南方林区2000~2016年林火释放污染物动态变化研究

以南方林区为研究区域，基于林业统计年鉴和MODIS卫星火点数据，结合相关文献中不同林型各类污染物的排放因子数据，估算2000~2016年间研究区域各省森林生物质燃烧及污染物排放总量，并分析其时空变化情况.结果表明，南方林区森林火灾总体呈先升后降的趋势，林火空间分布较为分散.2000~2016年南方林区森林生物质燃烧总量4.79×10⁴kt.其中，温带常绿针叶林、温带常绿阔叶林、温带落叶阔叶林、热带常绿阔叶林和灌木的燃烧比例分别为65.24%，17.45%，1.55%，1.10%和14.66%.CO、CO₂、NO_x、CH₄、VOCs和PM_2.5等主要污染物的排放总量均值依次为3.73×10³，5.87×10⁴，48.05，347.27，358.54和365.06kt.此外，各类污染物的时空分布差异性明显：福建、广东、广西全省，海南西部，以及江西和湖南南部是各类污染物网格排放高值区；江西和湖北各类污染物的排放呈显著下降，福建NO_x、VOCs和PM_2.5，以及广东CH₄和VOCs下降趋势显著，其余省份各类污染物排放下降但不显著.林火释放污染物占工业粉尘比例呈波动性上升，表明该地区森林火灾对大气环境的影响程度逐渐增加.

Dynamic changes of pollutants released from forest fire in Southern forested region during 2000-2016

We estimated the quantity of biomass burned and total emission of pollutants released from forest fires in Southern Forest region of China during 2000~2016 based on Forestry Statistical Yearbooks, MODIS satellite fire data and emission factors of different forest types from various studies. In addition, the temporal and spatial dynamics of pollutants were also analyzed. The results showed that the occurrence of forest fires in the southern forest area increased firstly and then decreased and dispersedly distributed in space during the study time period. The total amount of forest biomass burned during 2000~2016 was 4.79×10⁴kt. The burning ratios of temperate evergreen coniferous forests, temperate evergreen broad-leaved forests, temperate deciduous broad-leaved forests, tropical evergreen broad-leaved forests and shrubs were 65.24%, 17.45%, 1.55%, 1.10% and 14.66%, respectively. The emissions of CO, CO₂, NO_x, CH₄, VOCs and PM_2.5 were 3.73×10³, 5.87×10⁴, 48.05, 347.27, 358.54 and 365.06kt, respectively. In addition, a significant variation in the spatial and temporal distribution of pollutants existed. Fujian, Guangdong, Guangxi, Western Hainan and the Southern Jiangxi and Hunan were high emission areas of pollutants. The emission of pollutants in Jiangxi and Hubei decreased significantly. A declining trend of NO_x, VOCs and PM_2.5 in Fujian, and CH₄ and VOCs in Guangdong was observed; however, the change in concentration of pollutants in other provinces was not significant. There is an overall increasing trend of the emission ratio of PM_2.5 released from forest fires, indicating an increasing influence of forest fires on local atmospheric condition in Southern forested region of China.