Black carbon(BC)has a significant impact on air quality and atmospheric light absorption due to its unique physical properties.In this study,a ten-wavelength black carbon monitor was used to measure BC concentrations ...Black carbon(BC)has a significant impact on air quality and atmospheric light absorption due to its unique physical properties.In this study,a ten-wavelength black carbon monitor was used to measure BC concentrations continuously during winter in urban Beijing.A comparison of BC concentrations was carried out between the ten-wavelength black carbon monitor and a multiangle absorption photometer(MAAP)and a thermal optical transmission method carbon analyzer.The results showed significant correlations between BC measured by the MAAP,the thermal optical transmission method carbon analyzer and BC measured at the 660 nm wavelength using the ten-wavelength black carbon monitor.Obvious differences in BC concentrations were recorded at the different wavelength ranges.The BC concentrations observed in the visible ranges,near-infrared ranges and near-ultraviolet ranges were on average 3.1,2.6,and 4.6μg m?3,respectively.The differences between the absorption coefficient of BC370 nm and BC880 nm increased with the enhancement of OC:TC(ratio of organic carbon to total carbon)and PM2.5,indicating that organic matter had strong light absorption at near-ultraviolet wavelength.BC concentrations had clear diurnal variations with maxima at 0300 and minima at 1400(Local time).In addition,potential contribution source areas of BC were also analyzed.This is the first time that BC measurements have been conducted using the ten-wavelength BC monitor,which provided more information of BC at different wavelengths compared to other methods.展开更多
基于Kolmogorov-Zurbenko(KZ)滤波和Robust Extraction of Baseline Signal(REBS)方法处理了青藏高原纳木错站和珠峰站多年连续的近地面臭氧原始观测数据.通过合理选择KZ滤波器和REBS滤波窗口与带宽,成功去除了臭氧时间序列中的短期变动...基于Kolmogorov-Zurbenko(KZ)滤波和Robust Extraction of Baseline Signal(REBS)方法处理了青藏高原纳木错站和珠峰站多年连续的近地面臭氧原始观测数据.通过合理选择KZ滤波器和REBS滤波窗口与带宽,成功去除了臭氧时间序列中的短期变动,提取了代表两站近地面臭氧背景浓度信号.结果表明,KZ滤波法得到的纳木错站和珠峰站臭氧年平均背景浓度分别为89.71μg/m^(3)和88.98μg/m^(3);REBS方法得到的分别为89.62μg/m^(3)和88.52μg/m^(3).两种方法得到的背景臭氧浓度一致性较好,都呈现出相似的季节变化规律.4~5月臭氧浓度较高,而季风期间则较低.KZ滤波更侧重反映长期趋势和季节周期性变化,而REBS在局部污染时段的表现更好.两种非参数统计方法均可有效应用于背景区域臭氧时间序列分析,为监测和防治臭氧污染提供重要依据.展开更多
Measurements of gaseous pollutants （03, NOx, SO2, and CO） were conducted at Dinghushan background station in southern China from January to December 2013. The levels and variations of O3, NOx, SO2, and CO were analy...Measurements of gaseous pollutants （03, NOx, SO2, and CO） were conducted at Dinghushan background station in southern China from January to December 2013. The levels and variations of O3, NOx, SO2, and CO were analyzed and their possible causes discussed. The annual average concentrations of 03, NOx, SO2, and CO were 24.6 ± 23.9, 12.8 ± 10.2, 4.0 ± 4.8, and 348 ± 185 ppbv, respectively. The observed levels of the gaseous pollutants are comparable to those at other background sites in China. The most obvious diurnal variation of 03 was observed in autumn, with minima in the early morning and maxima in the afternoon. The diurnal variations of SO2 showed high values during the day. The diurnal cycles of NOx showed higher values in the morning and lower values during the night. Higher CO concentrations were observed in spring followed by winter, autumn, and summer. Biomass burning, in combination with the transport of regional pollution, is an important source of CO, SO2, and NOx in spring and winter. Backward trajectories were calculated and analyzed together with corresponding pollutant concentrations. The results indicate that air masses passing over polluted areas are responsible for the high concentrations of gaseous pollutants at the Dinghushan background station.展开更多
为了研究重庆市北碚城区大气碳质气溶胶组分的污染特征,于2014年3月~2015年2月采用安德森采样器采集大气颗粒物样品,用DRI Model 2001 A热光碳分析仪测定其中有机碳(OC)和元素碳(EC)的质量浓度.结果表明,北碚城区PM_(2.1)和PM_(9.0)中OC...为了研究重庆市北碚城区大气碳质气溶胶组分的污染特征,于2014年3月~2015年2月采用安德森采样器采集大气颗粒物样品,用DRI Model 2001 A热光碳分析仪测定其中有机碳(OC)和元素碳(EC)的质量浓度.结果表明,北碚城区PM_(2.1)和PM_(9.0)中OC和EC的年平均浓度分别为(16.3±7.6)、(1.8±0.7)和(25.0±9.7)、(3.2±1.3)μg·m-3.在PM_(2.1)中,OC和EC均呈现出冬春季大于夏秋季的季节变化特征,而PM_(9.0)中OC呈现出夏春季大于冬秋季,EC呈现出冬春季大于夏秋季的季节变化特征.对全年OC和EC的粒径进行分析,发现OC在整个粒径上呈现"双峰型"分布,其中细粒子段峰值位于0.43~0.65μm粒径段,粗粒子段峰值位于4.7~5.8μm粒径段;EC呈现出"三峰型"分布,其中细粒子段峰值位于0.43~0.65μm粒径段,粗粒子段峰值位于4.7~5.8μm粒径段,同时2.1~3.3μm粒径段也出现一个明显峰值.对OC和EC进行相关性分析并对PM_(2.1)中的SOC进行估算,发现北碚城区全年SOC浓度为(6.3±5.9)μg·m-3,占全年OC的33.5%±22.6%,且OC和EC显著相关.最后对北碚城区大气气溶胶的污染来源进行分析,发现污染主要来源于汽油车尾气、生物质燃烧和燃煤排放.展开更多
基金supported by the National Key Research and Development Program of China[grant number2016YFC0202701]the Beijing Municipal Science and Technology Project[grant numbers D17110900150000 and Z171100000617002]
文摘Black carbon(BC)has a significant impact on air quality and atmospheric light absorption due to its unique physical properties.In this study,a ten-wavelength black carbon monitor was used to measure BC concentrations continuously during winter in urban Beijing.A comparison of BC concentrations was carried out between the ten-wavelength black carbon monitor and a multiangle absorption photometer(MAAP)and a thermal optical transmission method carbon analyzer.The results showed significant correlations between BC measured by the MAAP,the thermal optical transmission method carbon analyzer and BC measured at the 660 nm wavelength using the ten-wavelength black carbon monitor.Obvious differences in BC concentrations were recorded at the different wavelength ranges.The BC concentrations observed in the visible ranges,near-infrared ranges and near-ultraviolet ranges were on average 3.1,2.6,and 4.6μg m?3,respectively.The differences between the absorption coefficient of BC370 nm and BC880 nm increased with the enhancement of OC:TC(ratio of organic carbon to total carbon)and PM2.5,indicating that organic matter had strong light absorption at near-ultraviolet wavelength.BC concentrations had clear diurnal variations with maxima at 0300 and minima at 1400(Local time).In addition,potential contribution source areas of BC were also analyzed.This is the first time that BC measurements have been conducted using the ten-wavelength BC monitor,which provided more information of BC at different wavelengths compared to other methods.
文摘基于Kolmogorov-Zurbenko(KZ)滤波和Robust Extraction of Baseline Signal(REBS)方法处理了青藏高原纳木错站和珠峰站多年连续的近地面臭氧原始观测数据.通过合理选择KZ滤波器和REBS滤波窗口与带宽,成功去除了臭氧时间序列中的短期变动,提取了代表两站近地面臭氧背景浓度信号.结果表明,KZ滤波法得到的纳木错站和珠峰站臭氧年平均背景浓度分别为89.71μg/m^(3)和88.98μg/m^(3);REBS方法得到的分别为89.62μg/m^(3)和88.52μg/m^(3).两种方法得到的背景臭氧浓度一致性较好,都呈现出相似的季节变化规律.4~5月臭氧浓度较高,而季风期间则较低.KZ滤波更侧重反映长期趋势和季节周期性变化,而REBS在局部污染时段的表现更好.两种非参数统计方法均可有效应用于背景区域臭氧时间序列分析,为监测和防治臭氧污染提供重要依据.
基金supported by Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDA05100100)
文摘Measurements of gaseous pollutants （03, NOx, SO2, and CO） were conducted at Dinghushan background station in southern China from January to December 2013. The levels and variations of O3, NOx, SO2, and CO were analyzed and their possible causes discussed. The annual average concentrations of 03, NOx, SO2, and CO were 24.6 ± 23.9, 12.8 ± 10.2, 4.0 ± 4.8, and 348 ± 185 ppbv, respectively. The observed levels of the gaseous pollutants are comparable to those at other background sites in China. The most obvious diurnal variation of 03 was observed in autumn, with minima in the early morning and maxima in the afternoon. The diurnal variations of SO2 showed high values during the day. The diurnal cycles of NOx showed higher values in the morning and lower values during the night. Higher CO concentrations were observed in spring followed by winter, autumn, and summer. Biomass burning, in combination with the transport of regional pollution, is an important source of CO, SO2, and NOx in spring and winter. Backward trajectories were calculated and analyzed together with corresponding pollutant concentrations. The results indicate that air masses passing over polluted areas are responsible for the high concentrations of gaseous pollutants at the Dinghushan background station.
文摘为了研究重庆市北碚城区大气碳质气溶胶组分的污染特征,于2014年3月~2015年2月采用安德森采样器采集大气颗粒物样品,用DRI Model 2001 A热光碳分析仪测定其中有机碳(OC)和元素碳(EC)的质量浓度.结果表明,北碚城区PM_(2.1)和PM_(9.0)中OC和EC的年平均浓度分别为(16.3±7.6)、(1.8±0.7)和(25.0±9.7)、(3.2±1.3)μg·m-3.在PM_(2.1)中,OC和EC均呈现出冬春季大于夏秋季的季节变化特征,而PM_(9.0)中OC呈现出夏春季大于冬秋季,EC呈现出冬春季大于夏秋季的季节变化特征.对全年OC和EC的粒径进行分析,发现OC在整个粒径上呈现"双峰型"分布,其中细粒子段峰值位于0.43~0.65μm粒径段,粗粒子段峰值位于4.7~5.8μm粒径段;EC呈现出"三峰型"分布,其中细粒子段峰值位于0.43~0.65μm粒径段,粗粒子段峰值位于4.7~5.8μm粒径段,同时2.1~3.3μm粒径段也出现一个明显峰值.对OC和EC进行相关性分析并对PM_(2.1)中的SOC进行估算,发现北碚城区全年SOC浓度为(6.3±5.9)μg·m-3,占全年OC的33.5%±22.6%,且OC和EC显著相关.最后对北碚城区大气气溶胶的污染来源进行分析,发现污染主要来源于汽油车尾气、生物质燃烧和燃煤排放.
