隧道内空气污染物浓度预测方法

从纵向通风隧道内空气质量模式的解析解出发,纵向解析模式可方便地预测计算公路越江隧道内空气污染物浓度的分布。实例预测计算了上海市拟建隧道内CO浓度分布情况。     

乌鲁木齐市典型道路机动车行驶特征研究

本文对乌鲁木齐市区内快速路、主干道和次干道3种典型道路工作日和非工作日每小时的车辆实际行驶工况进行了测试,得到了乌鲁木齐市机动车在实际道路上的行驶工况;并对3种典型道路在不同时期(工作日和非工作日)不同时段(每小时)的平均速度、加减速度、行驶特征比例以及VSP进行比较分析。结果表明,不同道路及同一道路不同时段的行驶特征均不相同。因此,用单一的排放因子计算整个城市车队的排放清单尤其是建立时空分布的排放清单时会存在较大的不确定性。     

公路隧道中可吸入颗粒物化学组分特征研究

为了解公路隧道中可吸入颗粒物污染水平及化学组分特征，笔者于2006年9月1日在交通繁忙的石黄隧道中间及入口处进行了可吸入颗粒物（PM10）同步采样，并对样品进行了化学成分分析。根据PM10质量浓度监测以及样品的元素、OC＼EC及离子成分分析结果，对隧道口及隧道中的PM10的污染状况和化学成分特征进行了对比分析。PM10浓度监测和化学成分分析结果表明：石黄隧道环境空气中PM10质量浓度明显高于隧道外的浓度，隧道内PM10污染比较严重；隧道内PM10的离子浓度明显低于隧道外，而OC、EC浓度则又明显高于隧道外，另外其元素中Ca、Al、Si等浓度也明显高于隧道外，这些化学成分特征显示，隧道内的PM10主要来源于机动车尾气及道路扬尘。     

门头沟区燃气锅炉NO_x减排时空特征研究

本研究针对北京市门头沟区112台燃气锅炉开展了现场实测及调研工作,并对低氮改造后的NO_x减排时空特征开展了研究。本研究构建了基于Bootstrapping自助抽样法的采用不同低氮改造措施的燃气锅炉NO_x排放浓度及排放因子;采用采暖度日数法研究了燃气锅炉大气污染物排放的时间特征,并进一步利用自下而上的排放因子法研究了门头沟区燃气锅炉低氮改造的NO_x减排时空特征。研究发现,95%置信区间下执行80mg/m~3排放限值的低氮燃烧器及FGR技术的NO_x排放浓度分别为0.84～0.88g/m~3及0.82～0.88g/m~3;执行30mg/m~3排放限值的FGR技术及预混燃烧技术的NO_x排放浓度分别为0.33～0.36g/m~3及0.24～0.33g/m~3;未开展低氮改造的燃气锅炉的NO_x排放浓度为1.65～1.74g/m~3。     

成都市建筑扬尘扩散规律研究

为了研究成都市建筑扬尘的环境影响,通过对成都市范围内2016年不同施工阶段的建筑施工工地进行调研以及实地采样,统计了施工场地外界5～100m范围内建筑扬尘浓度变化,研究了不同施工源强下扬尘水平扩散的规律。结果表明,当施工扬尘浓度 0. 65 mg/m3时,水平扩散常数为916. 5 mg/m,等效逸散初始距离为29. 92m;当施工扬尘浓度在0. 15～0. 65 mg/m3之间时,水平扩散常数在1 066. 3～1 847. 6 mg/m之间,等效逸散初始距离在37. 2～61. 2m之间;当施工扬尘浓度≤0. 15 mg/m3时,水平扩散常数在411. 1～718. 3 mg/m之间,等效逸散初始距离在63. 6～95. 7m之间;施工扬尘浓度越大,等效逸散初始距离越短。扬尘浓度随距离的增加而递减,在80～100m处达到平衡;建筑扬尘扩散浓度与施工工地源强有关,源强越大,在相同距离、相同高度的建筑扬尘浓度越高,等效逸散初始距离越短,但水平扩散常数差异不大。     

MIKE21模型在排污口地表水影响预测方面的应用

在排污口设置过程中,往往由于其排放标准低于目标水体标准,导致在排放口附近形成超标区域,特别是对于大江大河,需要研究污染物排放影响范围以及对周边敏感目标的影响。以黄冈市某污水处理厂排污口为例,通过MIKE21水质模型预测污染物在长江水体内的影响范围、浓度大小以及对下游敏感点的影响程度,正常排放时COD、NH3-N不超标,事故排放时存在局部的超标但对下游7km较远处的取水口影响很小,可为排放口地表水影响预测提供参考。     

准东工业园区大气污染物对区域内敏感地带的影响研究

本文通过整理准东工业园区2014年度规模以上企业大气污染物排放清单,利用大气污染扩散模型,模拟2014年准东区域规模以上企业排放对周边敏感区域的影响。结果表明:2014年度规模以上企业排放的SO_2、NO_2对各个敏感点均存在影响。其中SO_2排放贡献最高的为北三电厂,贡献浓度为12.3μg/m~3,其次是五彩湾镇,贡献浓度为12.0μg/m~3,其余敏感点位贡献浓度均小于10μg/m~3。NO_2排放贡献最高的敏感点位亦为北三电厂,贡献浓度为8.72μg/m~3,其次是五彩湾镇,贡献浓度为8.69μg/m~3,其余敏感点位贡献浓度均小于8μg/m~3。现有企业为卡山保护局、五彩湾调蓄水库、奇台硅化木、五彩湾服务区等点位首要污染因素。     

华北地区CO2净排放比较优势时空特性分析

采用显示性比较优势理论,对2005-2010年我国华北地区5个省市人均CO2净排放和单位GDP CO2净排放的显示性比较优势做了分析;同时采用变异系数差异分析,结合空间自相关分析方法,对其空间格局和演变规律做了深入研究.研究发现,华北地区5省市人均CO2净排放高于全国平均水平.北京、天津、河北、山西4个省市出现下滑势头,而内蒙古自治区呈现大幅上升势头.山西单位GDP CO2净排放在全国最高,天津和北京低于全国平均水平.华北地区人均CO2净排放和单位GDP CO2净排放比较优势空间分别呈现负相关和正相关特性.     

长沙城区大气中二氧化碳浓度变化及与其它污染物相关性分析

利用长沙市城区2011年及2012年连续自动监测获得的CO2数据,两年的平均值为412．2×10^-6,高于世界本底站青海瓦里关5．6％,与临安、无锡相当,略高于乌鲁木齐,而低于北京、上海。冬季CO2浓度日小时变化呈现双峰形态,峰值出现在上午9时及晚上19时～21时。夏季日小时变化为单峰形态,峰值出现在上午8时。冬季CO2浓度日均值为420．3×10^-6,比夏季高3．4％。CO2除与O3呈负相关以外,与其它污染物均呈现显著性正相关,特别是与CO、NO、NO2、NOx、SO2的相关性最强,而与颗粒物（PM10、PM25）的相关性稍差。     

中国国际贸易中的内涵CO2排放及其空间特征

国际贸易中的内涵CO2排放成为全球气候变化谈判关注的热点.中国进出口贸易产品中的内涵CO2排放是导致中国温室气体排放总量显著增长的一个重要原因.研究表明,中国国际贸易中的内涵碳排放凸现"国外消费,国内污染"的典型特征;美、日、欧盟等OECD国家是中国国际贸易中内涵CO2净排放的主要集中区;非OECD中的亚洲国家是中国国际贸易中内涵CO2净排放的次集中区.据此提出:①应对全球气候变化应当考虑国际贸易导致的内涵碳排放;②中国出口产品的消费国应对中国的碳排放增长负有一定的责任;③构建消费型温室气体排放核算体系更能体现出减排的公平性;④发展低碳经济是中国从根本上减少温室气体排放的最有效措施.这一研究为重新界定中国温室气体排放和在国际气候谈判中充分争取公平性提供有利的佐证.     

Determination of VOC source signature of vehicle exhaust in a traffic tunnel

This study describes the methodology used to obtain the volatile organic compound (VOC) source signature of vehicle exhaust. To accomplish this, C(2)-C(9) VOCs were measured in a traffic tunnel located in Seoul, South Korea. The effect of VOC concentrations from the outside ambient air was considered in the determination of the source signature. To examine the effects of ambient air on VOC concentrations inside the tunnel, the ratio of propane to the total VOC concentrations was compared between the entrance and middle sites in the tunnel. Propane was used as a standard not only because of its insignificant contribution to vehicle exhaust gas, but also the fact that propane is the most abundant VOC in the atmosphere of Seoul. The ratio of propane to the total VOC concentrations was higher at the entrance site than at the middle location by, on average, 60%. This suggests that ambient air affects the inside tunnel air to a greater extent at the entrance site as compared to the middle site. The contribution of ambient air to the air inside the tunnel at the entrance location varied from 30% to 67%, with an average of 55%. This is 1.5 times higher than the value measured at the middle location, which ranged from 20% to 48%, with an average of 36%. This shows that ambient air substantially affects the inside air of the tunnel. Excluding the effects of ambient air on the air inside the tunnel can provide an improved chemical composition for vehicle exhaust using tunnel measurements. We believe that the concentration difference between the two sites within the tunnel provides a more accurate chemical composition of vehicle exhaust as compared to that obtained from a measurement taken at only one point inside the tunnel.     

应用CALINE4模式估算机动车排放污染物的浓度——以济南市主干道为例

随着经济的快速发展,机动车排气污染已成为我国城市空气污染的重要来源,而且在一定时段,机动车排气污染已成为空气污染最主要的污染源之一。以济南市经十路为例,采用实地调查的方法,得出各时段的车流量,选用大气环评助手EIAA中的CALINE4模式对机动车尾气中的主要污染物CO、NOx、THC的排放浓度进行估算,得出3种污染物CO、NOx、THC最大值均出现在7:00—8:00之间,最小值均出现在12:00-13:00之间,排放强度由大到小为:CO、THC、NOx。     

城市居民交通方式选择及其影响因素分析——以南京市为例

随着我国城市化水平的提高,城市交通能源消费占总能源消费的比重逐渐增大,交通方式选择及其影响因素研究引起广泛关注。本研究通过调查南京居民出行交通方式,并通过多项logit模型(multinomial logit model),探究影响居民交通选择的关键因素,为城市交通政策的制定提供科学依据,并根据估算结果分析不同政策下交通方式改变带来的节能减排效应。结果显示:出行特性(如出行距离)、出行者的个人特征(如性别、年龄、职业)与出行者的家庭特征(如是否有私家车,是否有小孩)都对交通方式选择有显著影响。如果通过有效的交通政策引导,使私家车出行转变为轨道交通出行,南京每天大约可减少1573.5吨碳排放。     

The connecticut indirect source review: A methodology and model for evaluating CO concentrations

The body of information presented in this paper is directed to air pollution engineers who are concerned with the effect of indirect sources on ambient concentrations of carbon monoxide (CO). Data taken under controlled conditions are used to empirically derive and calibrate a model for predicting CO concentrations in the vicinity of roadway intersections and other points of possible vehicular congestion. Since the predicted free flow CO contribution of vehicles traveling at normal road speeds is relatively low, it is concluded that idling vehicles at points of congestion are the major cause of CO violations, and that state and federal programs should place more emphasis on relieving congestion and reducing idling emission rates in new vehicles.     

Greenhouse gas emissions during cattle feedlot manure composting

The emission of greenhouse gases (GHG) during feedlot manure composting reduces the agronomic value of the final compost and increases the greenhouse effect. A study was conducted to determine whether GHG emissions are affected by composting method. Feedlot cattle manure was composted with two aeration methods--passive (no turning) and active (turned six times). Carbon lost in the forms of CO2 and CH4 was 73.8 and 6.3 kg C Mg-1 manure for the passive aeration treatment and 168.0 and 8.1 kg C Mg-1 manure for the active treatment. The N loss in the form of N2O was 0.11 and 0.19 kg N Mg-1 manure for the passive and active treatments. Fuel consumption to turn and maintain the windrow added a further 4.4 kg C Mg-1 manure for the active aeration treatment. Since CH4 and N2O are 21 and 310 times more harmful than CO2 in their global warming effect, the total GHG emission expressed as CO2-C equivalent was 240.2 and 401.4 kg C Mg-1 manure for passive and active aeration. The lower emission associated with the passive treatment was mainly due to the incomplete decomposition of manure and a lower gas diffusion rate. In addition, turning affected N transformation and transport in the window profile, which contributed to higher N2O emissions for the active aeration treatment. Gas diffusion is an important factor controlling GHG emissions. Higher GHG concentrations in compost windrows do not necessarily mean higher production or emission rates.     

An Application and Evaluation of the CAL3QHC Model for Predicting Carbon Monoxide Concentrations from Motor Vehicles Near a Roadway Intersection in Muscat,Oman

The CAL3QHC model was used to predict carbon monoxide (CO) concentrations from motor vehicles at an existing urban intersection (Star Cinema in Muscat area, Oman). The CO concentrations predicted from the model were compared with those measured in the field. Predicted average CO concentrations were found to compare favorably with measured values obtained at all eight receptors considered within the modeled intersection. In general, the comparison indicates good agreement with some underprediction for CO. For receptor 6, the model overpredicts the average CO concentration. This overprediction is associated with the presence of trees and green area in the location of receptor 6. In general, the measurements and the model results indicated that the highest CO concentrations were found to occur close to the intersection and, hence, a decrease in the concentration levels was seen as the distance from the road increased. The results indicated that the levels of CO were well below the ambient air quality standard and that probably no health risk was present in areas adjacent to the star cinema intersection. However, the predicted worst-case 1-h CO concentrations assuming inversion atmospheric stability conditions (class F) and wind speed of 1 m/s indicated that the levels of CO were close to or higher than the Omans National Ambient Air Quality Standards (NAAQS) value of 35 ppm at all receptors considered. The results of this study are useful in transport development and traffic management planning.Published online.     

旅游景区的低碳交通模式研究

景区内部交通构成旅游景区碳排放的主体，创建低碳旅游景区必然要走低碳交通之路。旅游景区的低碳交通建设是一个系统工程。从低碳景区创建角度出发，对景区内几种典型交通方式的碳排放情况进行定量分析和初步比较，从交通工具的选择与改进、交通站点的合理设置、景区道路的科学规划、运营管理的技术引入等方面构建旅游景区的低碳交通模式，为相关景区选择低碳化的交通方式提供依据。     

Sensitivity analysis of ground-level ozone concentration to emission changes in two urban regions of southeast Texas

Air pollutant emission is one of the predominant factors affecting urban air quality such as ground-level ozone formation. This paper assesses the impact of changing emission inventory scenarios, based on combinations of point, mobile, area/non-road and biogenic sources, on the tropospheric ozone concentration in two southeast Texas urban areas, i.e. Houston-Galveston and Beaumont-Port Arthur, during the rapid ozone formation event (ROFE) on August 25, 2000. The EPA's Community Multiscale Air Quality (CMAQ) modeling system with 1999 national emission inventory (NEI99) estimates and updated SAPRC99 chemical mechanism are used in the sensitivity analysis for twelve different emission scenarios. Based on model results, it is found that the point source emission of NOx and VOC contributes the greatest ozone peak in the ROFE. Removing Texas point sources of VOC and NOx emission from the inventory results in a reduction in peak O3 concentration by 128 and 70 ppbv in Houston urban area, respectively. Similar but less drastic impact from point source is also observed in the Beaumont-Port Arthur area. The effect on peak ozone concentration due to mobile, area and non-road sources emissions are less significant compared to that of point source emission. Reducing VOC emission appears to be more effective than reducing NOx emission in lowering peak O3 concentration in the studied region. Although biogenic emission can contribute up to 37 ppbv of peak ozone level over a large area, the affected area is away from the urban region of concern, and should not be the main cause for O3 non-attainment in the two urban areas. Removing CO emission from mobile sources does not lead to significant reduction (< 1 ppbv) in ozone concentrations. The modeled data also show that the transport of O3 precursors from adjacent states can cause a significant ozone plume near Beaumont due to its proximity to the state border based on the conditions during the August 25, 2000 O3 episode.