population as the benchmark to classify cities into various groups. Energy production and heavy manufacturing cities had comparatively larger emissions. Moreover, optional mitigation policies were elaborated for specific cities, such as retrofit of APCDs for coal-reliant cities (e g., Nanyang and Sanmenxia) lack of enough efficient end-of-pipe mercury removal devices.