成都温江PM_(2.5)中水溶性有机质和类腐殖质的含量与光谱特性  

Concentrations and spectral characteristics of water-soluble organic matter and of humic-like substances in PM_(2.5) in Wenjiang, Chengdu

作　　者：翟仲溪 罗伊娜 何京蓉 李云翔 李黎 ZHAI Zhongxi;LUO Yina;HE Jingrong;LI Yunxiang;LI Li(Rural Environment Protection Engineering and Technology Center of Sichuan Province,College of Environmental Sciences,Sichuan Agricultural University,Chengdu 611130,Sichuan,China;Zhengzhou Institute of Metrology,Zhengzhou 450000,Henan,China;Chengdu Academy of Environmental Sciences,Chengdu 610031,Sichuan,China)

机构地区：[1]四川农业大学环境学院四川农业大学农村环境保护工程中心,四川成都611130 [2]郑州计量先进技术研究院,河南郑州450000 [3]成都市环境保护科学研究院,四川成都610031

出　　处：《地球化学》2022年第4期424-433,共10页Geochimica

基　　金：生态文明(温江)研究中心科研项目(ECWY2017001)资助。

摘　　要：为探究PM颗粒物中水溶性有机质(WSOM)和类腐殖质(HULIS)的变化特征及其对大气质量的影响,本研究在四川农业大学成都校区采集四季PM样品,用纯水超声提取样品中WSOM,然后用HLB柱萃取WSOM中的HULIS;使用总有机碳分析仪测定提取液和萃取液中水溶性有机碳(WSOC)和类腐殖质碳(HULIS-C)的含量;同时,应用紫外–可见光谱仪对溶液进行全波长扫描。研究结果显示,成都温江PM中WSOC和HULIS-C全年平均质量浓度分别为9.1±5.4 μg/m^(3)(n=40)和4.8±2.3 μg/m^(3)(n=40)。WSOC和HULIS-C均是冬季浓度最高,春秋次之,夏季浓度最低。全年HULIS-C对WSOC的贡献比为(56±14)%(n=40)。HULIS在254 nm、280 nm和365 nm下的吸光系数(SUVA、SUVA和MAE)均分别大于WSOM的SUVA、SUVA和MAE,显示HULIS比WSOM包含更多比例的芳香族结构,具有更高的平均相对分子质量,且HULIS对大气能见度的影响更为显著。利用254 nm和280 nm处的吸光系数对四季PM中HULIS的平均相对分子质量和芳香度进行估算, HULIS全年平均相对分子质量为734±189,芳香度为(19.8±9.0)%。We collected PMsamples at the Chengdu campus of Sichuan Agricultural University, to investigate the water-soluble organic matter(WSOM) and humic-like substances(HULIS), to investigate their variation characteristics and impacts on air quality in the sampling area. WSOM was extracted from the samples with pure water and an ultrasonic cleaner, and HULIS were extracted from WSOM with HLB columns. A total organic carbon analyzer was used to determine water-soluble organic carbon(WSOC) and humic-like substances carbon(HULIS-C)levels in the extracts. WSOM and HULIS solutions were scanned by an ultraviolet-visible spectrometer at full wavelength. The results show that the annual average mass concentrations of WSOC and HULIS-C in PMin Wenjiang District, Chengdu, were 9.1±5.4 μg/m^(3)(n=40) and 4.8±2.3 μg/m^(3)(n=40) during sampling periods,respectively. WSOC and HULIS-C concentrations were highest in winter, followed closely by spring and autumn data, with summer being the lowest. The contribution ratios of HULIS-C to WSOC for the whole year were(56±14)%(n=40). The absorption coefficients(SUVA, SUVA, and MAE) of HULIS were higher than those of WSOM, indicating that, compared with WSOM, HULIS contained a higher fraction of aromatic structures, had a higher average molecular weight, and made more important contributions to visibility. The absorption coefficients at 254 nm and 280 nm were used to estimate the average molecular weights and aromaticity of HULIS in PM.The average molecular weights and aromaticity of HULIS were 734±189 and(19.8±9.0)%, respectively.

关 键 词：水溶性有机质 类腐殖质 光谱特性 

分 类 号：X142[环境科学与工程—环境科学]