Polycyclic aromatic hydrocarbon in rain and street runoff in Amman, Jordan

Concentrations of polycyclic aromatic hydrocarbons(PAHs) were determined in the rain and street runoff samples from two sites in the vicinity of Amman City during the pluvial period 1999--2000. The results showed that elevated levels of PAHs were detected in the city center(site 1 ) than the residential area( site 2) and that the levels were higher in street runoff than rain samples of the same sites. The highest concentration of PAHs in both street runoff and rain samples were observed in the first rainy month( November 1999) which indicated a wash out effect of PAHs originating from vehicular emission accumulated during the long dry summer season before sampling. Within the investigated cold winter seasons, fluctuations in PAHs concentration were observed. The variation was attributed to the fossil combustion for heating purposes and to intervals between rainfalls: as the longer the intervals between rains were, the higher the PAH concentration were. Removal of PAHs from the atmosphere through precipitation over the investigated period varied with time and places depending on the amount of rainfall where higher rainfall removed higher amount of PAHs from the almosphere. The amount of PAHs washed out through precipitation was estimated to be around 14.8 mg/m^2 and 21.1 mg/m^2 for sites 1 and 2 respectively.     

Geochemical Distribution and Bioavailability of Heavy Metals and Oxalate in Street Sediments from Rio de Janeiro, Brazil: A Preliminary Investigation

As urbanisation accelerates within less-economically developed countries, populations in cities such as Rio de Janeiro are subject to numerous health risks relating to “heavy metal”, sewage and vehicle pollution. These risks apply especially to children, through inhalation and dermal contact with pollutant-rich street sediments that reflect contamination from atmospheric deposition and act as effective sinks for heavy metals and oxalates. To assess the nature and extent of these risks street sediments were collected from industrial, commercial, residential and recreational areas with varying traffic densities within Rio de Janeiro. A modified selective extraction procedure was used to study the geochemical partitioning and bioavailability of Fe, Mn, Zn, Cu, Cr, Ni, Pb and C₂O ₄ ⁻ . Oxalate partitioning has not been studied by traditional sequential methods and results from this procedure highlight the potential bioavailability of both oxalates and “heavy metals”, especially Pb and C₂O ₄ ⁻ in industrial and recreational areas.     

建立长江三峡库区船舶污染应急反应体系的意义和设想

三峡库区环境保护工作为世人所瞩目，库区船舶防污工作是整个库区环保工作的重要组成部分。文中论述了在库区建立完善的船舶污染应急体系的必要性，并就如何建立船舶污染应急体系提出了设想。     

城市低矮街道峡谷汽车排放NOx扩散模式的初探

通过对武汉市珞狮路路段的车流量、NOx 浓度和气象要素的调查与监测 ,分析了珞狮路交通流量的特征 ,给出了源强的计算公式 ,并重点讨论了街道两侧环境中 NOx 浓度与各种影响因素之间的关系 ,发现城市低矮峡谷中 NOx 扩散不同于以往的研究结果 ,有其自己的特殊性。最后提出了扩散模式参数的处理方法 ,为建立城市低矮街道峡谷排放 NOx 扩散模式提供了基础     

汞蒸气在参差建筑街区中沉积过程模拟

利用计算流体动力学方法,分别选用参差比为0.0, 0.2, 0.4, 0.6和0.8等5种建筑模型,探讨了在水平自然风条件下重密度污染源(汞)在不同参差比建筑物间的沉积过程,以及街区内行人层汞浓度与建筑参差比之间的关系.模拟结果发现,城市街区建筑物高低错落分布的布局会促进高空汞污染源在行人层的聚集,使得街区行人层汞浓度明显增大;并且随着街区建筑物参差比的增大,最高汞浓度值所在的街道有序地靠近来流上游,而较高建筑物背风面街道行人层汞质量流量明显高于较矮建筑物背风面街道行人层汞质量流量.     

街道峡谷内不同车道污染物扩散的数值模拟

为掌握不同位置车道污染物的扩散规律,提出降低街道峡谷内居民与行人交通源暴露水平的可能途径,采用二维k-ε两方程模型和组分输运方程对典型结构双车道街谷内的流场与不同车道污染物的扩散进行模拟,模拟结果与风洞试验结果相符合. 研究发现:迎风车道的污染物更易于向街道峡谷外部扩散;不同位置车道的污染物均在背风侧堆积,可使两侧人行道暴露水平相差5倍. 街道峡谷底部污染物分布对车道位置较敏感,车道位置向街道峡谷中部靠拢,将使得背风建筑物底部及人行道的污染物浓度明显降低;迎风侧污染物浓度对车道位置不敏感,但当车道位置处于迎风侧次级旋涡内时,将导致迎风建筑物底部及人行道的污染物浓度近乎成倍增长. 将车道位于街道峡谷中部,优先采用道路两侧绿化,是增加行人舒适度和减少行人交通源暴露水平,并改善大楼低层住宅及底部出入口、临街商铺等人群活动区空气质量的可行途径之一.      

长江三峡库区猕猴桃资源特点及其发展策略

猕猴桃是我国特有的珍贵果树资源，长江三峡库区是猕猴桃的原产中心地带，物种资源丰富，生态条件优越，发展潜力较大。本文分析了三峡库区猕猴桃的资源特点，阐述了开发利用猴桃桃资源的必要性和优越性，以及有利条件，提出了发展猕猴桃生产的若干策略。     

Estimation of PM_(10) in the trafc-related atmosphere for three road types in Beijing and Guangzhou,China

The levels of roadside PM10in Beijing, China, were investigated in 2011 and 2012 on a seasonal basis to estimate the population exposure to particulates for three road types. The measurements of PM10 were also conducted in the southern Chinese megacity of Guangzhou for comparison purposes. The results showed that roadside PM10in Beijing correlated strongly with the PM10background in the urban atmosphere. The levels of PM10in street canyons were markedly higher than those along the open roads and in crossroad areas because of limited ventilation. An elevation of PM10was observed in April, which was possibly due to the sand storms that frequently occur in the spring. Based on these observations, roadside PM10in Beijing could have multiple origins and was to some extent dispersiongoverned. In Guangzhou, the roadside PM10did not closely relate to the background values. The PM10 pollution was greatly afected by local trafc conditions. The simulation of PM10 for diferent road types was completed during the study period using the Motor Vehicle Emissions Factor Model(MOBILE6.2) as an emission model and the California Line Source Dispersion Model(CALINE4) and Operational Street Pollution Model(OSPM) as dispersion models. The MOBILE6.2/CALINE4 software package was demonstrated to be sufcient for the simulation of PM10in the open roads and crossroad areas in both Beijing and Guangzhou, and the simulation results of roadside PM10 in the street canyons by the MOBILE6.2/OSPM package were in close agreement with those of the measurements.     

Total pollution effects of urban surface runoff

e values of MFFn (mass first flush ratio) and FF30 (first 30% of runoff volume) can be considered as split-flow control criteria to enable more effective and economical design of structural BMPs (best management practices) facilities.     

沈阳市不同粒径区间街道灰尘中Pb的空间分布特征研究

研究了沈阳市一环及其内主要街道在不同粒径区间灰尘中Pb的空间分布特征,共采集61个样品。分别测定了灰尘在100～125,63～100和小于63μm这3个粒径区间中Pb的含量。结果表明：此3个粒径区间中Pb含量相近,63—100μm粒径中Pb含量稍高;铁西区污染程度处于市内5区之首。