采用元素示踪技术提高黑碳排放清单的准确性和时效性

黑碳(BC)减排最近被列入全球气候减缓行动的最有效手段之一，同时还有改善空气质量和人类健康、提高农作物产量和保护极地冰盖等多重利益。然而，现有的黑碳排放清单均是基于排放因子的"自下而上"的方法，其中的生物质燃烧部分由于原料的多样性和燃烧的开放性，很难直接测得令人信服的排放因子和估算生物质燃烧量，因而成为黑碳排放清单中最不确定的类别。本项目拟引入元素示踪手段(K/BC比值和黑碳中碳同位素丰度)，通过测定黑碳中的C-14确立生物质燃烧对黑碳总量的贡献份额，通过监测K/BC变化掌握生物质燃烧的时间分布，从而为建立更加科学和更具时效性的黑碳排放清单创造条件。项目的完成，不仅可以提高黑碳地球化学过程的认识，丰富黑碳排放清单创建方法的理论和实践，还为我国参加《后京都议定书》国际谈判提供基础性的研究成果和数据支撑，并为评估我国的黑碳减排效果提供新型和实用的思路和依据。

Black carbon (BC) reduction has recently been chosen as one of the global fast-actions for climate mitigation, which is also conducive to the improvement in air quality and human health, increase of crop production and protection of polar ice-cap. However, currently available BC emission inventories are usually in bottom-up type. That is, they are based on BC emission factors and fuel amounts used, both of which are highly uncerntain due to the diversity of biomass species and the uncontrolability of combustion process. A novel idea is proposed here, aimed to facilitate constructing a more accurate, more reliable and more timely BC emission inventory by introduction of two elemental tracing techniques (the differences in K/BC ratio and carbon isotope between fossil fuels and biomass). The fraction of BC contributed by biomass burning can be duduced through the measurement of C-14 abundance in BC, and the variation of biomass burning can be observed via the measurement of K/BC ratio. The completion of this work can not only deepen the understanding of BC geochemical process, enrich the theory and practice for the development of new type BC emission inventories, but also provide China with basic support for international negotiation on Post-Kyoto mitigation actions. Moreover, new and pragmatic conception and clues can be inferred from this work for assessment of futher BC reduction.