An Air Quality Impact Assessment for the Proposed Development of Stansted Airport

T he results of an air quality impact assessment conducted in 1980, for the proposed development of Stansted airport, Essex, to a capacity of 15 million passengers per annum, are presented. Air pollutant concentrations measured in the vicinity of the airport were found to be low in comparison to ambient air quality guidelines and also when compared with other airports and urban areas.
Atmospheric dispersion modelling to predict future emissions and ambient concentrations of air pollutants revealed that air quality standards would be unlikely to be infringed and that concentrations would be generally within the range of those measured at Gatwick airport in 1979.     

Volatile organic compounds in rural atmospheres of central Portugal

Atmospheric concentrations of volatile organic compounds were measured at two rural sites in central Portugal. The sites were chosen to be in line with the summer northwesterly sea breezes in order to study the evolution of the chemical composition of air masses during transport to inland areas. The most abundant non-oxygenated hydrocarbon in the ambient air was isoprene and the monoterpenes alpha-pinene, beta-pinene and 1,8 cineol. The maximum isoprene levels (6-7 ppb) were recorded at the most inland site, suggesting an enrichment of coastal air masses with biogenic emissions during transport over eucalyptus forests. Formaldehyde was the most prominent carbonyl compound in the atmosphere but acetaldehyde and acrolein were also abundant. Concentrations of carbonyl compounds had a tendency to be higher inland, particularly for glyoxal, methyl glyoxal, methyl vinyl ketone, metacrolein and pentanal. The observed increases indicate that carbonyls were produced by photochemical oxidation of biogenic hydrocarbons in aged air masses with coastal origin. Isoprene, monoterpenes and various carbonyls exhibited pronounced diurnal variations, which are explained on the basis of emissions from vegetation, oxidation pathways of biogenic hydrocarbons and meteorological conditions.     

Atmospheric volatile organic compound measurements during the 1996 Paso del Norte Ozone Study

Ambient air VOC samples were collected at surface air quality monitoring sites, near sources of interest, and aloft on the US (El Paso) and Mexican (Ciudad Juárez) side of the border during a six-week period of the 1996 Paso del Norte Ozone Study. Samples were collected at five sites, three on the US side and two on the Mexican side, during nine intensive operation days when high ozone levels were forecast for the area. Six other sites were sampled to characterize up-wind, down-wind and other emission sources. Samples for determining source profiles were collected for rush hour traffic, propane-powered bus exhaust, automobile paint shop emissions, propane fuels, and industrial manufacturing in Cd. Juárez and a refinery in El Paso. Most samples were collected in electro-polished stainless steel canisters for determination of C2 to C(10+) hydrocarbons by GC-FID. Carbonyl samples were collected on DNPH impregnated cartridges at three surface sites during aircraft flights and analyzed by HPLC. This paper presents the spatial and temporal characteristics of VOC species concentrations and compositions to examine the differences and similarities of the various locations and time periods. Overall surface, total non-methane hydrocarbon values ranged from 0.1 to 3.4 ppmC with the highest concentrations being recorded in the morning and evening at five vehicle-dominated sites, three in Cd. Juárez and two in El Paso. Toluene in El Paso samples and propane, which is used as a cooking and transportation fuel in Cd. Juárez, were the most abundant hydrocarbons. The most abundant carbonyls were acetaldehyde, acetone and formaldehyde.     

复杂地质条件下压实度检测方法的改进

结合控制填筑体压实度为机场施工过程中有效的质量监测手段这一事实，通过运用全料浮称法对广西河池机场填筑体进行了固体体积率室内试验，并对试验数据进行了分析，以确保机场地基稳定，从而提高了工程质量。     

Performance of ultraviolet photocatalytic oxidation for indoor air cleaning applications

Ultraviolet photocatalytic oxidation (UVPCO) systems for removal of volatile organic compounds (VOCs) from air are being considered for use in office buildings. Here, we report an experimental evaluation of a UVPCO device with tungsten oxide modified titanium dioxide (TiO2) as the photocatalyst. The device was challenged with complex VOC mixtures. One mixture contained 27 VOCs characteristic of office buildings and another comprised 10 VOCs emitted by cleaning products, in both cases at realistic concentrations (low ppb range). VOC conversion efficiencies varied widely, usually exceeded 20%, and were as high as approximately 80% at about 0.03 s residence time. Conversion efficiency generally diminished with increased airflow rate, and followed the order: alcohols and glycol ethers > aldehydes, ketones, and terpene hydrocarbons > aromatic and alkane hydrocarbons > halogenated aliphatic hydrocarbons. Conversion efficiencies correlated with the Henry's law constant more closely than with other physicochemical parameters. An empirical model based on the Henry's law constant and the gas-phase reaction rate with hydroxyl radical provided reasonable estimates of pseudo-first order photocatalytic reaction rates. Formaldehyde, acetaldehyde, acetone, formic acid and acetic acid were produced by the device due to incomplete mineralization of common VOCs. Formaldehyde outlet/inlet concentration ratios were in the range 1.9-7.2. PRACTICAL IMPLICATIONS: Implementation of air cleaning technologies for both VOCs and particles in office buildings may improve indoor air quality, or enable indoor air quality levels to be maintained with reduced outdoor air supply and concomitant energy savings. One promising air cleaning technology is ultraviolet photocatalytic oxidation (UVPCO) air cleaning. For the prototype device evaluated here with realistic mixtures of VOCs, conversion efficiencies typically exceeded the minimum required to counteract predicted VOC concentration increases from a 50% reduction in ventilation. However, the device resulted in the net generation of formaldehyde and acetaldehyde from the partial oxidation of ubiquitous VOCs. Further development of the technology is needed to eliminate these hazardous air pollutants before such a UVPCO device can be deployed in buildings.     

Concentration variations of pollutants in a work week period of an office

Indoor air quality problems for a typical office space were investigated. Continuous monitoring of concentrations was carried out for CO₂, CO, formaldehyde, and total hydrocarbons. It was found that the CO₂ concentration was at times above 2000 ppm and that for CO above 14 ppm. In addition, concentration levels of formaldehyde and total hydrocarbon were found to peak at midnight and indicated non-human sources. Partial opening of windows resulted in CO₂ concentration levels of 800 ppm or below. Ventilation rate measurements using trace gas decay method found that the air change rates were well below one air change per hour.     

宁波国际机场航显系统与楼宇自控系统的集成

为减少空调系统能耗，设计并实现了机场航显系统与楼宇自控系统的集成，这样可通过机场日常航班显示系统自动控制每一个登机口或侯机区域的空调机组与照明系统，既节能又提高了机场的自控水平。     

黎首都贝鲁特国际机场遭以军导弹袭击，引发大火

（本刊讯）黎巴嫩安全官员称，7月16日晚，以色列海军从军舰上向黎巴嫩首都贝鲁特发射了4枚导弹，击中了位于贝鲁特南部地区的拉菲克-哈裹裹国际机场，并导致其中的一座储油罐发生大火。这是以色列军方第二次对贝鲁特国际机场发动袭击。在此前的一次空袭中，贝鲁特国际机场的数条跑道被完全摧毁，导致附近的多个储油罐发生大火。     

硫酸盐渍土机场道面破坏机理研究

在分析盐渍土道面所处环境的基础上,对盐渍土道面破坏的机理进行了深入分析,通过上述分析指出道面下季节性水盐运动、飞机荷载以及施工质量是造成盐渍土机场破坏的主要因素。     

Air quality impacts of speed-restriction zones for road traffic

This study investigates the air quality impacts of six 20 mph zones implemented in the North West of England. A monitoring study has been undertaken to measure the concentrations of nitrogen dioxide (NO2) and benzene in ambient air both before and after the implementation of the zones. An emissions estimation and simple dispersion modelling study has also been undertaken using traffic survey data collected at the zones at corresponding periods. The ambient air quality measurements and the modelling predictions did not show any significant impacts after implementation of the 20 mph zones.     

道面水泥混凝土耐久性设计参数试验研究

水泥混凝土道面处于各种自然因素作用下,耐久性破坏现象经常发生,为保证道面的设计使用寿命得以实现,根据试验研究结果和道面的使用功能要求,提出不同地区的道面水泥混凝土抗冻等级、最大水灰比、最小水泥用量和含气量等参数,为机场水泥混凝土道面耐久性设计提供依据。     

非饱和土水气两相渗流有限元数值模型

根据非饱和土水气两相渗流理论,用Galerkin法建立了用以计算非饱和土水气两相渗流流场的有限元计算模型,编制了三维有限元计算程序,并介绍了该计算模型在可挥发污染物抽气曝气组合清除法中的应用。     

机场道面引气混凝土性能试验研究

机场道面混凝土是一种干硬性混凝土,与一般建筑工程使用的混凝土有较大区别.着重从含气量对机场道面混凝土的工作性和强度及抗冻性等方面的影响进行了试验.研究表明:抗折强度随含气量的增大而减小,但在3.5%～5.5%区间时,抗折强度下降较平缓;混凝土抗冻性随含气量的增大而提高,当含气最大于3%时,能够满足道面混凝土抗冻性要求.     

Polycyclic aromatic hydrocarbon (PAH) concentrations in ambient airborne particles from local traffic and distant sources; variation of the PAH profile

The temporal and spatial dependence of the PAH profile, i.e. the relative concentrations of polycyclic aromatic hydrocarbons, was investigated for ambient airborne particles during a period with moderate photochemical air pollution. The concentrations of 14 PAH were measured; they differed in volatility, sensitivity to atmospheric chemical conversion and contributing sources. Multivariate analysis (principal-component analysis and factor analysis) revealed that temporal dependence was predominantly determined by five factors clearly linked with volatility, reactivity and sources of the PAH, the first being by far the most important. The results, therefore, indicate that volatilization, conversion and a varying contribution of local sources were the major causes of the variation of the profile with time. The contribution of local sources was investigated by comparison of samples that were taken simultaneously at three different sites, one a background site and two sites downwind of traffic. A marked site dependence was found. The comparison suggested that the differences were not only determined by sources, but also by volatilization and/or conversion during residence of the particles in the air.     

The market size of a city-pair route at an airport

A model is developed for estimating the size of the market for a city-pair route at an airport from both the demand and supply sides of air transportation. The average airport access cost, average passenger delay cost, and average airline operating cost all either increase or decrease with an increase in the market size of a city-pair route at an airport, so the optimum market size can be determined from trade-offs among these costs. A nonlinear mathematical programming problem is formulated to determine the optimal number of passengers, the local service area of a city-pair market and to perform sensitivity analyses. The results show that long-haul services ought to be concentrated in one large airport, while short-haul services might be dispersed among many small airports. Improvements in the technology of the airport access mode or increases in the average income of the cities served can expand the market size and service area, but at a declining expansion rate. In metropolitan areas with high population density, airlines can operate more efficiently and distribute air services among more airports. City-pair markets with stable passenger demand, or markets served by airlines with efficient scheduling technology are shown to exhibit high cost efficiencies.     

国内大型机场新一代空管塔台设计的发展与问题浅析——以深圳机场空管扩建工程新建塔台为例

塔台是一类专业性很强的建筑,是机场建设的重要组成部分。近几年,国内大型机场的新塔台纷纷落成。本文通过笔者在深圳T3机场空管扩建工程新建塔台的工程实践,对国内大型机场塔台的发展趋势进行了介绍,并对设计中出现的一些问题进行了探讨。     

Ambient air measurements of aromatic and halogenated hydrocarbons at urban,rural and motorway locations

Concern over the carcinogenic properties of certain volatile organics in air, particularly benzene, has recently been expressed. Reductions in the lead content of perol in the United Kingdom and other European countries are predicted to change the concentrations of aromatic and halogenated hydrocarbons (1,2-dichloroethane and 1,2-dibromoethane) in ambient air. In order to provide baseline air quality data, prior to progressive reductions in the lead content of petrol, this study reports the results of a monitoring survey of ambient air concentrations of aromatic and halogenated hydrocarbon concentrations at urban, rural and motorway locations. A thermal desorption/gas chromatographic method analysing Tenax GC sampling tubes was utilised. Highest concentrations for benzene (9.7 ppb) and toluene (15.5 ppb) were measured at the urban site. The average benzene concentration is comparable with a proposed ambient air quality standard in the Federal Republic of Germany. Multiple regression analysis of nonmethane hydrocarbon and carbon monoxide air quality data demonstrated the importance of meteorological variables in defining measured concentrations. The toluene/benzene ratio (w/w) provided useful information in determining the degree of vehicle-related air pollution and supported evidence obtained from dynamometer studies of dealkylation of higher aromatics to benzene in engines operating at high speed and load at the motorway site.     

机场水泥混凝土道面施工中应注意的问题

在机场水泥混凝土道面施工过程中,发现劳务人员管理、现代水泥的质量控制、砂的级配控制、根据气候条件确定合理的施工工艺等方面问题比较突出,对机场道面的质量影响比较大,论文从这4个方面进行了阐述,为机场水泥混凝土道面施工提供参考。     

广州新白云国际机场飞行区道面混凝土监理实施要点

广州新白云国际机场是亚洲地区最大的机场之一,其道面混凝土具有面积大、厚度大、质量要求高等特点,施工难度非常大。本文结合广州新白云国际机场道面混凝土工程施工监理的经历,简要介绍高标准、高质量的机场道面混凝土工程监理实施要点。     

高原机场水泥混凝土道面各种裂缝质量控制

根据西部高原地区的气候特点及施工条件,通过红原机场实际案例,详细分析了机场水泥混凝土道面各种裂缝的产生原因,同时提出了相应的防治措施和处理方法,对保证机场施工质量具有一定现实意义。