Quantifying air pollution attenuation within urban parks: an experimental approach in Shanghai, China

Parks with various types of vegetations played an important role in ameliorating air quality in urban areas. However, the attenuation effect of urban vegetation on levels of air pollution was rarely been experimentally estimated. This study, using seasonal monitoring data of total suspended particles (TSP), sulfur dioxide (SO(2)) and nitrogen dioxide (NO(2)) from six parks in Pudong District, Shanghai, China, demonstrated vegetations in parks can remove large amount of airborne pollutants. In addition, crown volume coverage (CVC) was introduced to characterize vegetation conditions in parks and a mixed-effects model indicated that CVC and the pollution diffusion distance were key predictors influencing pollutants removal rate. Therefore, it could be estimated by regression analysis that in summer, urban vegetations in Pudong District could contribute to 9.1% of TSP removal, 5.3% of SO(2) and 2.6% of NO(2). The results could be considered for a better park planning and improving air quality.     

Spatio-temporal variations of nitrogen in an agricultural watershed in eastern China: catchment export, stream attenuation and discharge

Using the monthly hydrogeochemical data of ChangLe River system from 2004 to 2008, total nitrogen (TN) export load (S(n)) from nonpoint sources (NPS) to stream and in-stream attenuation load (A(L)) was estimated by the inverse and forward format of an existing in-stream nutrient transport equation, respectively. Estimated S(n) contributed 96 ± 2% of TN entering the river system, while A(L) reduced the input TN by 23 ± 14% in average. In-stream TN attenuation efficiency in high flow periods (10 ± 5% in average for the entire river system) was much lower than that in low flow periods (39 ± 17%). TN attenuation efficiency in tributaries (28 ± 16% in average) was much higher than that in mainstream (11 ± 8%). Hydrological conditions are important in determining the spatio-temporal distributions of NPS TN export, stream attenuation and discharge. Increasing the water residence time might be a practical method for mitigating stream TN.     

香溪河流域土地利用格局演变对非点源污染的影响研究

以分布式模型SWAT为研究工具,在气候、土壤等因素不变的情况下,模拟了三峡库区香溪河流域土地利用格局演变对于非点源污染的影响.研究结果表明,自20世纪80年代至2007年,研究区由土地利用所造成的非点源污染TN总体呈减少趋势,4种土地利用情景下模拟得到的年均非点源污染TN分别为1 841.60、824.86、1 790...     

液化石油气轿车实际道路污染物排放特征

利用PEMS对国2技术LPG出租轿车和汽油轿车的实际道路排放进行测试,基于测试数据对LPG轿车排放特征进行解析,并与汽油轿车的排放因子进行对比分析.结果显示:速度和行驶模式对LPG轿车污染物排放影响明显;LPG轿车CO 2、CO、HC和NOx污染物的实测排放因子分别为(169.5±22.2)、(2.18±2.38)、(...     

基于活性污泥的厨余垃圾厌氧发酵产酸研究

以厨余垃圾和活性污泥为原料,考察了不同接种比例对厌氧发酵产物的挥发性脂肪酸产量、pH值和COD去除率的影响.结果表明,当厨余垃圾和活性污泥接种比例为4∶1时,挥发性脂肪酸产量在第3天达到最大值为42.7 g/L,产率提高了40%,COD去除率达到了35.6%,pH值没有发生较大的差异,其变化幅度在4～6之间.     

淀粉-g-丙烯酸/凹凸棒土复合物制备及其吸附废水中NH_4~＋-N性能

采用反相乳液聚合法以凹凸棒土为原料,合成了新型NH4＋-N吸附剂淀粉-g-丙烯酸/凹凸棒土,并进行了氨氮吸附对比实验。结果表明：凹凸棒土氨氮单位吸附量为4.243 mg/g;淀粉-g-丙烯酸/凹凸棒土氨氮单位吸附量为5.301 mg/g,吸附能力比未改性的凹凸棒土提高了25%。淀粉-g-丙烯酸/凹凸棒土的氨氮吸附过程比凹凸棒土更符合Freundlich等温吸附模型。随着pH、温度的升高,凹凸棒土和淀粉-g-丙烯酸/凹凸棒土对NH4＋-N吸附量逐渐增大。     

用熟化法从硫铁矿烧渣中提取铁

用熟化法提取硫铁矿烧渣中的铁 ,熟化温度与硫酸浓度对铁的提取率有显著影响 ,过高的酸浓度不利于铁的提取。为了提高铁的提取率 ,应选择适宜的硫酸浓度和熟化温度。     

上海环保"三年行动计划"的编制与实施分析

环境保护“三年行动计划”的编制,是我国和上海环保计划工作的一项创新性举措。政府以计划实施为抓手,丰富了环境管理方法。文章较详细地介绍了上海环境保护“三年行动计划”编制的指导思想、程序、重要内容,并对实施情况进行了分析。最后还较原则地提出了若干建议。     

KTV、慢摇吧等娱乐场所噪声治理方法研究

近年来,随着KTV,慢摇吧等娱乐场所的增加,娱乐场所带来的噪声扰民问题也日益突出。由于业主、施工单位等缺乏隔声降噪的专业知识,使得这一问题没有很好解决。本文通过对这类噪声的特性分析,根据其具有低频为主、穿透力强、不易衰减等特点,结合工程实例,从提高顶棚、侧墙的隔声量,结构上多采用弹性连接及增加阻尼等角度提出几点治理方法。以隔声、隔振为主,控制这类噪声通过空气传声与固体传声等途径向周围居民区传播。     

Inhibitory effect of nitrobenzene on oxygen demand in lake sediments

Nitrobenzene is an important raw material and product,which presents a heavy threat to the ecosystem.The potential impacts of nitrobenzene on sediment oxygen demand (SOD) were studied in lake sediment ...