Indoor and outdoor personal exposure to benzene in Athens, Greece

OBJECTIVE: To evaluate the exposure of urban inhabitants to atmospheric benzene in Athens, Greece. METHODS: Fifty non-smoker volunteers from selected occupational groups and their homes were monitored by passive air samplers for six 5-day periods during a year. An activity diary was completed during each sampling period and relevant data were collected by a questionnaire at the beginning of the study. Additional data on urban levels on benzene were also available. RESULTS: Average benzene home and personal levels in six monitoring campaigns varied between 6.0-13.4 and 13.1-24.6 microg/m(3), respectively. Urban levels varied between 15.4 and 27.9 microg/m(3) with an annual mean of 20.4 microg/m(3). Wind speed seems to determine largely home levels and personal exposure. Proximity to busy road holds also an important influence on indoor benzene levels. Adjusted for seasonal or climate variation, other significant prognostic factors of personal exposure were home levels, total time spent outdoors and transportation mean. Time spent outdoors explains the strong relationship between occupation and personal levels of exposure. Wind had similar effect in clearing indoor and urban pollution in Athens; lessen personal exposure and home levels about 2-2.5 microg/m(3) per 1 m/s increase in speed. CONCLUSIONS: Factors related to climate (use of non-absorbent materials for wall and floor covering and frequent ventilation) might be one explanation for homes' high clearing rate. Our exposure pattern, which suggests that outdoors work give the greater contribution to benzene exposure of Athens citizens, is uncommon in northern towns of Europe. Policy makers have to take in account these differences in establishing guidelines for ambient benzene exposure.     

An evaluation of three biometeorological indices for human thermal comfort in urban outdoor areas under real climatic conditions

Three biometeorological indices were examined in terms of their potential to describe the actual thermal sensation as this is experienced by humans at areas with different climatological characteristics. The thermal comfort scales, as derived from using Physiological Equivalent Temperature (PET), the Temperature-Humidity Index (THI) and the wind chill index (K), were compared to Actual thermal Sensation Votes (ASV) data as expressed on a 5-point scale. These data were collected by surveys that covered all four seasons of the year and were conducted in seven European cities (Athens, Thessaloniki, Milan, Fribourg, Cambridge, Sheffield and Kassel). Results show that, for any given ASV class, the corresponding classes calculated according to PET, THI and K, present a strong correlation with the climatic mean temperature of the survey site, which in turn leads to misclassification of the thermal sensation. Accordingly, an effort was made to apply an adjustment to the indices based on climatic mean temperature. Only small improvements were observed on the performance of the indices.     

Use of outdoor spaces and microclimate in a Mediterranean urban area

This paper presents some of the findings of the European project, RUROS, concentrating on the effect of microclimatic conditions on the use of open spaces in an urban Mediterranean environment. The findings confirm that there is a strong relationship between microclimatic conditions and use of open spaces. Regarding the users of open spaces, a sensitivity to the summer heat was apparent for the age category >65$>65$. The spatial distribution of the interviewees demonstrates that in summer, visitors prefer to sit in shaded areas, whereas in autumn and winter sunlit areas are more popular. Observations of the use of space revealed that air temperature and solar radiation were found to be the most dominant parameters in relation to the use of space, with wind speed and relative humidity having a weak effect. In general, people prefer shaded areas at higher air temperatures. However, as high air temperature is a factor contributing to discomfort, overall presence is reduced when air temperature rises significantly. The preference of sun, differs from season to season, depending on the activities taking place in the areas (either designated or not). The diurnal pattern of the use of space also reveals a strong dependency on meteorological parameters. Regarding the time of maximum attendance, this is found in the evening during summer, while there is a transition of the time of maximum attendance towards noon as the season progresses from summer to winter. Daytime attendance figures of autumn and winter are 300–400% higher than in the summer. The need open spaces cover and the social ties provided may also be traced by analysing the social composition of the interviewees and the reasons bringing them in the space.     

城市区域小气候对建筑设计的影响

建筑师在建筑设计的过程中对当地气候条件因素的考虑是必不可少的一环，但气象数据的更新远跟不上城市规模和城市气候环境的变化，尤其对于特大型都市来说，同一时间内城市不同区域已出现了气象数据上较大的差异，建筑师或规划师若依然采用旧有的建筑气象数据来进行设计，则建筑与环境之间必然存在不协调之处。这是设计人员应留意的地方。     

A comfortable wind climate for outdoor relaxation in urban areas

All sorts of urban outdoor areas have been designed for relaxation. One important condition for relaxation is a pleasant climate. Sun, wind and temperature are important components of this climate.

The velocity of the wind in particular offers possibilities for regulation by application of measures for providing shelter. In the Dutch climate, it is found that a reduction of wind velocity to 1.5 m s−1 or less would remove some share of the negative effects of wind on the relaxation function of the city.     

城镇住宅区户外环境设计初探

指出住宅区户外环境设计面临的新情况、新任务,分析了老年人、残疾人的体能及心态特征,从住宅区户外活动空间的设计,步行空间设计等方面探讨了如何进行户外环境设计,以期创建优美和谐的无障碍住区环境。     

奥纳西思文学美术馆,雅典(希腊)

设计任务:包括一座可容纳1000人的歌剧院、一座可容纳200人的音乐厅、一间可容纳200人的露天阶梯教室,一个图书馆,一个餐厅,一个展览厅. 　　奥纳西斯文学美术馆由建在玻璃底座上的达索大理石构成,外形简洁大方、呈半透明状.墙体立面的近景与远景皆呈现出透明与半透明的透视效果,特殊的建材组合使整个建筑充满动感.不规则的实体石材与规则透明的玻璃体取得了和谐的平衡.……     

Experimental investigation on the thermal comfort in the city: relationship with the green areas,interaction with the urban microclimate

This paper describes the methodology developed by the authors to analyze the influence of “green areas” on the urban comfort of the city of Valencia, taken as the prototype of Mediterranean cities. Based on the analysis of its climatological conditions, different “comfort indices” are used to study several characteristic districts of the city of Valencia which globally define the urban behavior of this city. Some of these comfort indices have been formulated in terms of the existing green areas; the results obtained permit to know the surface of the green areas required by each district to be considered theoretically comfortable. This methodology can be very useful to urban planners in the design and distribution of green areas in cities.     

局部热暴露对人体热反应的影响研究(1):局部热感觉对全身热感觉的影响

随机选取30名男性受试者,在中性偏热的房间中,局部冷气流分别作用于脸部、胸部和背部,采用问卷调查的方法以一定的时间间隔记录了受试者身体各个部位的局部热感觉和全身热感觉。结果表明,局部热暴露在改变暴露部位和全身的热感觉的同时,也显著改变了非暴露部位的热感觉,据此提出了基于影响因子的分析方法和全身热感觉的预测模型。     

Experimental study of human thermal sensation under hypobaric conditions in winter clothes

Hypobaric conditions, with pressures about 20-30% below that at sea level, are often experienced at mountain resorts and plateau areas. The diffusive transfer of water evaporation increases at hypobaric conditions whereas dry heat loss by convection decreases. In order to clarify the effects of barometric on human thermal comfort, experiments are conducted in a decompression chamber where the air parameters were controllable. During experiments, air temperature is set at a constant of 20, air velocity is controlled at <0.1 m/s, 0.2 m/s, 0.25 m/s, and 0.3 m/s by stages. The barometric condition is examined stepwise for 1atm, 0.85 atm and 0.75 atm of simulated hypobaric conditions, which is equivalent to altitude of 0 m, 1300 m, and 2300 m respectively. Ten males and ten females in winter clothes participate in the experiments. Thermal sensations are measured with ASHRAE seven-point rating scales and skin temperatures were tested at each altitude. The main results are as follows: when the altitude rises, (1) the mean thermal sensation drops; (2) people become more sensitive to draught and expect lower air movements; (3) no significant change of mean skin temperature has been found. The results of the present study indicate that hypobaric environment tends to make people feel cooler.     

PM10 composition during an intense Saharan dust transport event over Athens (Greece)

The influence of Saharan dust on the air quality of Southern European big cities became a priority during the last decade. The present study reports results on PM₁₀ monitored at an urban site at 14 m above ground level during an intense Saharan dust transport event. The elemental composition was determined by Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF) for 12 elements: Si, Al, Fe, K, Ca, Mg, Ti, S, Ni, Cu, Zn and Mn. PM₁₀ concentrations exceeded the EU limit (50 μg/m³) several times during the sampling period. Simultaneous maxima have been observed for the elements of crustal origin. The concentrations of all the elements presented a common maximum, corresponding to the date where the atmosphere was heavily charged with particulate matter permanently for an interval of about 10 h. Sulfur and heavy metal concentrations were also associated to local emissions. Mineral dust represented the largest fraction of PM₁₀ reaching 79%. Seven days back trajectories have shown that the air masses arriving over Athens, originated from Western Sahara. Scanning Electron Microscopy coupled with Energy Dispersive X-ray analysis (SEM-EDX) revealed that particle agglomerates were abundant, most of them having sizes < 2 μm. Aluminosilicates were predominant in dust particles also rich in calcium which was distributed between calcite, dolomite, gypsum and Ca-Si particles. These results were consistent with the origin of the dust particles and the elemental composition results. Sulfur and heavy metals were associated to very fine particles < 1 μm.     

Indoor and outdoor concentrations of ultrafine particles in some Scandinavian rural and urban areas

The concentration of ultrafine particles (0.01 to greater than 1 microm) was measured in some rural and urban areas of Sweden and Denmark. The instruments used are handheld real-time condensation particle counters, models CPC 3007 and P-Trak 8525, both manufactured by TSI. Field measurements in Sweden were conducted in a few residential and office buildings, while in Denmark the measurement sites comprised two office buildings, one of them located in a rural area. The concentration of UFPs was measured simultaneously indoors and outdoors with condensation particle counters. The results revealed that the outdoor-generated particle levels were major contributors to the indoor particle number concentration in the studied buildings when no strong internal source was present. The results showed that in office buildings, the UFP concentrations indoors were typically lower and correlated fairly well to the number concentration outdoors. The determined indoor-outdoor ratios varied between 0.5 and 0.8. The indoor levels of UFPs in offices where smoking is allowed was sometimes recorded higher than outdoor levels, as in one of the Danish offices. In residential buildings, the indoor number concentration was strongly influenced by several indoor activities, e.g., cooking and candle burning. In the presence of significant indoor sources, the indoor/outdoor (IO) ratio exceeded unity. The magnitude of UFP concentrations was greater in the large city of Copenhagen compared to the medium-size city of Gothenburg and lowest at more rural sites.     

Comfort in urban spaces: defining the boundaries of outdoor thermal comfort for the tropical urban environments

With rapid urbanisation, often without climate responsive guidelines, cities in the Tropics are progressively falling short of sustaining outdoor life. While at the building level such inadvertent climatic modifications have lead to a remarkable demand on the urban energy resources. The rationale for developing a thermally desirable outdoor ambience in such a context has implications that go beyond the requisites of urban design and well into the design of buildings. In order to re-establish and sustain life outdoors it is important that we try to make urban spaces comfortable as far as the ambient climate permits. In order to ascertain conditions of comfort for outdoor spaces we need to define comfort for outdoors. This paper presents findings on outdoor comfort based on field investigations conducted in Dhaka, a city in the wet-Tropics. Findings from a survey conducted on a large number of randomly selected people from urban spaces are presented. The findings include factors affecting comfort outdoors for Dhaka and a comfort regime based on environmental parameters for urban outdoors is presented. Interestingly, comfortable ambient climate leads to comfortable indoor environment particularly with regard to free running buildings. With regard to mechanically controlled indoor environments a comfortable outdoor produces lesser strain on energy environment relationship. By defining conditions of comfort for outdoor environments an important step towards achieving sustainability of our urban environments can be made.     

Evaluating thermal comfort conditions and health responses during an extremely hot summer in Athens

In summer 2007, in the city of Athens, Greece, extremely high air temperatures were recorded, inducing heat discomfort conditions in the urban environment. Four biometeorological indices were calculated in order to evaluate human thermal sensation and thermal comfort: Actual Sensation Vote (ASV), Thermal Sensation-Ginovi method (TS), Discomfort Index (DI) and Heat Load Index (HL). Data included measurements of ambient temperature, temperature of the surrounding ground surface, relative humidity, air pressure, wind velocity and solar radiation obtained from National Observatory of Athens (NOA) station. During this period the daily number of patients probably affected by heat in emergency department units of cardiac clinics of four public general hospitals in Athens was recorded. The results revealed high values of DI and HL indices, demonstrating severe heat stress conditions during the last ten day period of June and July, while the ASV tends to classify too many cases into the comfort zone compared to TS, DI and HL. The statistical analysis revealed a negative relationship between the number of heat affected patients and the estimated indices values.     

On the use of bioclimatic architecture principles in order to improve thermal comfort conditions in outdoor spaces

The present paper describes a process for designing and applying several techniques based on bioclimatic architecture criteria and on passive cooling and energy conservation principles in order to improve the thermal comfort conditions in an outdoor space location located in the Great Athens area. For that reason, the thermal comfort conditions in 12 different outdoor space points in the experimented location have been calculated using two different thermal comfort bioclimatic indices developed to be used for outdoor spaces. The used indices were the following: (a) “Comfa”, which is based on estimating the energy budget of a person in an outdoor environment and (b) “thermal sensation”, based on the satisfaction or dissatisfaction sensation under the prevailing climatic conditions of the outdoor spaces. Calculations were performed during the summer period and two different scenarios of the constructed space parameters have been considered. The first scenario consists of a conventionally constructed space, while the second one includes various architectural improvements according to the bioclimatic design principles. The two bioclimatic indicators were used for calculating the outdoor thermal comfort conditions in the above-mentioned outdoor space locations for both scenarios and the effect of the bioclimatic design architectural improvements on the human thermal comfort sensation was presented and analysed.     

Mapping and classification of direct flood impacts in the complex conditions of an urban environment. The case study of the 2014 flood in Athens,Greece

Urban flooding is a gradually increasing problem as the urban population expands into floodplains. In urban environments, flood vulnerability is significantly increased as a more concentrated population and assets makes flooding costly and challenging, in terms of impact estimation. This work focuses on mapping and classifying impacts after the catastrophic 2014 flood in Athens, Greece. The study proposes a method for classifying flood effects into four categories including: the natural and built environment, mobile objects and human population, organized in five classes of increasing severity, i.e. minor, weak, moderate, strong and extreme. Flood effects are grouped based on the qualitative nature of the recorded effects, allowing the development of an impact-severity map. Mapping of the 2014 flood effects indicated specific locations where the severity of impacts was distinctively higher than others, providing a holistic overview of the flood’s effects and highlighting the usefulness of the approach in future flood protection planning.     

Exposure to carbon monoxide in the Athens urban area during commuting

An extensive survey has been designed to provide detailed information on carbon monoxide (CO) concentration in the main transport modes and along heavy traffic routes in the Athens urban area. Specifically the study identifies the main factors affecting CO exposure during commuting. Several portable, electrochemical CO monitors (Solomat's MPM4100), were used to record the in-vehicle CO concentrations every 15 s. Measurements were performed during rush hour periods. Field monitoring was conducted in summer 1998 and winter 1998-1999. Exposure estimates were compared to WHO guidelines. The findings showed that the mean CO level over trips of 30 min was 21.4 ppm for private car against 10.4, 9.6, 4 and 11.5 ppm for bus, trolley, electric train and pedestrians, respectively. Transport mode, route, monitoring period and season had a significant influence on the measured CO concentrations. The study points out the importance of microenvironmental monitoring, instead of using fixed-site data in assessing commuter's CO exposure.     

A modeling study for evaluating passive cooling scenarios in urban streets with trees. Case study: Athens,Greece

The present work investigates the causes of the variability in air temperature patterns among urban streets with trees in Athens, as obtained from in situ measurements, in a suburb area and in the city center. Urban variables studied are: the extent of tree canopy coverage, traffic load, surfaces albedo modification, street deepening aspect and the street’s ventilation. The thermal effect of each variable is estimated by simulations using the Green CTTC analytical microclimate model. The model was first validated with measurements data and consequently used to study the effect of the various urban variables in attenuating the high values of air temperature within the studied streets considering two feasible scenarios for each of the examined streets. Model results revealed that the total attenuation effect in reducing the air temperatures inside the streets may reach as much as 5 K at noontime with a daily average cooling of 3 K. Further, the study demonstrates the potential use of microclimate modeling in assessing the merits of proposed passive cooling strategies in urban streets.     

浅议城市住区儿童日常户外活动场所规划设计

通过分析儿童日常生活户外活动场所的规划设计应该注意的问题,探讨了城市住区儿童日常生活户外活动场所规划设计方法,以期在实际的城市住区规划设计中有一定的指导意义。