南京市大气微生物调查及其动态研究

调查了南京市主要功能区大气微生物中常见种类的细菌和霉菌类,研究了细菌和霉菌类的生态分级和变化规律,比较了大气微生物与大气监测指标PM10、SO2、NO2的相关性。通过分析2000年10月至2001年8月6个功能区4个季节的监测结果,得出山西路监测点微生物数量最高,并且该点微生物中是以细菌为优势种,其次是霉菌属的马丁霉菌和耐渗透压霉菌。通过生理生化试验鉴定细菌和霉菌类,得出南京市大气微生物中细菌基本以微球菌属为主,霉菌以青霉属、曲霉属为主。大气微生物数量统计结果表明,南京市主要功能区微生物总量(均值)从高到低的顺序为:山西路(商业区)>中华门(交通区)>瑞金路(居住区)>迈皋桥(工业区)>玄武湖(对照点)>草场门(文教区)。大气化学监测指标PM10、SO2、NO2分析结果也表明大气微生物的数量变化与之呈一定的正相关关系,尤其与PM10关系更为密切。     

齐齐哈尔市不同功能区大气中溶血菌的污染

大气细菌是大气污染物的重要方面.在适宜条件下,可使人畜致病,农作物减产,危害甚大.目前,我国对大气细菌污染程度的研究多以空气中存在细菌数量多少表示,不能反映大气细菌污染的实际危害.本文依据某些溶血菌产溶血毒素可使血液琼脂培养基产溶血圈的特点,对齐市地区大气细菌污染程度进行了研究.     

校园空气微生物和悬浮物污染评价及相关性分析

在对广西师范大学育才校区教学区、宿舍区、运动场和交通区大气微生物和总悬浮颗粒物(TSP)进行监测的基础上,评价与分析了育才校区大气污染状况。依照中国科学院生态中心推荐使用的空气微生物评价标准,育才校区大气微生物污染轻微,其中交通区和运动场大气微生物含量相对较高,但都能达到清洁空气的标准;大气总悬浮颗粒物污染下午较严重,多数测定值超过了国家环境空气质量标准中的二级标准限值,而上午的测定值相对较低;四个功能区中TSP浓度值为交通区>运动场>教学区>宿舍区。上午空气中TSP浓度与细菌总数具有显著相关性,与霉菌总数相关关系不显著;下午TSP测定值与空气中细菌总数和霉菌总数的相关关系均不显著;校园空气中细菌总数和霉菌总数为极显著相关。     

兰州市不同季节大气微生物气溶胶粒径及分布特征研究

大气微生物对人类危害不仅与微生物气溶胶浓度和种类有关,而且大气微生物气溶胶粒径尺度大小及其分布特征也是重要的影响因素.在兰州市城关区选取不同环境功能区对其室外大气微生物气溶胶粒径(D,μm)大小及分布特征进行研究,结果表明,不同环境功能区大气细菌、霉菌和放线菌气溶胶粒度分布特征存在季节性分布差异,其中大气细菌气溶胶粒径...     

浅析气象因子对大气中低分子醛酮类有机物的影响

对广州市大气中低分子醛酮类有机污染物进行采样监测，并同步观测气象条件，分析气象因子与大气中低分子醛酮类有机物之间的相关性。结果表明：常规气象因子（温度、湿度、气压、风速等）对大气环境中醛酮类有机污染物的浓度有一定的影响。     

沉降法测定大气细菌粒子含量公式的检验

在沈阳市对文献［６］提出的由大气细菌粒子的沉降量计算大气细菌粒子含量的公式进行了检验．结果表明，在同泽小学由公式计算的大气细菌粒子的含量为３３２４个／ｍ３，Ａ·Ｓ采样器测定的大气细菌粒子的含量为３７９２个／ｍ３，二者之间的比值为０．９，ｔ＝０．７８５，Ｐ＞０．０５，两种方法得出的大气细菌粒子的含量没有明显差异，比传统的奥梅梁斯基公式有比较好的准确性和实用性．     

大气微生物与气象条件及大气污染物的灰色关联分析

根据大气微生物浓度、气象因子和大气污染理化因子的监测结果，应用灰色关联分析原理，分析研究大气微生物浓度与气象条件和大气污染物的关联程度，说明气象因子对各类微生物浓度的影响大于大气污染因子，特别是对耐高渗透压霉菌。     

天津市空气质量与气象因子相关分析

对采暖期间气象因子与空气质量的相关关系进行了系统分析.结果表明,天气形势对空气质量影响显著,两者相关性很好,可以针对不同天气型开展污染源治理.地面风场对空气质量的影响具有双重性,即风速越大,空气质量越好,但当风速达到7m/s时,可吸入颗粒物受开放源影响污染浓度会有所增加.大气稳定度的日变化影响空气质量的日变化;层结越稳定,空气污染越重,稳定层结一般出现在早晨4:00～8:00和晚间19:00～23:00.     

石河子市大气中氮氧化物与气象条件的关系

用实测数据分析了石河子市大气中ＮＯｘ与气温，湿度和风速等气象因子的关系，得出结论是气温升高，风速增强，使大气中ＮＯｘ浓度值降低，相对湿度在７０％～８０％之间，其ＮＯｘ浓度较高，为此，气象条件诸如水平风速，大气温度，湿度和大气层结构的稳定与否均大对气污染物浓度产生重要影响。     

北京市大气气态汞变化特征

采用Tekran 2537X大气汞分析仪在线测量北京市城区大气中气态元素汞(GEM,简称大气汞) 浓度,研究大气汞浓度随不同气象条件的变化特征。通过分析2016年10月—2017年9月大气汞监测数据发现,该监测点全年大气汞浓度为0.48～16.25 ng/m³,均值为(3.41±1.79)ng/m³。春季、夏季、秋季和冬季大气汞浓度均值依次为2.93 、2.95、4.27、3.37 ng/m³,其中,秋季大气汞浓度明显高于其他季节 。秋季大气汞浓度显著偏高可能由不利的大气扩散条件导致。大气汞夜间浓度显著高于白天浓度。同时,将大气汞与SO₂、CO及PM_2.5进行相关性分析,发现大气汞浓度变化趋势与SO₂、CO和PM_2.5呈显著正相关。结合风向和风速进行污染来源分析,得到该点位大气汞在西南和东北方向上受人为排放源影响较大。污染源类型分析表明,冬季大气汞与CO同源性强,主要来自本地供暖用煤。     

A generalized analytical solution for turbulent dispersion with inhomogeneous wind and diffusion coefficient

A technique is presented to solve analytically the turbulent diffusion equation for the concentration of a passive contaminant emitted from an elevated continuous source into the atmosphere. A generalized method of solution using Sturm–Liouville and WKB theories is developed to overcome difficulties due to the height‐dependent wind velocity and diffusion coefficient appearing in the diffusion equation. The method presented in this paper is able to derive an asymptotic expression for the concentration obtained from the solution of the atmospheric diffusion equation which involves explicitly inhomogeneous wind velocity and diffusion coefficient. The diffusion equation model derived from this method can be applied in a practical prediction of contaminant concentration in a turbulent atmosphere. This revised version was published online in August 2006 with corrections to the Cover Date.     

An analytic study of the effect of saltation on wind profiles

An analytic study of wind profiles above the saltation layer, in which the motion of uniform saltating grains of sand or snow occurs, is conducted. In this study, analytic solutions of the Ekman layer equation that governs the motion of air in a barotropic, neutral atmosphere are obtained in order to investigate the effects of the saltation on the airflow at large distance from a smooth surface. Solutions are derived subject to expressions of the eddy viscosity K(z) defined above the saltation layer up to the Ekman layer. The wind profiles and boundary layer interactions with the saltation process are discussed. With the assumptions that the eddy viscosity varies smoothly from the surface layer to the Ekman layer and K=0.4u _* z(1–z/h), the solutions are found to be consistent with bottom boundary conditions, specified by the velocity profile law outside the saltation layer. These solutions can be either used as an alternative to predict the saltation or used to test the sensitivities of the parameterization scheme designed to simulate dust emissions in a climate or general circulation model (GCM).     

Application of wind-profiling radar data to the analysis of dust weather in the Taklimakan Desert

The Urumqi Institute of Desert Meteorology of the China Meteorological Administration carried out an atmospheric scientific experiment to detect dust weather using a wind-profiling radar in the hinterland of the Taklimakan Desert in April 2010. Based on the wind-profiling data obtained from this experiment, this paper seeks to (a) analyze the characteristics of the horizontal wind field and vertical velocity of a breaking dust weather in a desert hinterland; (b) calculate and give the radar echo intensity and vertical distribution of a dust storm, blowing sand, and floating dust weather; and (c) discuss the atmosphere dust counts/concentration derived from the wind-profiling radar data. Studies show that: (a) A wind-profiling radar is an upper-air atmospheric remote sensing system that effectively detects and monitors dust. It captures the beginning and ending of a dust weather process as well as monitors the sand and dust being transported in the air in terms of height, thickness, and vertical intensity. (b) The echo intensity of a blowing sand and dust storm weather episode in Taklimakan is about ?1~10 dBZ while that of floating dust ?1~?15 dBZ, indicating that the dust echo intensity is significantly weaker than that of precipitation but stronger than that of clear air. (c) The vertical shear of horizontal wind and the maintenance of low-level east wind are usually dynamic factors causing a dust weather process in Taklimakan. The moment that the low-level horizontal wind field finds a shear over time, it often coincides with the onset of a sand blowing and dust storm weather process. (d) When a blowing sand or dust storm weather event occurs, the atmospheric vertical velocity tends to be of upward motion. This vertical upward movement of the atmosphere supported with a fast horizontal wind and a dry underlying surface carries dust particles from the ground up to the air to form blown sand or a dust storm.     

自然降尘与常规气象因子的相关分析

笔者整理统计了１９９２年至１９９４年逐月自然降水和与之相应的常规气象因子监测数据，找到了自然降尘的季节性分布规律。在此基础上，求得了自然降尘分别与月平均气温、月平均气压、月平均风速、月平均温度、月降水量、月蒸发量的相关系数，并进行了检验，为污染预报工作提供了科学依据。     

Airborne and allergenic fungal spores of the Karachi environment and their correlation with meteorological factors

Airborne fungal spores are well known to cause respiratory allergic diseases particularly bronchial asthma, allergic rhinitis, rhino-conjunctivitis and allergic broncho-pulmonary aspergillosis in both adults and children. In order to monitor and analyze airborne fungal flora of the Karachi environment, an aeromycological study was conducted using a Burkard 7-Day Recording Volumetric Spore Trap from January to December 2010. The data recorded from the Spore Trap was further analyzed for percent catch determination, total spores concentration, seasonal periodicities and diurnal variations. Cladosporium spp (44.8%), Alternaria spp. (15.5%), Periconia spp (6.1%), Curvularia spp (2.1%), Stemphylium spp (1.3%) and Aspergillus/Penicillium type (1%) emerged to be major components constituting more than 70% of the airborne fungal flora. Cladosporium, Curvularia and Stemphylium displayed a clear seasonal trend, while there were no clear seasonal trends for other fungal spore types. Diurnal variations were observed to be mainly having daytime maxima. Spearman Rank Correlation Coefficient analysis was conducted using various weather parameters. The various fungal types showed a negative correlation with heat index, dew point, wind velocity and wind chill. However, a positive correlation was found with humidity, rain and barometric pressure. In fact, Alternaria, Bipolaris and Periconia showed a negative correlation with temperature, while Cladosporium and Periconia showed a negative correlation with heat index, dew point, wind velocity and wind chill. The barometric pressure was positively correlated with Cladosporium. On the basis of these findings, it can be concluded that a number of fungal spores are present in the atmosphere of Karachi throughout the year, with certain atmospheric conditions influencing the release, dispersion, and sedimentation processes of some genera. It is expected that clinicians will use the identified fungal flora for diagnosis and treatment and/or adopt preventative measures for allergic individuals.     

Comparison of two dynamic measurement methods of odor and odorant emission rates from freshly dewatered biosolids

Odor and odorant emission rates from freshly dewatered biosolids in a dewatering building of a Water Reclamation Plant (WRP) are measured using the EPA flux chamber and wind tunnel methods. Experimental results are compared statistically to test whether the two methods result in similar emission rates when experiments are performed under field conditions. To the best of our knowledge the literature is void of studies comparing the two methods indoors. In this paper the two methods are compared indoors where the wind velocity and air exchange rate are pertinent field conditions and can be measured. The difference between emission rates of odor and hydrogen sulfide measured with the two methods is not statistically significant (P values: 0.505 for odor, 0.130 for H(2)S). It is concluded that both methods can be used to estimate source emissions but selection of the most effective or efficient method depends on prevailing environmental conditions. The wind tunnel is appropriate for outdoor environments where wind effects on source emissions are more pronounced than indoors. The EPA flux chamber depends on the air exchange rate of the chamber, which simulates corresponding conditions of the indoor environment under investigation and is recommended for estimation of indoor pollution sources.     

Statistical Analysis of Air Pollutants and Meteorological Parameters in Afyon, Turkey

In this study, the relation between sulfur dioxide (SO₂) and particulate matter (PM) concentrations periodically measured in the city of Afyon’s atmosphere with meteorological factors such as precipitation, humidity, temperature, wind velocity, and inversion were investigated. The mean values of SO₂ and PM concentrations measured during the winter months of October–March 1990–1999 were correlated with the meteorological parameters of the same period. Simple and multiple linear regression analysis were utilized to evaluate the contribution of meteorological variables. The statistical results show that the pollutants, i.e., SO₂ and PM are dependent upon humidity, temperature, and inversion at the 1% significance level; while the dependence of both pollutants with temperature is negative when those of humidity and inversion are positive. Two models in which temperature and inversion are dependent with multiple variables are recommended for predicting the contribution of meteorological parameters on SO₂ and PM. In addition, the relationship between humidity, temperature, and inversion with pollutants is also determined using nonlinear (polynomial) models.     

Turbulent Ventilation of a Street Canyon

A selection of turbulence data corresponding to 185 days of field measurements has been analysed. The non-ideal building geometry influenced the circulation patterns in the street canyon and the largest average vertical velocities were observed in the wake of an unbroken line of buildings. The standard deviation of vertical velocity fluctuations normalised by the ambient wind speed was relatively insensitive to ambient wind direction and sensor position, and it was usually larger than the corresponding 1-hour average velocity. Cross-correlations of spatially separated velocity measurements were small, and this suggests that most of the velocity fluctuations were fairly local and not caused by unsteady street vortices. The observed velocities scaled with the ambient wind speed except under low-wind conditions.     

Identification of air pollutant sampling period using horizontal dilution potential

A new model is proposed for estimating horizontal dilution potential of an area using wind data. The mean wind speed and wind direction variation are used as a measure of linear and angular spread of pollutant in the atmosphere. The methodology is applied to monitored hourly wind data for each month of 1 year for wind data collected at Vadodara, Gujarat and monthly dilution potential is estimated. It is found that there is a gradual variation of horizontal dilution potential over a year with limited dilution during post monsoon period i.e., October and November and a high dilution in pre monsoon period i.e., May and June. This information can be used to design air quality sampling network and duration of sampling for source apportionment study. Air pollutant sampling during high dilution period can be carried out for identifying urban and rural dust and wind blown dust from mining activity. Air pollutant sampling during low dilution period can be carried out for capturing large amount of particulate matter from anthropogenic sources like elevated stack of furnace.     

Modelling Equity: A Debate About Values

This paper discusses equity issues in relation to climate change. Models of long-term climate assessments study changes in relative prices. These changes lead to gains and losses for different economic actors and these consequences are held responsible for problems related to social acceptability. Policy recommendations issued by such models cannot be put into practice. Equity should be integrated into those models in order to make them more relevant for policy. This paper considers this problem in three parts.The first part shows that equity is only one aspect of the social dimension of sustainable development, which cannot be treated separately. It invites an understanding of complexity. Equity is also interrelated with the economic and ecological dimensions of sustainable development.The second part deals with the fact that different aspects of equity have to be taken into account and several concepts of equity co-exist. If only distribution of income is taken into account, equity can effectively be addressed through economic growth, but the specific characteristics of sustainable development are left out of the analysis.Therefore, the third part is a questioning of traditional modelling approaches and of the reasons why modelling should be carried out. The paper concludes with a short discussion about the normative content of any attempt to model climate change.