High-resolution inventory of mercury emissions from biomass burning in China for 2000-2010 and a projection for 2020

Biomass burning is an important contributor of atmospheric mercury emissions. An inventory of mercury emissions from biomass burning with a high resolution and long time span is necessary for mercury transport modeling and emission reduction. In this study, an inventory of mercury emissions from biomass burning in China, with high spatial resolution and decade period (2000-2010), is presented, and the emission in 2020 is projected. Results showed that during 2000-2010, the annual average mercury emission from crop residues burning as fuel in household, crop residues burning as waste in fields, fuelwood burning in households, fuelwood burning for production, forest fires, and grassland fires was 2.30, 0.97, 1.66, 0.49, 0.78, and 0.01 Mg, respectively. The total emission was 6.20 Mg yr^-1, lower than the results of previous studies. The majority of mercury species is in the form of Hg⁰, accounting for 78.9%, followed by Hg^p (15.5%) and Hg²⁺ (5.6%). During 2000-2010, mercury emission from biomass burning decreased from 6.08 Mg in 2000 to 5.12 Mg in 2010. For spatial distribution, the mercury emissions were high in the eastern and central regions of China. Results from scenario analysis showed that mercury emission in 2020 is projected to be 6.18 Mg under the growth condition following the trend in 2005-2010 and 3.00 Mg under the condition of the anticipated new development mode. The results of this inventory study could provide useful information for further assessment of global mercury source attribution and mercury transport modeling. Key Points High-resolution mercury emission inventory from biomass burning is developed Locally measured emission factors are applied Mercury speciation information is involved in the inventory