降水量变化对大气污染物浓度影响分析

系统分析了2001～2010年南通市城区中大气自动监测站和降水监测点位数据,得出:10年间逐年降水量与二氧化硫年均浓度呈现高度线性负相关,其它时空降水量与大气污染物浓度分布中呈现非线性显著性负相关。降水量大污染物浓度就小,反之就大。2006～2010年5年平均降水量1083.49mm,比2001～2005年5年平均降水量多出244.97mm,大气污染指标5年平均浓度下降幅度为:可吸入颗粒物0.013mg/m3、二氧化硫0.009mg/m3、二氧化氮无变化。10年的平均季度降水量夏季最大为467.97mm,对应的夏季大气污染物最小均值为:可吸入颗粒物0.073mg/m3、二氧化硫0.026mg/m3;10年平均季度降水量冬季最小为137.84mm,对应的冬季大气污染物季最大均值为:可吸入颗粒物为0.104mg/m3、二氧化硫0.034mg/m3和二氧化氮0.036mg/m3。     

典型室内公共场所中CO_2的污染特征分析

选取典型的室内公共场所,按照室内空气检测标准进行布点采样,检测这些场所的C02浓度及采样时的温度、湿度及空气流速结果发现,商场内C02浓度基本都在标准限值内,超市内C02浓度超标严重,且C02分布与超市内采样层区之间无明显的相关性。其它类型场所C02分布各有差异,但浓度值基本在标准限度值上下浮动统计结果:公共场所内影响C02浓度的主要原因是空气流速与人群密度的大小空气流速越快,C02浓度越低;人群密度越大,C02浓度越高此外,根据,James L Repace理论进行分析发现,各类公共场所空气交换状况均较差,存在威胁人们健康的风险。     

LPG充装站紧急切断阀失效模式分析

紧急切断阀作为LPG充装站的重要安全附件之一,当遇到突发情况时,可远程控制紧急切断阀迅速关闭,避免事故的进一步蔓延。若LPG充装站紧急切断阀安装位置不合理,或缺乏定期检验检查与维护保养,均可能导致紧急切断失效。通过对LPG充装站紧急切断阀的工作原理及安装位置,常见失效模式分析及预防,定期检验检查及维护保养注意事项进行详细研究,为LPG充装站对紧急切断阀进行年度检查及维护保养和相关检验单位进行定期检验提供参考。     

潮汐流动平均离散的分析与计算

利用二维潮汐流动纵向流速任意分布下离散系数的计算公式,对几种典型的流速分布建立了潮平均离散系数D_us与分时段按恒定流处理所得的潮平均离散系数D_s之间的关系。通过水槽试验对计算结果进行了定性验证。把这种方法应用于珠江,根据实测的流速分布资料,由恒定流的剪切离散结果获得了广州河段潮平均的离散系数。     

北京地区大气细菌粒子浓度及其分布

用ANDERSEN生物粒子采样器在北京西单和怀柔观测了大气细菌粒子浓度及浓度分布。结果表明,大气细菌粒子年平均浓度,西单为3103个/m3,怀柔为623个/m3。不同粒度的大气细菌粒子浓度在一天内西单有7:OO、19:00二个高峰时和13:00、夜间1:00二个低谷时;而怀柔有19:00~22:00一个高峰时和13:00一个低谷时。大气细菌粒子的浓度分布是从1~6级逐级减小。小于8.2μm的可吸入细菌粒子:西单为82.4%,怀柔为64.0%。      

Concentrations of carbon monoxide and methane at two heights above a grass field and their deposition onto the field

To investigate whether wind is a significant driving force in the diffusion of CO and CH₄ from the atmosphere into soil, we measured the concentrations of these two gases at two heights above a temperate grass field in Japan and estimated their deposition velocities using micrometeorological techniques. The concentrations were inversely correlated with wind speed, indicating that the local concentrations were influenced by ground sources. The CO and CH₄ concentrations at 0.33 m were usually lower than those at 1.3 m. Although nocturnal data are suspected to be non-stationary, by selecting several periods when the changes of the concentrations were small but larger than analytical precision, we obtained a CO velocity of 2.9 and 3.9×10⁻² cms⁻¹, agreeing with a CO deposition velocity, 3.4×10⁻² cms⁻¹, obtained by applying a method using CO₂ as a tracer. The CH₄ influx obtained by the method using CO₂ as a tracer was 13 ngm⁻² s⁻¹. The ranges of the CO deposition velocity and CH₄ influx were similar to those obtained in previous studies in grassfields and in a nearby arable field using a closed-chamber technique. This shows that light winds do not greatly accelerate CO and CH₄ uptake by soil.     

家庭室内空气中细菌浓度分布之分析

对家庭室内空气的细菌浓度,在不同时间段的分布进行了研究分析。采用平皿沉降法,测得结果：清晨７：００为强污染时,晚１９：００为弱污染时。并对居室清扫方式提出建议,以促进生存空间的环境质量的改善。     

Heavy metal concentrations in water and sediments in Tasik Chini, a freshwater lake, Malaysia

The purpose of this paper are to determine the concentration of heavy metals namely cadmium (Cd), copper (Cu) and lead (Pb) in water and sediment; and to investigate the effect of sediment pH and sediment organic matter on concentration of cadmium, copper and lead in sediment at oxidation fraction. For this purpose the concentration of heavy metals were measured in water and sediments at 15 sites from Tasik Chini, Peninsular Malaysia. The sequential extraction procedure used in this study was based on defined fractions: exchangeable, acid reduction, oxidation, and residual. The concentration of heavy metals in residual fraction was higher than the other fractions. Among the non-residual fractions, the concentration of heavy metals in organic matter fraction was much higher than other fractions collected from all sampling sites. The pH of the sediment in all sites was acidic. The mean pH ranges from 4.8 to 5.5 with the higher value observed at site 15. Results of organic matter analysis showed that the percentage of organic matter present in sediment samples varies throughout the lake and all sites of sediments were relatively rich in organic matter ranging from 13.0% to 34.2%. The highest mean percentage of organic matter was measured at sampling site 15, with value of 31.78%.     

毒性废水稀释中强度改变与浓度改变的跟随性研究

适用于已知毒物和毒性应用剂量测定的经典技术方法,以样品稀释过程中毒性强度改变与浓度改变的等比率跟随性为基础。废水中的毒性物质常以未知和混合为特征,高毒性的样品现状浓度距离方法预试验中最小全致死浓度较远,以已知毒物重铬酸钾毒性为对照,形成5种毒物高层级等强度毒性,通过这些高毒性废水同步等比率稀释后毒性改变的同步性测定试验,证明毒性废水稀释中强度改变与浓度改变的跟随状态具有不确定性。     

Probability law of concentration in plumes dispersing in an urban area

The relationships between various normalized higher-order concentration moments in plumes dispersing in a built-up (urban) environment have been investigated using a large concentration data set obtained in a boundary-layer water channel. This data set consists of measurements of plume dispersion in a number of idealized obstacle arrays (e.g., cubical and non-cubical obstacles in aligned and staggered arrangements with uniform, random and alternating heights). A remarkably robust feature of all the concentration data was the observed collapse of the third- and fourth-order normalized concentration moments on the second-order normalized concentration moment. The data are shown to collapse to a series of universal curves (independent of the geometry of the obstacle array) and these curves were found to be identical to those observed previously for open-terrain plumes. The results imply that the probability law of concentration in a plume dispersing in either a built-up environment or open terrain has a universal form that can be specified by at most two independent parameters. The universal functions representing the relationships between the normalized concentration moments were found to be well modeled (approximated) using a two-parameter clipped-gamma probability law for the concentration. Finally, the clipped-gamma distribution was found to be in very good conformance with the measured probability distribution of concentration for plumes dispersing in a built-up environment.