吐鲁番空气中总悬浮颗粒物和可吸入颗粒物的相关性

于2009年对吐鲁番市大气中总悬浮颗粒物(TSP)、可吸入颗粒物(PM10)监测结果进行了统计分析并讨论。     

2008年奥运前后北京城、郊PM2.5及其水溶性离子变化特征

2008年6月至9月,在北京城区清华大学和郊区密云水库开展大气颗粒物观测,采集了PM2.5样品共180个,并获得了PM2.5及12种水溶性离子的质量浓度.观测期间城区和郊区PM2.5浓度接近,分别为68.9 μg·m-3和52.9μg·m-3;二次无机离子SO42-、NO3-和NH4+是PM2.5中含量最高的水溶性离子...     

城市道路二次扬尘中PM_(10)浓度量化模型实验研究

机动车行驶条件、路况与道路二次扬尘中PM10浓度有密切的关系。通过对它们设计正交试验和多元回归统计分析,得到PM10浓度计量模型:ρ=0.0314W0.8248v0.537q0.7021M0.357,该方程具有99%的置信度,且拟合的较好。经回归系数显著性检验,自变量对因变量的影响均极为显著,其显著性大小依次为:道路路面粉尘负荷、机动车车型、车速和车流量。最后采用实测值与模型计算值间的均方差对模型进行验证,结果表明该模型具有较高的可信度。     

广州市PM_2.5和PM_1.0质量浓度变化特征

文章报道了2005年干季和2006年湿季广州市大气细粒子PM2.5和PM1.0质量浓度的实时监测情况。监测结果表明:干季监测点PM2.5日均质量浓度在11.8～164.0μg/m3之间,总平均值为81.7μg/m3;湿季日均质量浓度在19.9～121.2μg/m3之间,总平均值为57.7μg/m3。干季PM1.0日均质量浓度变化范围为14.9～129.1μg/m3,总平均值为59.4μg/m3;湿季日均质量浓度在11.9～86.7μg/m3之间,总平均值为52.9μg/m3。对比发现,PM1.0总平均质量浓度在干、湿季相差很小,且与湿季PM2.5总平均质量浓度也相差不大,显示PM1.0具有相对固定成因来源且基本不受季节变化影响,而且湿季PM2.5的组成主要由PM1.0大气细粒子构成。干季PM2.5和PM1.0质量浓度日变化特征呈明显夜间高、白天低的特点,质量浓度的最大值都出现在晚上21:00左右;湿季由于雨水频繁,没有明显的日变化特征。气象分析表明,干季大气细粒子质量浓度主要受冷空气影响,而湿季主要受降雨影响。     

Mutagenic properties of PM2.5 air pollution in the Padana Plain (Italy) before and in the course of XX Winter Olympic Games of "Torino 2006"

PM2.5 is one of the most important aspects of environmental health. This air pollutant is breathable and it is implicated in several chronic adverse health effects such as the decrease of respiratory functionality and cancer. Several in vitro bioassays are able to predict the mutagenic/carcinogenic activity of the environmental pollutants and mixtures of them. In this study PM2.5 air pollution was daily monitored in three cities located in the Northern part of Italy and the mutagenic properties of the PM2.5 organic extracts were also assessed. Samplings lasted 14 months and cover the period of the Winter Olympic Games of "Torino 2006". In this work, the levels of PM2.5, its mutagenic properties (detected with Salmonella typhimurium assay), the role of the Olympic Games as environmental factor and some meteorological data are discussed. The mean concentration of PM2.5 measured in Torino was 45.4 (+/-30.6) microg/m(3), in Pavia 37.6 (+/-25.6) microg/m(3), in Verona 43.1 (+/-28.5) microg/m(3). Findings of the monthly pool bioassay were in Torino 107 (+/-104) net revertans/m(3), in Pavia 108 (+/-89) net revertans/m(3), in Verona 128 (+/-109) net revertans/m(3). The Olympic Games period data show that PM2.5 pollution and its load of mutagenic potential are different and partially independent phenomena. The Olympic Games had not a great impact on the PM2.5 pollution. The exclusive PM2.5 gravimetric analysis shows a potential human risk if compared with the latest international guide values but it does not describe exhaustively the human health risk associated to the presence of this particular air pollutant. Moreover, the chemical and biological activity qualification of the PM organic extracts as a whole, can instead improve the knowledge.     

北京奥运时段河北香河大气污染观测研究

为监测评估周边地区大气污染对北京的可能影响,2008年6～9月北京奥运时段,在北京东南方向河北香河开展了大气污染物SO2、NOx、O3、PM2.5和PM10的连续在线观测,结合地面气象资料和HYSPLIT轨迹模式探讨了污染物的来源与传输过程.结果表明,香河地区大气污染较为严重,上述污染物观测期间日均最高值(日均值±标准差)分别达到84.4(13.4±15.2)、43.3(15.9±9.1)、230(82±38)、184(76±42)和248(113±52)μg.m-3,特别在奥运会开幕前后的7月20日～8月12日之间出现了2次持续污染过程,导致O3和PM10分别超过国家二级标准46 h(超标率9%)和11 d(46%),PM2.5则超过美国EPA标准18 d(75%).奥运时段8～9月的大气污染物日均值较6～7月日均值有明显降低:SO2从27.7μg.m-3下降到5.8μg.m-3;NOx从18.6μg.m-3下降到13.2μg.m-3;O3从96μg.m-3下降到80μg.m-3;PM2.5从90μg.m-3下降到60μg.m-3;PM10从127μg.m-3下降到106μg.m-3.NOx、PM2.5和PM10统计(月为单位)日变化为双峰型,峰值分别出现在07:00和20:00左右;臭氧呈单峰型,峰值出现在14:00～16:00之间.香河地区大气污染受局地排放和外源输送共同影响,持续的偏南气流易造成污染物积累,而偏北气流有利于污染物扩散,降水可明显清除大气中的污染物质.通过计算7月20日～8月12日香河和北京奥运村PM2.5小时平均浓度之间的超前相关系数,发现香河超前北京6～10 h时相关性较大(0.57r0.65,p=0.01),最大相关系数出现在超前8 h,表明上述时间段内香河实时观测数据对北京大气PM2.5污染超标事件可能具有预警作用.     

燃煤电厂超细粉尘的危害及控制

燃煤电厂超细颗粒物通常富集各种重金属元素,PAHs（多环芳烃类）,PCDD/Fs（二恶英类）等有机污染物,这些多为致癌物质和基因毒性诱变物质,危害极大。吸附有重金属的PM2.5对NOX和SO2起催化作用,加剧了大气酸雨和光化学烟雾的形成,是诱发臭氧层破坏的重要因素。国外近年来在这方面作了大量的观测和研究工作。对燃煤电厂超细粉尘的危害及控制进行了研究。     

北京市大气PM_(10)和PM_(2.5)中有机物的时空变化

2005年四季在北京市不同功能区9个采样点采集大气PM10和PM2.5样品,并对其中有机物污染水平、分布特征及不同功能区PM10和PM2.5中有机物的相关性进行了探讨.结果表明,市区PM10和PM2.5中有机物年均值分别为41.39 μg/m3和34.84 μg/m3,是对照区十三陵的1.44倍和1.26倍;冬季有机物污染最严重,分别为春季的1.15、 1.82倍,秋季的2.06、 2.26倍,夏季的4.53、 6.26倍.不同季节PM2.5与PM10中EOM的比值超过0.60, 并呈现一定季节差异.各功能区有机污染表现出工业区(商业区)＞居民区(交通区、对照区)的变化趋势,且不同功能区PM2.5中EOM对PM10中EOM的影响程度各异.有机组分的年均值有非烃＞沥青质＞芳烃＞饱和烃的变化规律,而污染源的季节性排放是造成有机物组分季节变化的主要原因.     

贡嘎山大气气溶胶中水溶性无机离子的观测与分析研究

2005年12月～2006年11月在贡嘎山东坡海拔1 640　m处,利用大流量滤膜采样器对大气中的气溶胶粒子进行了分级采样,并用离子色谱(IC)分析了气溶胶中水溶性无机成分的含量.结果表明,PM_2.5和PM₁₀中总水溶性无机离子年平均浓度分别为6.46和8.86 μg/m³,其中主要的3种离子SO^2-₄、NO^-₃和NH⁺₄,占PM_2.5和PM₁₀中总水溶性无机离子浓度的82%和85%.Na⁺、 NH⁺₄、 K⁺、Cl^-和SO^2-₄主要分布在细粒子中,NO^-₃、Mg²⁺和Ca²⁺在粗细粒子中各占一半.雨季Na⁺与Cl^-相关性明显增强,PM_2.5和PM₁₀中Na⁺与Cl^-的相关系数R²分别为0.87和0.84. PM₁₀中SO^2-₄与NH⁺₄的量浓度比值接近1∶2,表明SO^2-₄与NH⁺₄主要以(NH₄)₂SO₄形式存在.     

Distributions and sources of n-alkanes in PM2:5 at urban, industrial and coastal sites in Tianjin, China

Aliphatic hydrocarbons (n-alkanes) associated with fine particulate matter were determined in the ambient air of urban, industrial and coastal areas in Tianjin, China, where intensive coal burning for industrial and domestic purpose takes place. n-Alkane homologues from C12 to C35 were quantifiable in all samples with C20–C31 being the most abundant species. Average concentrations of the total n-alkanes were 148.7, 250.1 and 842.0 ng/m3 in July, April and January, respectively. Seasonal variations were mainly attributed to ambient temperature changes and coal combustion for residential heating. Among the three studied areas, the highest levels of n-alkanes were observed in the industrial complex in winter and spring, but in summer the coastal alkane concentration moved up to the highest. A mono-modal distribution for n-alkanes was observed in spring and summer with odd carbon number predominance and a maximum centered at C27–C31, suggesting the release of plant wax into the atmosphere. The bimodal distribution with maxima at C22 and C26 observed in winter indicated a substantial influence of fossil fuel sources. All the CPIs (CPI1, CPI2, CPI3) values, varying between 0.64 and 1.97, indicated the influence of anthropogenic emissions on fine organic aerosols. The estimated contributions of plant wax to total n-alkanes were on average of 12.9%, 19.1% and 26.1% for winter, spring and summer, respectively.