Vertical structures of PM10 and PM 2.5 and their dynamical character in low atmosphere in Beijing urban areas     

DING Guoan  CHAN Chuenyu  GAO Zhiqiu  YAO Wenqing  LI Yoksheung  CHENG Xinghong  MENG Zhaoyang  YU Haiqing  WONG Kamhang  WANG Shufeng  MIAO Qiuju 《中国科学D辑(英文版)》2005,48(Z2)

The vertical structures and their dynamical character of PM2.5 and PM10 over Beijing urban areas are revealed using the 1 min mean continuous mass concentration data of PM2.5 and PM10 at 8, 100, and 320 m heights of the meteorological observation tower of 325 m at Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP CAS tower hereafter) on 10―26 August, 2003, as well as the daily mean mass concentration data of PM2.5 and PM10 and the continuous data of CO and NO2 at 8, 100 (low layer), 200 (middle layer), and 320 m (high layer) heights, in combination with the same period meteorological field observation data of the meteorological tower. The vertical distributions of aerosols observed on IAP CAS tower in Beijing can be roughly divided into two patterns: gradually and rapidly decreasing patterns, I.e. The vertical distribution of aerosols in calm weather or on pollution day belongs to the gradually decreasing pattern, while one on clean day or weak cold air day belongs to the rapidly decreasing pattern. The vertical distributive characters of aerosols were closely related with the dynamical/thermal structure and turbulence character of the atmosphere boundary layer. On the clean day, the low layer PM2.5 and PM10 concentrations were close to those at 8 m height, while the concentrations rapidly decreased at the high layer, and their values were only one half of those at 8 m, especially, the concentration of PM2.5 dropped even more. On the clean day, there existed stronger turbulence below 150 m, aerosols were well mixed, but blocked by the more stronger inversion layer aloft, and meanwhile, at various heights, especially in the high layer, the horizontal wind speed was larger, resulting in the rapid decrease of aerosol concentration, I.e. Resulting in the obvious vertical difference of aerosol concentrations between the low and high layers. On the pollution day, the concentrations of PM2.5 and PM10 at the low, middle, and high layers dropped successively by, on average, about 10% for each layer in comparison with those at 8 m height. On pollution days, in company with the low wind speed, there existed two shallow inversion layers in the boundary layer, but aerosols might be, to some extent, mixed below the inversion layer, therefore, on the pollution day the concentrations of PM2.5 and PM10 dropped with height slowly; and the observational results also show that the concentrations at 320 m height were obviously high under SW and SE winds, but at other heights, the concentrations were not correlated with wind directions. The computational results of footprint analysis suggest that this was due to the fact that the 320 m height was impacted by the pollutants transfer of southerly flow from the southern peripheral heavier polluted areas, such as Baoding, and Shijiazhuang of Hebei Province, Tianjin, and Shandong Province, etc., while the low layer was only affected by Beijing's local pollution source. The computational results of power spectra and periods preliminarily reveal that under the condition of calm weather, the periods of PM10 concentration at various heights of the tower were on the order of minutes, while in cases of larger wind speed, the concentrations of PM2.5 and PM10 at 320 m height not only had the short periods of minute-order, but also the longer periods of hour order. Consistent with the conclusion previously drawn by Ding et al., that air pollutants at different heights and at different sites in Beijing had the character of "in-phase" variation, was also observed for the diurnal variation and mean diurnal variation of PM2.5 and PM10 at various heights of the tower in this experiment, again confirming the "in-phase" temporal/spatial distributive character of air pollutants in the urban canopy of Beijing. The gentle double-peak character of the mean diurnal variation of PM2.5 and PM10 was closely related with the evident/similar diurnal variation of turbulent momentum fluxes, sensible heat fluxes, and turbulent kinetic energy at various heights in the urban canopy. Besides, under the condition of calm weather, the concentration of PM2.5 and PM10 declined with height slowly, it was 90% of 8 m concentration at the low layer, a little lesser than 90% at the middle layer, and 80% at the high layer, respectively. Under the condition of weak cold air weather, the concentration remarkably dropped with height, it was 70% of 8 m concentration at the low layer, and 20%―30% at the middle and high layers, especially the concentration of PM2.5 was even lower.  相似文献   

Water soluble components of PM10 Chongqing, China   总被引：1，自引：0，他引：1  

Luo Qingquan  Xian Xuefu  Chen Gangcai  Yang Qinglin 《中国地球化学学报》2005,24(2):155-157

The concentrations of water soluble ions (Na⁺, NH₄ ⁺, K⁺, Mg²⁺, Ca²⁺, NO₃ ^-, Cl^-, and SO ₄ ^2- ) in PM₁₀ samples collected on cellulose filters by a medium-volume cascade impactor were determined, which were obtained from three kinds of areas in Chongqing: industrial area (Jiulongpo district), commercial and residential area (Jiangbei district) and background area (Jinyun Mountain in the Beibei district). The results showed that except for the background site, the annual average values of PM₁₀ are 23% – 61% higher than the national air quality standard (GradeII) (0.1 mg/m³), even that the value of the control site is still 20% higher than American standard (0.05 mg/m³). This implied that serious pollution of fine particles occurred in Chongqing. Nine kinds of soluble ions in water of PM₁₀ were analyzed by ion chromatography (IC) and the annual average concentrations follow the order of [SO ₄ ^2- ] > [NO³ _-] > [Cl^-] > [F^-], and [Ca²⁺] > [NH₄ ⁺] > [K⁺] > [Na⁺] > [Mg²⁺]. Their values were different in these areas: the industrial area > the commercial and living area > the control area. As for NH_{4 +}, K⁺, Ca²⁺, NO₃ ^- and SO ₄ ^2- , their seasonal average concentrations show a similar variation trend: the values in spring and fall were higher than those in summer and winter. The seasonal average concentrations of [Cl^-], [F^-], [Na⁺] and [Mg²⁺] are much lower than those of other ions. However, the concentrations of [Na⁺] changed more greatly in different seasons than those of the other three ions. Correlation coefficients showed that the three areas have been polluted by coal smoke and dust to different extents, while some local resources of pollution should be taken into consideration as well.  相似文献   

兰州市2001年沙尘气溶胶质量浓度的特征分析   总被引：11，自引：14，他引：11  

权建农  奚晓霞  王鑫  李杰  张镭 《中国沙漠》2005,25(1):93-97

 分析了2001年沙尘暴期间兰州与靠近沙尘源区的武威的沙尘浓度和粒径分布特征,并运用对数正态分布规律拟合了沙尘粒径的分布。通过对比武威、皋兰和兰州沙尘暴期间沙尘浓度的变化以及武威与兰州的沙尘粒径分布特征,揭示了河西走廊沙漠对兰州市沙尘暴的影响。  相似文献   

IEC的风机选型参数估算方法在中国的适用性研究     

黄林宏  宋丽莉  李刚  王丙兰  张永山 《气象》2016,42(12):1522-1530

国际电工委员会编制的《风力发电机组设计要求》(IEC 61400-1)推荐了针对风电机组安全等级评估的极端风速和湍流强度特征值估算方法,因其简单便捷,在风电领域被广泛采用。利用全国风能资源专业观测网的193座测风塔观测数据,对IEC推荐的极端风速计算方法与我国规范推荐的基于极值I型概率分布方法进行比较,发现两种方法计算的193座塔70 m高度层50年一遇10 min平均最大风速,仅有7座测风塔较为一致,差异在±1%;IEC推荐方法的计算结果多数偏小,其中偏小10%以上的测风塔有121座,偏小30%以上的有44座测风塔,而偏大10%以上的只有9座测风塔;IEC方法计算的极值风速大幅度偏小的测风塔主要分布在台风影响的东南沿海地区,偏差较小的测风塔主要分布在西北和华北地形平缓区域,但同时偏大10%以上的测风塔也多分布在这一地区。以目前行业领域普遍采用的以15 m·s~(-1)风速的平均湍流强度作为风电机组选型指标,与严格按照规范,以15 m·s~(-1)风速段所有样本湍流强度的90%分位数处的值作为指标进行风电机组等级确定作对比,发现193座塔中有46座塔的选型是不安全的,甚至相差两个等级。  相似文献   

2013年济南市大气能见度与相对湿度和PM10、PM2.5的关系     

吕建华  彭岩波  谢刚 《气象与环境科学》2016,39(4):93-97

对济南市2013年1—12月的能见度、相对湿度、PM10及PM2.5逐时监测数据分析,结果表明：能见度、相对湿度、PM10和PM2.5浓度有明显的月变化和日变化规律。在各项污染物中,能见度与颗粒物的相关性最高,与PM10的相关系数为-0.6718,与PM2.5的相关系数为-0.7422;在气象因子中,与相对湿度的相关性最高,相关系数为-0.6501。不同季节条件下,能见度与PM2.5的相关性明显优于PM10的,冬季能见度与颗粒物的相关性明显优于其他季节的。  相似文献   

上海市PM_(10)浓度四季遥感模型研究          下载免费PDF全文

李薛  龚绍琦  付东洋  张莹  刘大召  丁又专  李懿超  孙庆飞  顾超  许智棋 《大气科学学报》2016,39(1):126-132

通过分析2001—2012年上海市PM_(10)浓度(由API(Air Pollution Index)转化得到)的变化规律,构建了上海市PM_(10)浓度的遥感反演模型。结果表明:1)上海市PM_(10)浓度存在季节性变化,应分别建立遥感反演模型。2)分析MODIS气溶胶光学厚度(Aerosol Optical Depth,AOD)产品与PM_(10)浓度之间的相关性发现,AOD须经过垂直和湿度订正才可与PM_(10)建立较好的关系。3)结合垂直和湿度订正分别建立的上海市PM_(10)浓度春夏秋冬四季的遥感反演模型均通过了拟合度检验,其中春季模型采用指数函数、夏季和秋季模型采用二次多项式函数、冬季采用幂函数、全年采用二次多项式函数,利用此四季模型反演上海市PM_(10)浓度具有较高的可信度。  相似文献   

2007年夏季江淮强降水过程中10~30d低频变化及其与对流层上层波包活动的联系          下载免费PDF全文

陈丹萍  管兆勇  侯俊  奚子惠 《大气科学学报》2016,39(2):177-188

利用NCEP/NCAR再分析和全国740站逐日降水资料,运用一点滞后相关等方法,对2007年夏季江淮流域强降水期间低频振荡的波动活动特征及其与降水低频变化的联系进行了分析。结果表明,在2007年夏季降水中,降水低频分量起着重要作用。降水的低频振荡主周期为10~30d,降水距平时间序列与10~30d低频分量具有较好的对应关系。低频扰动在对流层上层和低层都呈现波列状分布,且在降水活跃位相时,低频环流在高、低层具有斜压结构。在对流层上层,低频扰动有缓慢的东移倾向,相速度为每天2~3个经度。西风带中存在多次移动性波列向下游的传播,且在120°E以西以每天14经度的群速度向下游频散能量,表明10~30d低频波动具有明显的下游发展特征。在强降水开始5d前,低频波动与能量可起源于高纬的乌拉尔山附近,沿着西北-东南向的路径向下游传播。下游发展的低频波动为江淮流域带来了能量,为强降水的发生提供了条件。这些结果加深了人们对低频波动在江淮流域强降水过程中所起作用的认识,可为寻找江淮流域强降水过程预报线索提供科学依据。  相似文献   

Satellite-measured atmospheric aerosol content in Korea: anthropogenic signals from decadal records     

Sunyurp Park 《地理信息系统科学与遥感》2016,53(5):634-650

Spatiotemporal characteristics and anthropogenic signals of aerosol optical thickness (AOT) distributions over Korea are investigated in this study using AOT time-series data from the Moderate Resolution Imaging Spectroradiometer (MODIS). AOT observations, a quantitative measure of the atmospheric quality, had significant geographical variations during the study period (2000–2010). Comparing metro cities or counties with similar populations, western regions showed higher AOT values than eastern regions. Particular matter with a diameter < 10 µm (PM₁₀), including aeolian dust or yellow dust, is the primary component of atmospheric aerosols, and their transport into the region has shown a strong seasonal pattern with its peak from March to April and lows from July to September. These seasonal dust patterns, however, did not correspond well to temporal AOT records, which typically reached the maximum level in June nationwide. Rather, widespread regional fire events and humidity showed significant correlations with AOT time-series. This correlation rapidly increased as the range of fire occurrence was extended to the west as far as 115°E. The relative humidity also had a significant correlation with AOT during the month of June. In addition to urban emission of anthropogenic aerosols, regional biomass burning and secondary growth of hygroscopic aerosols are considered important contributors to the degradation of the atmospheric environment during the non-Asian Dust season over the Korean Peninsula.  相似文献   

北京西北城区一次重污染过程中PM₁₀的氧化损伤能力研究     

席春秀  邵龙义  吴凡  常玲利  李杰 《岩石矿物学杂志》2018,37(3):492-496

为评估大气重污染期间北京市可吸入颗粒物(PM_(10))的毒性,采集2016年3月份一次大气重污染过程中北京市大气PM_(10)样品,应用质粒DNA损伤评价法来研究其氧化损伤能力。结果表明,雾霾期间PM_(10)对DNA的损伤率高于雾霾逐渐消退时期,远高于雾霾前期清洁天,颗粒物对DNA损伤率随剂量的增加而增加。雾霾前后PM_(10)水溶样品的平均TD_(20)值表现为雾霾前清洁天(788.01μg/mL)雾霾消退后期(470.40μg/mL)雾霾期间(55.78μg/mL),说明氧化能力雾霾期间雾霾消退后期雾霾前清洁天。另外通过雾霾前后数据对比得到,暴露毒性指数TI大小顺序为雾霾期间(13 245.06)雾霾消退后期(1 658.87)雾霾前清洁天(254.08),说明雾霾期间PM_(10)对人体危害更大。  相似文献   

菲律宾迪纳加特岛30^#矿权区红土型镍矿床地质特征及成矿作用探讨          下载免费PDF全文

江胜国  王志刚  曹健 《地质找矿论丛》2018,33(2):299-305

30~#矿权区位于菲律宾迪纳加特岛北部,区内发育有红土型镍矿床。本次勘查圈定4处矿(化)体,其中以Ⅰ、Ⅱ、Ⅲ矿(化)体的矿化范围较大,厚度变化系数为45%~50%(相对稳定),经济价值较高。红土型镍矿体平面上呈地毯状展布于地表,厚度受地形控制,富镍矿体分布于矿权区东部的5、6、11、12小区;剖面上从地表向深部矿体为铁质红土层、松散红土层及高岭土化蛇纹石化橄榄岩层。30~#矿权区红土镍矿矿床的形成经历了从普通矿到富矿两个阶段,红土镍矿石属于酸性矿石。  相似文献