定量评估南亚和东南亚生物质燃烧排放对我国西南部大气环境的影响

The cross - regional transport of air pollutants has been widely concerned by environmental research. South Asia and Southeast Asia are main sources of biomass burning pollutants in the world. Under the influence of westerly circulation and southwest monsoon, the southwest region of China, with its downwind direction, bears the brunt. From the perspective of global change and atmospheric chemistry, this study will take southwest China as study region for collecting aerosol samples for normal and intensive monitoring with various methods including field experiment, data analysis and numerical simulation and research tools such as field research and remote sensing. Through the analysis of the characteristics of physical and chemical properties , the spatial and temporal distribution and sources of biomass burning tracers, the biomass burning combustion on particle concentration in Southwest China is investigated; combing component characteristics and WRF-Chem, transmission ways and mechanism of southwest monsoon and westerly circulations with biomass burning emissions in South and Southeast Asia and contributions of biomass burning emissions from different regional and overseas on Southwest China were studied, so as to access the impact, degree and law of foreign biomass combustion pollutants influences on China's atmospheric environment. It will provides a scientific basis for the protection of atmospheric environment and economic development in the southwest of China, and provides the power of discourse for the national environmental diplomacy.

大气污染物跨区域传输一直是广受关注的环境问题。南亚和东南亚为全球主要的生物质燃烧污染物排放源，在西风环流和西南季风的影响下，位于其下风向的我国西南地区首当其冲。本研究在我国西南部选择代表性区域，进行常规和加强期气溶胶样品采集，通过分析其中生物质燃烧排放标志物的物理化学性质、时空分布及来源特征，从全球变化和大气化学的研究角度，应用数据分析和模式模拟等研究方法，结合地面观测和卫星遥感等研究手段，研究境外生物质燃烧源对我国西南部颗粒物浓度的贡献；结合组分特征，利用WRF-Chem，研究南亚和东南亚生物质燃烧排放在西风环流和西南季风影响下的传输途径和机制，以及境外不同区域生物质燃烧排放对我国西南地区大气环境的贡献，从而获取境外生物质燃烧污染物对我国大气环境的影响方式、程度和规律，为我国西南部大气环境保护和经济发展提供科学依据，为国家环境外交提供话语权。

东南亚和南亚生物质燃烧是全球重要的大气污染物排放源，其排放的污染物对我国西南部空气质量有明显的影响，对该影响的定量评估对我国西南部空气污染治理和我国环境外交有重要作用。现场测定了我国西南部代表区域生物质燃烧排放中PM2.5、NOx、SO2和VOCs等主要大气污染物排放因子，发现云南省NOx排放因子较高，SO2排放因子较低。计算了云南省本地生物质燃烧主要污染物年排放量为：CO2 2248.79万吨、NOx 131.33万吨、SO2 207.94万吨、OC 798.80万吨、EC 218.52万吨和PM2.5 1677.91万吨，建立了云南省生物质燃烧本地排放清单。分析了云南省空气质量变化特征，发现其3至4月PM2.5月均浓度分别高出其他月份均值约1.8倍，污染时段与东南亚和南亚生物质燃烧排放高度相关，位于云南南部区域PM2.5浓度与南亚和东南亚火点数相关性大于0.6，明显优于北部区域的0.4左右，这与CALIPSO卫星激光雷达观测数据基本吻合，表明东南亚和南亚生物质燃烧污染物排放可跨境输送并影响我国西南地区，与后向轨迹分析结果一致。利用滤膜样品采集和在线颗粒物组分浓度观测数据，结果模型分析，发现东南亚缅甸北部和中缅边境的与生物质燃烧相关的二次BrC是青藏高原东南缘BrC的重要来源，超过90%，来自南亚印度北部的污染物对青藏高原西南部一次生物气溶胶贡献约为39%，恒河平原人为排放贡献为5%-20%。