• 关键词：PM_2.5  有机碳  元素碳  生物质燃烧  三峡库区

• 基金项目：国家自然科学基金面上项目(No.41375123);重庆市科学技术委员会项目(No.cstc2014yykfC20003);中国科学院重点部署项目(No.KJZD-EW-TZ-G06-04);国家环境保护大气复合污染来源与控制重点实验室开放基金(No.SCAPC201310);中国科学院西部行动计划项目(No.KZCX2-XB3-14)

• 彭超
• 1. 中国科学院重庆绿色智能技术研究院, 水库水环境重点实验室, 重庆 400714;2. 重庆工商大学, 重庆 400067

• 翟崇治
• 重庆市环境监测中心, 城市大气环境综合观测与污染防控重庆市重点实验室, 重庆 401147

• 王欢博
• 中国科学院重庆绿色智能技术研究院, 水库水环境重点实验室, 重庆 400714

• 田密
• 中国科学院重庆绿色智能技术研究院, 水库水环境重点实验室, 重庆 400714

• 李红丽
• 中国科学院重庆绿色智能技术研究院, 水库水环境重点实验室, 重庆 400714

• 刘源
• 中国科学院重庆绿色智能技术研究院, 水库水环境重点实验室, 重庆 400714

• 付川
• 重庆三峡学院, 三峡库区水环境演变与污染防治重点实验室, 万州 404100

• 张六一
• 重庆三峡学院, 三峡库区水环境演变与污染防治重点实验室, 万州 404100

• 杨复沫
• 中国科学院重庆绿色智能技术研究院, 水库水环境重点实验室, 重庆 400714

• 摘要：在位于三峡库区腹心的山地城市万州城区采集夏季和冬季PM_2.5样品,采用热光反射法(Thermal Optical Reflection,TOR)测定了PM_2.5中有机碳(OC)和元素碳(EC)的浓度,探讨了其污染特征及来源.结果发现,OC和EC在夏季的平均浓度分别为(7.09±1.86) μg · m^-3和(3.49±0.64) μg · m^-3;冬季分别为(16.82±6.87) μg · m^-3和(6.21±2.06) μg · m^-3,高于夏季,这可能与冬季当地居民生物质燃烧的贡献显著增加有关.冬季OC和EC显著线性相关(r=0.89),表明冬季两者的一次污染来源相近.冬季PM_2.5中总碳(TC)和水溶性K⁺含量的相关性(r=0.88)高于夏季(r=0.69),表明冬季生物质燃烧对碳污染贡献显著.利用OC/EC比值法对二次有机碳(SOC)进行估算,SOC的浓度均值在夏季为(2.17±1.46) μg · m^-3,占OC比例为28.18%±13.85%;冬季为(4.46±3.69) μg · m^-3,占OC的23.13%±12.30%.通过计算PM_2.5中8个碳组分丰度,初步判断机动车尾气排放和生物质燃烧是万州城区碳组分的主要来源.

• Abstract：PM_2.5 samples were collected during summer and winter in Wangzhou, a mountainous city in Three Gorges Reservoir, China. Organic carbon (OC) and elemental carbon (EC) were analyzed by thermal optical reflection (TOR) and investigated for their pollution characteristics and sources. The average concentrations of OC and EC were (7.09±1.86) μg · m^-3 and (3.49±0.64) μg · m^-3 in summer, higher than that in winter of (16.82±6.87) μg · m^-3 and (6.21±2.06) μg · m^-3, respectively. This may be related to biomass burning by local residents. The concentrations of OC in PM_2.5 were significantly correlated with EC in winter (r=0.89), suggesting that they might have similar primary sources. The correlations between TC and K⁺ in PM_2.5 were stronger in winter (r=0.88) than summer (r=0.69), suggesting biomass burning contributed significantly to the carbon pollution. The concentrations of secondary organic carbon (SOC) were estimated by OC/EC ratio method. The average concentration of SOC was (2.17±1.46) μg · m^-3 in summer and (4.46±3.69) μg · m^-3 in winter, contributed 28.18%±13.85% and 23.13%±12.30% to total OC, respectively. By calculating and analyzing the abundances of eight kinds of carbon components in PM_2.5, motor vehicle emissions and biomass burning were indicated to be the major sources of carbon components in Wanzhou.

• Key words：PM_2.5  organic carbon (OC)  elemental carbon (EC)  biomass burning  Three Gorges Reservoir

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