中国露天生物质燃烧的温室气体排放及秸秆禁燃政策的协同减排效应

Greenhouse gas emissions from open biomass burning and the co-reduction due to straw burning bans in China

露天生物质燃烧是温室气体(CO_(2)、CH_(4)、N_(2)O)的重要排放源之一,这些排放可影响本地、区域和全球的大气化学和气候变化,并带来一系列生态环境问题,进而对人类及其他生物的生存环境产生影响.本研究采用卫星火点排放清单(FINN),对2010-2019年中国露天生物质燃烧温室气体排放进行研究,并分析秸秆禁燃政策对温室气体排放的影响,对后续秸秆禁燃政策的制定具有重要参考价值.结果表明,我国2010-2019年平均年温室气体排放量为1.53×10^(8) t(将CH_(4)和N_(2)O的温室效应换算为同等效应的CO_(2)当量单位),总体呈波动性下降趋势.温室气体排放量最大的植被类型是森林(7.43×10^(7) t)和农作物(3.19×10^(7) t),分别占总排放量的48.7%和20.9%.从月分布来看,露天生物质燃烧排放的温室气体集中在2-6月,3月是高峰值.从空间分布上看,排放主要集中在华南、西南和华东地区,占总排放量的72.9%.从2013年以来,秸秆禁燃政策的加强在一定程度上降低了露天农作物秸秆燃烧排放的温室气体和PM_(2.5).从变化量看,28个省份实现了秸秆燃烧排放的温室气体与PM_(2.5)同步下降.

Open biomass burning represents an important emission source of greenhouse gases(CO_(2),CH_(4),N_(2)O,).These emissions affect local,regional and global atmospheric chemistry and climate change,and pose a threat to human health and the environment.This study uses the fire inventory from NCAR(FINN)to investigate the greenhouse gas emissions from open biomass burning in China from 2010 to 2019 and analyzes the impact of straw burning bans on greenhouse gas emissions.Results show that the average annual greenhouse gas emissions due to open biomass burning are 1.53×10^(8) t(the greenhouse effects of CH_(4) and N_(2)O are converted into CO_(2) equivalent units of the same effect)from 2010 to 2019 with a fluctuated downward trend.Greenhouse gas emissions from burning of forests(7.43×10^(7) t)and crops(3.19×10^(7) t)account for 48.7% and 20.9% of the total emissions,respectively.In terms of the monthly variations,highest greenhouse gas emissions due to open biomass burning are during February to June,with peak in March.In terms of the spatial distribution,emissions are mainly concentrated in South China,Southwest China and East China,together accounting for 72.9% of the total emissions.Since 2013,strengthening of the straw burning bans resulted in reduction of PM_(2.5) and the greenhouse gas emissions from open crop straw burning.Emissions of greenhouse gases and PM_(2.5) in 28 provinces decreased simultaneously as the result of the straw burning bans.