De Simone Francesco, Artaxo Paulo, Bencardino Mariantonia, Cinnirella Sergio, Carbone Francesco, D'Amore Francesco, Dommergue Aurélien, Feng Xin Bin, Gencarelli Christian N, Hedgecock Ian M, Landis Matthew S, Sprovieri Francesca, Suzuki Noriuki, Wängberg Ingvar, Pirrone Nicola
CNR-Institute of Atmospheric Pollution Research, Division of Rende, UNICAL-Polifunzionale, 87036 Rende, Italy.
University of Sao Paulo, Sao Paulo, Brazil.
Atmos Chem Phys. 2017;17:1881-1899. doi: 10.5194/acp-17-1881-2017.
Mercury (Hg) emissions from biomass burning (BB) are an important source of atmospheric Hg and a major factor driving the interannual variation of Hg concentrations in the troposphere. The greatest fraction of Hg from BB is released in the form of elemental . However, little is known about the fraction of Hg bound to particulate matter (Hg) released from BB, and the factors controlling this fraction are also uncertain. In light of the aims of the Minamata Convention to reduce intentional Hg use and emissions from anthropogenic activities, the relative importance of Hg emissions from BB will have an increasing impact on Hg deposition fluxes. Hg speciation is one of the most important factors determining the redistribution of Hg in the atmosphere and the geographical distribution of Hg deposition. Using the latest version of the Global Fire Emissions Database (GFEDv4.1s) and the global Hg chemistry transport model, ECHMERIT, the impact of Hg speciation in BB emissions, and the factors which influence speciation, on Hg deposition have been investigated for the year 2013. The role of other uncertainties related to physical and chemical atmospheric processes involving Hg and the influence of model parametrisations were also investigated, since their interactions with Hg speciation are complex. The comparison with atmospheric Hg concentrations observed at two remote sites, Amsterdam Island (AMD) and Manaus (MAN), in the Amazon showed a significant improvement when considering a fraction of Hg from BB. The set of sensitivity runs also showed how the quantity and geographical distribution of Hg emitted from BB has a limited impact on a global scale, although the inclusion of increasing fractions Hg does limit availability to the global atmospheric pool. This reduces the fraction of Hg from BB which deposits to the world's oceans from 71 to 62 %. The impact locally is, however, significant on northern boreal and tropical forests, where fires are frequent, uncontrolled and lead to notable Hg inputs to local ecosystems. In the light of ongoing climatic changes this effect could be potentially be exacerbated in the future.
生物质燃烧（BB）排放的汞（Hg）是大气汞的重要来源，也是驱动对流层汞浓度年际变化的主要因素。生物质燃烧产生的汞中，最大部分以元素汞的形式释放。然而，对于生物质燃烧释放的与颗粒物结合的汞（Hg）的比例，人们了解甚少，而且控制这一比例的因素也不确定。鉴于《水俣公约》旨在减少人为活动中汞的故意使用和排放的目标，生物质燃烧汞排放的相对重要性将对汞沉积通量产生越来越大的影响。汞的形态是决定汞在大气中重新分布以及汞沉积地理分布的最重要因素之一。利用最新版的全球火灾排放数据库（GFEDv4.1s）和全球汞化学传输模型ECHMERIT，研究了2013年生物质燃烧排放中汞形态以及影响形态的因素对汞沉积的影响。还研究了与涉及汞的大气物理和化学过程相关的其他不确定性的作用以及模型参数化的影响，因为它们与汞形态的相互作用很复杂。与在亚马逊地区的两个偏远站点——阿姆斯特丹岛（AMD）和马瑙斯（MAN）观测到的大气汞浓度进行比较，结果表明，考虑生物质燃烧产生的一部分汞时，情况有了显著改善。一系列敏感性试验还表明，尽管增加汞的比例确实会限制全球大气汞库的可用性，但生物质燃烧排放的汞的数量和地理分布在全球范围内的影响有限。这使得从生物质燃烧排放到世界海洋的汞的比例从71%降至62%。然而，在火灾频繁、不受控制且导致当地生态系统有大量汞输入的北方寒带和热带森林地区，局部影响是显著的。鉴于当前的气候变化，这种影响在未来可能会加剧。
