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1.
This study reports on a numerical investigation of transport behavior of indoor airflow and size-dependent particulate matter (PM) in multi-room buildings. An indoor size-dependent PM transport approach, combining the Eulerian large-eddy simulation of turbulent flow with the Lagrangian particle trajectory tracking, was developed to investigate indoor airflow pattern and PM1/PM2.5/PM10 removal efficiency in naturally ventilated multi-room buildings. A displacement ventilation with a measured indoor PM10 profile in Taipei Metropolis as the initial condition was carried out to characterize spatial and temporal variations of indoor PM1/PM2.5/PM10 removal behavior. The effects of indoor airflow pattern on particle transport mechanisms, e.g., deposition, suspension, migration and escape, were analyzed. Two comparison scenarios, which considered the effects of no indoor partition and different air change rate, respectively, were also conducted. In comparison with the effectiveness of PM1/PM2.5/PM10 removal, the simulated results showed that coarse particles were easier to be removed out of the building than fine particles. Natural ventilation was not an effective way to remove fine particles such as PM1 and PM2.5 in a multi-room building. Indoor partitions can impede 12% of the mean streamwise velocities and significantly increase 30-50% turbulence intensities. However, indoor partitions increased particle deposition and decreased particle escape. As a result of the two opposite particle removal mechanisms, i.e., deposition and escape, the impact of indoor partitions on PM1/PM2.5/PM10 removal behavior was not as significant as the results of airflow velocities. PRACTICAL IMPLICATIONS: This work developed a computational fluid dynamics technique to investigate indoor airflow patterns and PM1/PM2.5/PM10 removal ability in ventilated multi-room buildings. The results of this paper can help to identify adequate PM1/PM2.5/PM10 cleaning procedure and provide useful size-dependent PM control strategy in multi-room buildings. 相似文献
2.
Role of Saharan dust in the relationship between particulate matter and short-term daily mortality among the elderly in Madrid (Spain) 总被引:1,自引:0,他引:1
Background
Saharan dust outbreaks are a common phenomenon in the Madrid atmosphere. The current Directive 2008/50 CE governing air quality in European cities, draws no distinction between which particulate matter (PM10, PM2.5 or PM10-2.5) would be the best indicator on days with/without Saharan dust intrusions. This study sought to identify the role played by Saharan dust in the relationship between particulate matter (PM10, PM2.5 and PM10-2.5) concentrations and daily mortality among the elderly in the city of Madrid.Methods
We conducted an ecological longitudinal time-series study on daily mortality among the over-75 age group, from 2003 to 2005. Poisson regression models were constructed for days with and without Saharan dust intrusions. The following causes of daily mortality were analysed: total organic causes except accidents (International Classification of Diseases-10th revision (ICD-10): A00-R99); circulatory causes (ICD-10: I00-I99); and respiratory causes (ICD-10: J00-J99). Daily mean PM10, PM2.5 and PM10-2.5 levels were used as independent variables. Control variables were: other ambient pollutants (chemical, biotic and acoustic); trend; seasonalities; influenza epidemics; and autocorrelations between mortality series.Results
While daily mean PM2.5 concentrations in Madrid displayed a significant statistical association with daily mortality for all the above causes on days without Saharan dust intrusions, this association was not in evidence for PM10 or PM10-2.5 in the multivariate models. The relative risks (RRs) obtained for an increase of 10 μg/m3 in PM2.5 concentrations were: 1.023 (1.010-1.036) for total organic causes; 1.033 (1.031-1.035) for circulatory causes; and 1.032 (1.004-1.059) for respiratory causes. On Saharan dust days, a significant statistical association was detected between PM10 (though not PM2.5 or PM10-2.5) and mortality for all 3 causes analysed, with RRs statistically similar to those reported for PM2.5.Conclusions
The best air quality indicators for evaluating the short-term health effects of particulate matter in Madrid are therefore PM10 concentrations on days with, and PM2.5 concentrations on days without Saharan dust outbreaks. This fact should be taken into account in a European Directive regulating ambient air quality in almost all countries in the Mediterranean area. 相似文献3.
Sources and properties of non-exhaust particulate matter from road traffic: a review 总被引:11,自引:0,他引:11
While emissions control regulation has led to a substantial reduction in exhaust emissions from road traffic, currently non-exhaust emissions from road vehicles are unabated. These include particles from brake wear, tyre wear, road surface abrasion and resuspension in the wake of passing traffic. Quantification of the magnitude of such emissions is problematic both in the laboratory and the field and the latter depends heavily upon a knowledge of the physical and chemical properties of non-exhaust particles. This review looks at each source in turn, reviewing the available information on the source materials and particles derived from them in laboratory studies. In a final section, some of the key publications dealing with measurements in road tunnels and the roadside environment are reviewed. It is concluded that with the exception of brake dust particles which may be identified from their copper (Cu) and antimony (Sb) content, unequivocal identification of particles from other sources is likely to prove extremely difficult, either because of the lack of suitable tracer elements or compounds, or because of the interactions between sources prior to the emission process. Even in the case of brake dust, problems will arise in distinguishing directly emitted particles from those arising from resuspension of deposited brake dust from the road surface, or that derived from entrainment of polluted roadside soils, either directly or as a component of road surface dust. 相似文献
4.
Shao L Shi Z Jones TP Li J Whittaker AG Bérubé KA 《The Science of the total environment》2006,367(1):261-272
An in vitro plasmid assay was employed to study the bioreactivity of PM (particulate matter) in Beijing air. It was found that the TD20 (toxic dose of PM causing 20% of plasmid DNA damage) of Beijing PM can be as low as 28 microg ml(-1) and as high as >1000 microg ml(-1). Comparison of the physical properties, such as morphology and size distribution, and oxidative potential indicates that the PM(2.5) (particulate matter with an aerodynamic diameter of 2.5 microm or less) has a stronger oxidative capacity than PM(10) (particulate matter with an aerodynamic diameter of 10 microm or less), and that the higher number percentages of soot aggregates and lower number percentages of mineral and fly ashes are associated with the higher oxidative capacity. Although the mass of PM(10) during dust storms is commonly 5 times higher than that during non-dust storm episodes, the oxidative capacity of PM(10)s of dust storms is much lower than that of the non-dust storm PM(10)s. The water-soluble fractions and intact whole particle solutions of Beijing airborne particles produce similar plasmid assay results, demonstrating that the bioreactivity of Beijing airborne particles is mainly sourced from the water-soluble fraction. In the samples with stronger bioreactivity, the total analyzed water soluble Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As and Pb (ppm) concentrations are higher. The water soluble zinc shows a good negative correlation with TD20s, suggesting that the water-soluble zinc is probably the major element responsible for the plasmid DNA damage. 相似文献
5.
Christos Halios Mat Santamouris Maria Kapsalaki Dimitris Tsakos 《The Science of the total environment》2009,407(17):4894-4901
The aim of the present work is to study the occupants' exposure to fine particulate concentrations in ten nightclubs (NCs) in Athens, Greece. Measurements of PM1 and PM2.5 were made in the outdoor and indoor environment of each NC. The average indoor PM1 and PM2.5 concentrations were found to be 181.77 μg m− 3 and 454.08 μg m− 3 respectively, while the corresponding outdoor values were 11.04 μg m− 3 and 32.19 μg m− 3. Ventilation and resuspension rates were estimated through consecutive numerical experiments with an indoor air quality model and were found to be remarkably lower than the minimum values recommended by national standards. The relative effects of the ventilation and smoking on the occupants' exposures were examined using multiple regression techniques. It was found that given the low ventilation rates, the effect of smoking as well as the occupancy is of the highest importance. Numerical evaluations showed that if the ventilation rates were at the minimum values set by national standards, then the indoor exposures would be reduced at the 70% of the present exposure values. 相似文献
6.
Wind tunnel experiments and Computational Fluid Dynamics (CFD) are used to analyse the flow conditions in a venturi-shaped roof, with focus on the underpressure in the narrowest roof section (contraction). This underpressure can be used to partly or completely drive the natural ventilation of the building zones. The wind tunnel experiments are performed in an atmospheric boundary layer wind tunnel at scale 1:100. The 3D CFD simulations are performed with steady RANS and the RNG k-? model. The purpose of this study is twofold: (1) to evaluate the accuracy of steady RANS and the RNG k-? model for this application and (2) to assess the magnitude of the underpressures generated with different design configurations of the venturi-shaped roof. The CFD simulations of mean wind speed and surface pressures inside the roof are generally in good agreement (10–20%) with the wind tunnel measurements. The study shows that for the configuration without guiding vanes, large negative pressure coefficients are obtained, down to −1.35, with reference to the free-stream wind speed at roof height. The comparison of design configurations with and without guiding vanes shows an – at least at first sight – counter-intuitive result: adding guiding vanes strongly decreases the absolute value of the underpressure. The reason is that the presence of the guiding vanes increases the flow resistance inside the roof and causes more wind to flow over and around the roof, and less wind through it (wind-blocking). As a result, the optimum configuration is the one without guiding vanes. 相似文献
7.
This comprehensive study, a first in Flanders, Belgium, aimed at characterizing the residential indoor air quality of subgroups that took part in the European Community Respiratory Health Survey (ECRHS I—1991 and ECHRS II—1996) questionnaire-based asthma and related illnesses studies. This pilot study aimed at the evaluation of particulate matter and various inorganic gaseous compounds in residences in Antwerp. In addition personal exposure to the gaseous compounds of one individual per residence was assessed. The main objective was to obtain some base-line pollutant levels and compare these with studies performed in other cities, to estimate the indoor air quality in residences in Antwerp. Correlations between the various pollutant levels, indoor:outdoor ratios and the micro-environments of each residence were investigated. This paper presents results on indoor and ambient PM1, PM2.5 and PM10 mass concentrations, its elemental composition in terms of K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Pb, Al, Si, S and Cl and the water-soluble ionic concentrations in terms of SO42−, NO32−, Cl−, NH4+ K+, Ca2+. In addition, indoor, ambient and personal exposure levels of the gases NO2, SO2, and O3 were determined. Elevated indoor:outdoor ratios were found for NO2 in residences containing gas stoves. In smoker's houses increased PM concentrations of 58 and 43% were found for the fine and coarse fractions respectively. Contrary to the fact that all I/O ratios of the registered elements in each individual house were significantly correlated to each other, no correlation could be established between the I/O ratios of the different houses, thus indicating a unique micro-environment for each residence. Linear relationships between the particulate matter elemental composition, SO2 and O3 levels indoors and outdoors could be established. No linear relationships between indoor and outdoor NO2 and particulate mass concentrations were found. 相似文献
8.
The influence of natural ventilation on heating load and energy savings in a building with a double skinned envelope (DSE) was examined in this study. Field measurements and computer simulations were performed under various weather conditions. The DSE was effective for saving energy and creating natural ventilation rates under clear and partly cloudy skies. Due to insufficient irradiance, the DSE was not effective for reducing the heating load under overcast sky conditions. When natural airflow rates from the cavity space between internal and external skin to the indoor space were controlled, the southwest-facing DSE effectively reduced heating loads due to the accumulation of solar irradiance.Regression models showed that outdoor air temperature was the most significant factor governing variations in cavity temperature under all sky conditions. Computer simulations indicated that natural ventilation was practical at an appropriate supply temperature only when the sky ratio was less than 0.7. The airspace in cavity of the DSE provided additional natural ventilation rates to the indoor space and effectively reduced heating loads. Natural ventilation was available for 135 h during three winter months without consuming additional energy to heat the outdoor air. The heating load was reduced by the DSE ranged from 17.98% to 18.7% depending on the airflow control options for the cavity space. 相似文献
9.
M. Samer C. LoebsinM. Fiedler C. AmmonW. Berg P. SanftlebenR. Brunsch 《Energy and Buildings》2011,43(12):3718-3728
Experiments were performed to study the airflow rates (AFRs) in a naturally ventilated building through four summer seasons and three winter seasons. The AFRs were determined using heat balance (HB), tracer gas technique (TGT) and CO2-balance as averages of the values of all experiments carried out through the different seasons. The statistical analyses were correlation analysis, regression model and t-test. Continuous measurements of gaseous concentrations (NH3, CH4, CO2 and N2O) and temperatures inside and outside the building were performed. The HB showed slightly acceptable results through summer seasons and unsatisfactory results through winter seasons. The CO2-balance showed unexpected high differences to the other methods in some cases. The TGT showed reliable results compared to HB and CO2-balance. The AFRs, subject to TGT, were 0.12 m3 s−1 m−2, 1.15 m3 s−1 cow−1, 0.88 m3 s−1 LU−1, 56 h−1, 395 m3 s−1 and 470 kg s−1 through summer seasons, and 0.08 m3 s−1 m−2, 0.83 m3 s−1 cow−1, 0.64 m3 s−1 LU−1 39 h−1, 275 m3 s−1 and 328 kg s−1 through winter seasons. The AFRs are not independent values, rather they were estimated for specific reference values, which are: area, cow and LU as well as rates. The emission rates through summer seasons, subject to TGT, were 9.4, 40, 3538 and 2.3 g h−1 cow−1; and through winter seasons were 4.8, 19, 2332 and 2.6 g h−1 cow−1, for NH3, CH4, CO2 and N2O, respectively. 相似文献
10.
11.
Hanna Boogaard Denise R. Montagne Alexander P. Brandenburg Kees Meliefste Gerard Hoek 《The Science of the total environment》2010,408(20):4403-4411
Recent interest has focused on the health effects of ultrafine particles because of the documented toxicity and the larger concentration contrast near motorways of UFP than for PM10 or PM2.5. There are only few studies that have measured UFP at inner-city streets simultaneously with other PM components.The aim of this study was to compare the contrast of UFP, PM10 and soot measured simultaneously at 3 inner-city locations, namely a moderately busy street (15,000 vehicles/day), a city and a suburban background location.Simultaneously, measurements of particle number concentrations (PNC), PM10 and soot have been conducted on three locations in and around Utrecht, a medium-sized city in the Netherlands for 20 weekdays in autumn 2008. Measurements were done for 6-h during afternoon and early evening.The mean PNC at the street location was more than 3 times higher than at the two background locations. The contrast was similar for soot concentrations. In PM10 concentrations less contrast was found, namely 1.8 times. Mean PNC concentrations were poorly correlated with PM10 and soot. At the street location, high temporal variation of PNC concentrations occurred within each sampling day, probably related to variations in traffic volumes, high-emission individual vehicles and wind direction. Temporal variation was smaller at the two background locations. Occasional unexplained short-term peaks occurred at the suburban background location. A relatively high correlation between PNC minute values at the two background locations was found, pointing to similar area-wide sources. Typically low correlations were found with the street locations, consistent with the dominant impact of local traffic.A large contrast between two background locations and a moderately busy urban street location was found for PNC and soot, comparable to previous studies of much busier motorways. Temporal variation of PNC was higher at the street location and uncorrelated with background variations. 相似文献
12.
Short-term effect of fine particulate matter (PM2.5) on daily mortality due to diseases of the circulatory system in Madrid (Spain) 总被引:2,自引:0,他引:2
Introduction
Owing to their small size, fine particles, i.e., those having a diameter ≤ 2.5 μm (PM2.5), have a high alveolar penetration capacity, thereby triggering a local inflammatory process with circulatory repercussion. Despite being linked to respiratory and cardiovascular morbidities, there is limited evidence of an association between this type of particulate matter and short-term increases in mortality.Objective
The aim of this study was to analyse and quantify the short-term impact of PM2.5 on daily mortality due to diseases of the circulatory system, registered in Madrid from 1 January 2003 to 31 December 2005.Methods
An ecological longitudinal time-series study was conducted, with risks being quantified by means of Poisson regression models. As a dependent variable, we took daily mortality registered in Madrid from 1 January 2003 to 31 December 2005, attributed to all diseases of the circulatory system as classified under heads I00-I99 of the International Classification of Diseases-10th revision (ICD-10) and broken down as follows: I21, acute myocardial infarction (AMI); I20, I22-I25, other ischemic heart diseases; and I60-I69, cerebrovascular diseases. The independent variable was daily mean PM2.5 concentration. The other variables controlled for were: chemical pollution (PM10, O3, SO2, NO2 and NOx); acoustic and biotic pollution; influenza; minimum and maximum temperatures; seasonalities; trend; and autocorrelation of the series.Results
A linear relationship was observed between PM2.5 levels and mortality due to diseases of the circulatory system. For every increase of 10 μg/m3 in daily mean PM2.5 concentration, the relative risks (RR) were as follows: for overall circulatory mortality, associations were established at lags 2 and 6, with RR of 1.022 (1.005-1.039) and 1.025 (1.007-1.043) respectively; and for AMI mortality, there was an association at lag 6, with an RR of 1.066 (1.032-1.100). The corresponding attributable risks percent (AR%) were 2.16%, 2.47% and 6.21% respectively. No statistically significant association was found with other ischemic heart diseases or with cerebrovascular diseases.Conclusion
PM2.5 concentrations are an important risk factor for daily circulatory-cause mortality in Madrid. From a public health point of view, the planning and implementation of specific measures targeted at reducing these levels constitute a pressing need. 相似文献13.
Investigating the potential role of ammonia in ion chemistry of fine particulate matter formation for an urban environment 总被引:3,自引:0,他引:3
To investigate the potential role of ammonia in ion chemistry of PM2.5 aerosol, measurements of PM2.5 (particulate matter having aerodynamic diameter < 2.5 µm) along with its ionic speciation and gaseous pollutants (sulfur dioxide (SO2), nitrogen oxides (NOx), ammonia (NH3) and nitric acid (HNO3)) were undertaken in two seasons (summer and winter) of 2007-2008 at four sampling sites in Kanpur, an urban-industrial city in the Ganga basin, India. Mean concentrations of water-soluble ions were observed in the following order (i) summer: SO42− (26.3 µg m− 3) > NO3− (16.8) > NH4+ (15.1) > Ca2+ (4.1) > Na+ (2.4) > K+ (2.1 µg m− 3) and (ii) winter: SO42− (28.9 µg m− 3) > NO3− (23.0) > NH4+ (16.4) > Ca2+(3.4) > K+(3.3) > Na+ (3.2 µg m− 3). The mean molar ratio of NH4+ to SO42− was 2.8 ± 0.6 (mostly >2), indicated abundance of NH3 to neutralize H2SO4. The excess of NH4+ was inferred to be associated with NO3− and Cl−. Higher sulfur conversion ratio (Fs: 58%) than nitrogen conversion ratio (Fn: 39%) indicated that SO42− was the preferred secondary species to NO3−. The charge balance for the ion chemistry of PM2.5 revealed that compounds formed from ammonia as precursor are (NH4)2SO4, NH4NO3 and NH4Cl. This study conclusively established that while there are higher contributions of NH4+, SO42− to PM2.5 in summer but for nitrates (in particulate phase), it is the winter season, which is critical because of low temperatures that drives the reaction between ammonia and HNO3 in forward direction for enhanced nitrate formation. In summary, inorganic secondary aerosol formation accounted for 30% mass of PM2.5 and any particulate control strategy should include optimal control of primary precursor gases including ammonia. 相似文献
14.
The inorganic main elements, trace elements and PAHs were determined from selected PM1, PM2.5 and PM10 samples collected at the Nordic background station in Virolahti during different seasons and during the wildfire episodes in 2006. Submicron particles are those most harmful to human beings, as they are able to penetrate deep into the human respiratory system and may cause severe health effects. About 70-80%, of the toxic trace elements, like lead, cadmium, arsenic and nickel, as well as PAH compounds, were found in particles smaller than 1 µm. Furthermore, the main part of the copper, zinc, and vanadium was associated with submicron particles. In practice, all the PAHs found in PM10 were actually in PM2.5. For PAHs and trace elements, it is more beneficial to analyse the PM2.5 or even the PM1 fraction instead of PM10, because exclusion of the large particles reduces the need for sample cleaning to minimize the matrix effects during the analysis. During the wildfire episodes, the concentrations of particles smaller than 2.5 µm, as well as those of submicron particles, increased, and also the ratio PM1/PM10 increased to about 50%. On the fire days, the mean potassium concentration was higher in all particle fractions, but ammonium and nitrate concentrations rose only in particles smaller than 1.0 µm. PAH concentrations rose even to the same level as in winter. 相似文献
15.
The coupling of thermal mass and natural ventilation is important to passive building design. Thermal mass can be classified as external thermal mass and internal thermal mass. Due to great diurnal variation of ambient air temperature and solar radiation intensity, heat transfer through building envelopes, which is called external thermal mass, is a complex and unsteady process. Indoor furniture are internal thermal mass, affecting the indoor air temperature through the process of absorbing and releasing heat. In this paper, a heat balance model coupling the external and internal thermal mass, natural ventilation rate and indoor air temperature for naturally ventilated building is developed. In this model, the inner surface temperature of building envelopes is obtained based on the harmonic response method. The effect of external and internal thermal mass on indoor air temperature for six external walls is discussed of different configurations including lightweight and heavy structures with and without external/internal insulation. Based on this model, a simple tool is developed to estimate the indoor air temperature for certain external and internal thermal mass and to determine the internal thermal mass needed to maintain required indoor air temperature for certain external wall for naturally ventilated building. 相似文献
16.
Ma Y Chen R Pan G Xu X Song W Chen B Kan H 《The Science of the total environment》2011,409(13):2473-2477
Fine particulate matter (PM2.5) is not a criteria pollutant in China, and few studies were conducted in the country to investigate the health impact of PM2.5. In this study, we did a time-stratified case-crossover analysis to examine the association between PM2.5 and daily mortality in Shenyang, an industrial center in northeast China. Daily mortality, air pollution and weather data from August 1, 2006 to December 31, 2008 in Shenyang were collected. A time-stratified case-crossover approach was used to estimate the association of PM2.5 with both total and cause-specific mortality. Controls were selected as matched days of the week in the same month. Potential effect modifiers, such as age, gender, and season, were also examined. We found significant associations between PM2.5 and daily mortality in Shenyang. A 10 μg/m3 increment in the 2-day moving average (lag 01) concentrations of PM2.5 corresponded to 0.49% (95% CI: 0.19%, 0.79%), 0.53% (95% CI: 0.09%, 0.97%), and 0.97% (95% CI: 0.01%, 1.94%) increase of total, cardiovascular, and respiratory mortality, respectively. The associations appeared to be stronger in older people (aged ≥ 75 years), in females and during the warm season. To our knowledge, this is the longest PM2.5 health study in time duration in China. Our findings provide new information on the adverse health effects of PM2.5, and may have implications for environmental policy making and standard setting in China. 相似文献
17.
Temporal variation of nitro-polycyclic aromatic hydrocarbons in PM10 and PM2.5 collected in Northern Mexico City 总被引:1,自引:0,他引:1
B.L. Valle-Hernández V. Mugica-Álvarez E. Salinas-Talavera M.A. Murillo-Tovar R. Villalobos-Pietrini 《The Science of the total environment》2010,408(22):5429-59
With the aim to determine the presence of individual nitro-PAH contained in particles in the atmosphere of Mexico City, a monitoring campaign for particulate matter (PM10 and PM2.5) was carried out in Northern Mexico City, from April 2006 to February 2007. The PM10 annual median concentration was 65.2 μg m− 3 associated to 7.6 μg m− 3 of solvent-extractable organic matter (SEOM) corresponding to 11.4% of the PM10 concentration and 38.6 μg m− 3 with 5.9 μg m− 3 SEOM corresponding to 15.2% for PM2.5. PM concentration and SEOM varied with the season and the particle size. The quantification of nitro-polycyclic aromatic hydrocarbons (nitro-PAH) was developed through the standards addition method under two schemes: reference standard with and without matrix, the former giving the best results. The recovery percentages varied with the extraction method within the 52 to 97% range depending on each nitro-PAH. The determination of the latter was effected with and without sample purification, also termed fractioning, giving similar results. 8 nitro-PAH were quantified, and their sum ranged from 111 to 819 pg m− 3 for PM10 and from 58 to 383 pg m− 3 for PM2.5, depending on the season. The greatest concentration was for 9-Nitroanthracene in PM10 and PM2.5, detected during the cold-dry season, with a median (10th-90th percentiles) concentration in 235 pg m− 3 (66-449 pg m− 3) for PM10 and 73 pg m− 3 (18-117 pg m− 3) for PM2.5. The correlation among mass concentrations of the nitro-PAH and criteria pollutants was statistically significant for some nitro-PAH with PM10, SEOM in PM10, SEOM in PM2.5, NOX, NO2 and CO, suggesting either sources, primary or secondary origin. The measured concentrations of nitro-PAH were higher than those reported in other countries, but lower than those from Chinese cities. Knowledge of nitro-PAH atmospheric concentrations can aid during the surveillance of diseases (cardiovascular and cancer risk) associated with these exposures. 相似文献
18.
In earlier work [1], NIST developed a climate suitability analysis method to evaluate the potential of a given location for direct ventilative cooling and nighttime ventilative cooling. The direct ventilative cooling may be provided by either a natural ventilation system or a fan-powered economizer system. The climate suitability analysis is based on a general single-zone thermal model of a building configured to make optimal use of direct and/or nighttime ventilative cooling. This paper describes a new tool implementing this climate suitability methodology and its capability to consider an adaptive thermal comfort option and presents results from its application to analyze a variety of U.S. climates. The adaptive thermal comfort option has the potential to substantially increase the effectiveness of natural ventilation cooling for many U.S. cities. However, this impact is very dependent on the acceptable humidity range. If a dewpoint limit is used, the increase is significant for a dry climate such as Phoenix but much smaller for humid climates such as Miami. While ASHRAE Standard 55 does not impose a limit on humidity when using the adaptive thermal comfort option, the necessity of limiting humidity for other reasons needs to be considered. 相似文献
19.
对四栋不同朝向、不同体型、不同空调系统形式的办公建筑进行了无组织通风测试,从典型房间和建筑物整体分析了开窗、开门和通风系统设计不当产生的无组织通风量的大小及其对空调能耗的影响。 相似文献
20.
Atmospheric particulate matter (PM) fractions (PM(10) and PM(2.5)) were sampled concurrently between June 2004 and May 2005 at two sites (urban and suburban) in Izmir, Turkey. The elemental composition of PM (Al, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, V, and Zn) was determined using inductively coupled plasma-optical emission spectrometer. Elemental compositions of several PM sources were also characterized. Positive matrix factorization (PMF) and chemical mass balance modeling (CMB) were applied to determine the PM sources and their contributions to air concentrations. The major contributors to PM were fossil fuel burning, traffic emissions, mineral industries and marine salt according to the PMF results. However, undetermined parts were more than 40%. On the other hand, the contributions to PM could be determined completely by CMB, and the dominant contributor was traffic with >70% at the two sites. Fossil fuel burning, mineral industries, marine salt and natural gas-fired power plant were the minor contributors. 相似文献