青藏高原牛粪燃烧PM_(2.5)排放因子及组成特征

Emission Factors and Constituent Characteristics of PM_(2.5)from Cow Dung Combustion in Qinghai-Tibet Plateau

牛粪是青藏高原常用的生活燃料,其燃烧排放的大气污染物影响着青藏高原大气环境,该文为获得不同季节、不同海拔牛粪燃烧PM_(2.5)排放因子及组成特征,在林芝市、那曲市、拉萨市林周县开展了牛粪燃烧研究,利用稀释通道法采集牛粪燃烧排放的PM_(2.5),并分析其组成特征。结果表明,春季林芝牛粪燃烧PM_(2.5)排放因子为(6.260±0.870)g/kg、林周为(8.204±2.085)g/kg、那曲为(8.281±0.300)g/kg。夏季林芝牛粪燃烧PM_(2.5)排放因子为(6.426±1.761)g/kg、林周为(7.669±2.005)g/kg、那曲为(11.912±1.741)g/kg;夏季的相对湿度大于春季,在春夏两季林芝与林周的PM_(2.5)排放因子差异较小,而那曲夏季排放因子略大于春季;随着海拔增高,空气中含氧量降低,牛粪燃烧PM_(2.5)排放因子增大。牛粪燃烧PM_(2.5)中碳组分占比为59.7%~77.8%、水溶性无机离子为17.8%~31.4%、金属元素为3.21%~5.09%;牛粪燃烧PM_(2.5)中OC含量随海拔增高而增加,OC/EC范围为31.35~42.16;PM_(2.5)中PO_(4)^(3-)含量远高于其他水溶性无机离子,PO_(4)^(3-)占比为5.34%~10.16%,PO_(4)^(3-)主要来源于磷肥的施用。重构质量与膜采样质量存在显著线性相关,相关系数R^(2)为0.7238~0.9615,质量重构结果表明牛粪燃烧PM_(2.5)主要由有机物、矿物组分、磷酸盐等组成。

Cow dung is the most familiar and commonly used domestic fuel in the Qinghai-Tibet Plateau,and the atmospheric pollutants emitted due to burning cow-dung affect the atmospheric environment of the Qinghai-Tibet Plateau.In this study,in order to aquire the emission factors and constituent characteristics of PM_(2.5) in association with cow-dung combastion in different seasons and at different altitudes,a series of researches were carried out in Linzhi City,Naqu City and Linzhou County of Lahsa City.By use of the dilution channel method PM_(2.5) generated from buring cow-dung was collected and analyzed in terms of constituent.The results showed that in spring PM_(2.5) emission factors of Linzhi,Linzhou and Naqu were(6.260±0.870)g/kg,(8.204±2.085)g/kg and(8.281±0.300)g/kg,respectively,and in summer,the PM_(2.5) emission factors of Linzhi,Linzhou and Naqu were(6.426±1.761)g/kg,(7.669±2.005)g/kg and(11.912±1.741)g/kg,respectively;the relative humidity in summer was higher than that in spring,and the PM_(2.5) emission factors of Linzhi and Linzhou differed not very much in spring and summer,while the emission factors of Naqu in summer were slightly greater than those in spring.With the increase of altitude,atmospheric oxygen content declined,and the PM_(2.5) emission factor went up.As to the PM_(2.5) constituent characteristics of cowdung combastion,the carbon content of PM_(2.5) was in the range of 59.7%~77.8%,water-soluble ions 17.8%~31.4%,and metal elements 3.21%~5.09%;as to organic carbon(OC)and elementary carbon(EC),the content of OC in PM_(2.5) increased with altitude,and the ratio of OC to EC ranged from 31.35 to 42.16;in regard to PO_(4)^(3-)in PM_(2.5),which origenated mainly from the application of phosphate fertilizer,the content of which was much higher than that of other water-soluble ions,and the proportion of PO_(4)^(3-)ranged 5.34%~10.16%.Besides,there was a significant linear correlation between the reconstructed mass and the membrane sampling mass,the correlation coefficient R^(2) ranged 0.7238~0.9615;and the result of reconstructed mass suggeted that the PM_(2.5) derived from cow-dung combustion was mainly composed of organic matter,mineral components and phosphate.