泉州市规划区大气污染物总量分配可行性分析

合理的污染物排放总量分配是保证城市发展和环境保护的相协调的重要条件，以可预测实现的环境质量目标；符合可持续发展战略，在保护环境的前提下又可为经济，社会发展提供必要的空间；符合区域目标总量控制为３个基本要求，论证城市功能区划、产业结构特征，污染源特点的泉州规划区大污染总量分配方案的合理性和可行性。     

日光照射对街道峡谷污染物扩散影响的研究

为了分析日光照射对城市街道峡谷机动车污染物扩散的影响．对街道峡谷日光照射的物理模型进行了简化．采用数值模拟技术对日光照射下的城市街道峡谷内气体流动和机动车污染物扩散规律进行了研究。结果表明．在一定条件下。日光照射是研究城市街道峡谷内污染物扩散必须考虑的因素。在污染物扩散受日光照射影响较大的街道峡谷内部．当街道地面或迎风面受日光照射时．街道峡谷内部将出现2个方向相反的漩涡，并导致迎风面建筑物一侧的污染物浓度升高．这与不计日光照射的特征有显著的不同。     

Indoor pollutant mixing time in an isothermal closed room: an investigation using CFD

We report on computational fluid dynamics (CFD) predictions of mixing time of a pollutant in an unventilated, mechanically mixed, isothermal room. The study aims to determine: (1) the adequacy of the standard Reynolds Averaged Navier Stokes two-equation (k−) turbulence model for predicting the mixing time under these conditions and (2) the extent to which the mixing time depends on the room airflow, rather than the source location within the room. The CFD simulations modeled the 12 mixing time experiments performed by Drescher et al. (Indoor Air 5 (1995) 204) using a point pulse release in an isothermal, sealed room mechanically mixed with variable power blowers. Predictions of mixing time were found in good agreement with experimental measurements, over an order of magnitude variation in blower power. Additional CFD simulations were performed to investigate the relation between pollutant mixing time and source location. Seventeen source locations and five blower configurations were investigated. Results clearly show large dependence of the mixing time on the room airflow, with some dependence on source location. We further explore dependence of mixing time on the velocity and turbulence intensity at the source location. Implications for positioning air-toxic sensors in rooms are briefly discussed.     

生物质能利用技术控制污染物排放的作用

化石燃料燃烧利用过程中排放的大量毒害气体和CO2对生态环境造成重大危害,由此产生的环境问题越来越引起世界各国的关注,相应的控制排放技术不断发展,其中生物质能利用由于其CO2零排放成为最有发展潜力的技术之一.采用LCA方法,选择生物质气化联合循环发电、生物质热裂解发电、生物质与煤混烧发电3种方案与燃煤发电进行了对比,分析生物质利用过程减排温室气体CO2、毒性气体(SOX、NOX)的作用.结果表明,在生产1 kW*h电能的生命周期中,3种生物质发电方案的CO2排放量远远小于燃煤发电,特别是生物质气化联合循环发电和生物质热裂解发电两种方案减排CO2达到了87%～94%.由于生物质低硫和低氮特性,该两种方案中NOX和SOX的减排量也非常显著,即使是生物质与煤按1∶9(质量比)混燃都可以达到25.2%和8.9%的减排效果.综合而言,生物质能的利用,不论是气化、热解或者共燃都是减排CO2、NOX和SOX有效措施.     

Integration of Flow and Chemical Sensing for Guidance of Autonomous Marine Robots in Turbulent Flows

We explored the utility of odor-gated rheotaxis (OGR) with a biomimetic robot. OGR is a widely accepted biological plume-tracing strategy that uses mean flow and chemical detection for guidance. In experiments which contrasted the `classic' single-sensor formulation of the strategy against one which used two sensors and against another which combined the use of two sensors and memory of past stimulation patterns we quantified the relative advantages of each. The use of two, spatially separated, chemical sensors confers a significant advantage and still greater performance is obtained with rudimentary memory. The performance of the American lobster under the same turbulent dispersal regime leads us to conclude that significantly more effective plume tracing strategies remain to be discovered.     

Filament-Based Atmospheric Dispersion Model to Achieve Short Time-Scale Structure of Odor Plumes

This article presents the theoretical motivation, implementation approach, and example validation results for a computationally efficient plume simulation model, designed to replicate both the short-term time signature and long-term exposure statistics of a chemical plume evolving in a turbulent flow. Within the resulting plume, the odor concentration is intermittent with rapidly changing spatial gradient. The model includes a wind field defined over the region of interest that is continuous, but which varies with location and time in both magnitude and direction. The plume shape takes a time varying sinuous form that is determined by the integrated effect of the wind field. Simulated and field data are compared. The motivation for the development of such a simulation model was the desire to evaluate various strategies for tracing odor plumes to their source, under identical conditions. The performance of such strategies depends in part on the instantaneous response of target receptors; therefore, the sequence of events is of considerable consequence and individual exemplar plume realizations are required. Due to the high number of required simulations, computational efficiency was critically important.     

基于RS和GIS的农业土地利用污染分析

农业已被确认为地表和地下水最主要的非点源污染源,而土地利用方式又是影响非点源污染的关键性因素。讨论了非点源污染与农业土地利用方式之间的关系,利用组件GIS技术,实现非点源污染负荷的定量计算及可视化分析。最后,以上海市松江区作为研究区域,对该区的污染情况进行了分析。结果表明,研究所提出的方法及开发的模块在非点源污染分析中基本上能满足要求,可以为环境建模提供必不可少的参数。     

北京市冬季大气化石源CO_2典型日变化的~(14)C示踪研究

城市作为化石源CO_2(CO_(2_(ff)))排放的热点区域.获得其大气CO_(2_(ff))浓度的日变化特征对于深刻理解城市地区CO_(2_(ff))的时空变化规律,进而制定合理的节能减排政策至关重要。本研究通过AMS-~(14)C技术,示踪了北京市冬季一个典型日变化事件中大气(CO_(2_(ff)))的变化过程,并探讨了其影响因素。本次日变化事件中大气δ~(13)CO_2的值为(-13.9±0.8)%。(-14.8‰—-12.7‰),△~(14)CO_2的值为(-151.6±51.3)‰((-214.2±2.9)‰-(-82.3±3.0)‰),CO_(2_(ff))浓度为104.4±44.0μL·L~(-1)(168.6±2.7-52.1±3.2μL·L~(-1)。CO_(2_(ff))浓度具有较大的曰变化,夜晚CO_(2_(ff))浓度明显高于白天,主要是由于夜间大气混合层高度较低、供暖消耗更多的化石燃料以及在东南风条件下因北京不利的扩散条件而使CO_(2_(ff))聚积。此外,在早晚高峰期间,观察到由于交通流量增加引起的较高CO_(2_(ff))浓度。同期PM_(2.5)浓度相似的日变化过程进一步验证了本次CO_(2_(ff))观测结果的可靠性。     

大气污染物及AQI时空特征分析——以山西省2015年上半年为例

根据2015年上半年山西省11个地级市PM 2.5、PM 10、NO 2、SO2、CO、O 3的日污染浓度监测数据及AQI值,分析其污染特征。结果表明:全省11市PM 2.5、PM 10超标率较高;NO 2、SO 2、CO、O 3超标率则较低;全省PM2.5/PM1 0的比值范围在0.367 7~0.718 9,且PM 2.5和PM 10之间存在较显著的线性关系;PM 2.5、PM 10、NO 2、SO 2、CO以及AQI监测值在1~6月份逐渐递减,O3则呈总体上升趋势;AQI达标天数比例范围在61.88%~85.08%,平均比例为71.42%,平均超标天数比例为38.58%,其中重度及以上污染天数比例为1.50%。     

怠速条件下汽车排气污染物在排气尾流中扩散特性的实验研究

通过实验的方法对怠速条件下汽车排气污染物在排气尾流中的扩散特性进行了研究.测定了怠速条件下汽车排气尾流中的污染物体积分数及其分布,并比较分析了3种不同类型汽车的污染物排放体积分数及其变化.实验结果表明,怠速时汽车排气尾流中的污染物体积分数按照近似指数函数的趋势迅速降低到接近大气背景值;不同类型汽车排气尾流中的污染物体积分数的差别非常明显;排气方向对汽车排放污染物的扩散及其分布具有重要的影响.研究工作可以为怠速工况下汽车排气污染物对周围环境的影响评价提供更多的有用信息.