[Historical Trends of Atmospheric Pb and Hg Emissions from Fossil Fuel Combustion in Shanghai]

Rapid urbanization in Shanghai over the past century has led to increased resource and energy consumption, in turn leading to the release of significant amounts of toxic pollutants into the urban environment. In order to investigate historical variations in atmospheric metal emissions from typical combustion sources in Shanghai, historical emissions of Pb and Hg from coal-fired sectors (coal-fired power plant, industrial sector, and domestic use) and vehicle exhaust in Shanghai during the period 1949-2015 were estimated, based on consumption of fossil fuels (coal and gasoline) and emission factors. Results showed that Pb and Hg emissions exhibited rapidly fluctuating increases from 1949 to the 1980s or 1990s, before beginning to decrease sharply due to various pollution control measures. Hg emissions from coal-fired sources played a dominant role during the 1980-2015 period, contributing a high proportion (87.5%-99.7%) to the total. The dominant sources of atmospheric Pb emissions have experienced historical variations. Coal-fired emissions became the major contributor (78.2%-83.5% of total) following omission of leaded gasoline from the Shanghai market since 1997. However, the rapid increase of gasoline consumption since 2005 has led to gasoline-fired emissions again becoming the main contributor (55.5%-79.1%).