Indoor and Built Environment recent issues

Low Carbon Urban Built Environments (LCUBE)

Fri, 23 Oct 2009 04:11:42 PDT

A Low Carbon Built Environment

Jones, P. — Fri, 23 Oct 2009 04:11:42 PDT

Residential Location, Travel Behaviour, and Energy Use: Hangzhou Metropolitan Area Compared to Copenhagen

Naess, P. — Fri, 23 Oct 2009 04:11:42 PDT

This paper presents the results of a study of the influence of residential locations on travelling behaviour in the Hangzhou Metropolitan Area in China. Based on a combination of quantitative and qualitative research methods, the study shows that the location of a dwelling, relative to the centre structure of Hangzhou Metropolitan Area, can exert a considerable influence on the travelling behaviour of the respondents included in the survey. On average, people living close to downtown Hangzhou used less energy for transport. They travelled less in total and made a greater share of their journeys by bike or on foot.

The location of the dwelling relative to the closest second-order and third-order centre can also influence travelling, but not to the same extent as the location of the residence relative to the city centre of Hangzhou. The geographical differences in travelling behaviour exist independently of residential preferences and attitudes to transport and environmental issues and therefore cannot be explained by residential self-selection. Instead, a number of rationales for travel behaviour identified in the qualitative interviews showed important links in the causal mechanisms by which residential location can influence travel.

Exergy Analysis in Low Carbon Technologies -- The Case of Renewable Energy in the Building Sector

Xydis, G. — Fri, 23 Oct 2009 04:11:42 PDT

In this paper, the availability of different Low Carbon Technologies (LCT) is examined using the method of Exergy Analysis. LCT utilization plays a significant role in the Urban Environment. In many areas, as in construction industry, in fuels and ‘‘conventional’’ energy production, in renewable energy sources (RES), and in transportation there is a focus on technologies that offer the greatest carbon-saving potential. RES offer different LCT as biomass-local electricity and heat generation, geothermal, hydro energy, solar photovoltaic, solar thermal electric (high-temperature generation), solar water-heating collectors, tidal energy, wave energy, and wind power. Continuously increased energy consumption over the last decades in all sectors indicates that a wider LCT utilization is needed. An initial analysis is presented and an availability analysis is been implemented in order to identify whether there is room for more improvement based on the plan for a cost-effective contribution to carbon saving in short and longer term. The ultimate aim of the present study is to analyze the exergy utilization of LCT in order to gain insights of their efficiency

Combining Stationary and Mobile Energy Requirements: The Importance of the Meso-level in Sustainable Urban Development

Hoyer, K. G. — Fri, 23 Oct 2009 04:11:42 PDT

This paper addresses the superior issue of systems for the achievement of very low carbon and very low energy urban buildings. In many larger European cities contemporary major urban renewal is carried out through development of large building and housing complexes, either as separate renewal projects or as parts of more extensive urban renewal programs. This is taking place in what we may term a meso-level in urban development. Besides the importance in current large city development, the focus on large urban building and housing complexes may play crucial functions in the broader context of urban sustainability. These building complexes are major nodes for the generation of many forms of stationary as well as mobile (transport) energy use, giving a context for the development of innovative systems both for increased energy efficiency and utilization of alternative energy sources. As large energy use nodes in the urban structures, the building and housing complexes give particularly favorable conditions for development of common renewable energy systems for stationary purposes; however, also conditions favorable to the implementation of systems to substantially reduce energy use and increase alternative energies in various forms of transportation.

Environmental Comparison of the Use of Biodiesel and Gasoline for Transportation -- A Case Study for Athens

Nanaki, E. A. — Fri, 23 Oct 2009 04:11:42 PDT

Energy usage, in the Greek transport sector, takes the form of gasoline consumption by automobiles, diesel oil for taxis, trucks, maritime transport, and railroads as well as jet fuel for aircraft. The control of CO₂ emissions constitutes a major environmental issue in most countries and many authorities seek to stabilize or decrease these emissions. During the past decade, biofuels in the form of blended gasoline and biodiesel have begun to find places in the energy economy since a sustainable transport future requires the reduction of CO₂ emissions. The Greek car market shows a remarkably low rate in the penetration of biodiesel compared to the average European Union market. In this study we try to find out the combined effects of probable changes in biodiesel and gasoline future fuel consumption in the city of Athens.

Improving Thermal Insulation of Concrete Sandwich Buildings

Munch-Andersen, J. — Fri, 23 Oct 2009 04:11:42 PDT

Increased requirement for the thermal insulation of buildings and reduction of energy consumption in order to decrease their carbon dioxide emission means that buildings only 30 years old are of a very low standard compared to today’s requirements. Therefore, there is a strong need to improve the insulation of many existing buildings. Improving insulation can be a risky business as experience has shown that different sorts of degradation will often occur after such work. On the other hand, improvement of the insulation could contribute to making a building more attractive to tenants.

This article deals with good technical solutions for improving the insulation of concrete sandwich panel buildings from the 1960s and 1970s as well as how the savings in supplied energy can be estimated in a simple and accurate manner.

New Strategies for the Reduction of Shopping Centers Generated Car Trips -- Theory and Experiences

Husler, W., Urbani, L. — Fri, 23 Oct 2009 04:11:42 PDT

The relation between urban life and commerce has always been ambivalent. Technical norms and guidelines of the 1970s and 1980s provided an indication of the minimum number of parking places that need to be provided in connection with the construction of a new commercial center. Later on it became clear that it was not sufficient just to provide cars with a place to park, it was also necessary to provide them with adequate facilities to arrive and to leave. In recent years interesting programs to try and resolve the problems have been started in the city of Zurich. The innovative ‘‘trip model’’ moves the focus to the factors that are directly responsible for the disturbing emissions and binds building licenses to a certain number of emission generating car trips per year rather than to a determined number of parking lots.

Patterns and Implications of User Control Actions in Buildings

Mahdavi, A. — Fri, 23 Oct 2009 04:11:42 PDT

The control actions by the inhabitants of buildings can significantly affect the energy performance of buildings and their environmental impact. However, relatively few studies have investigated such actions in detail and on a long-term basis. In most buildings, occupants operate control devices such as windows, shades, luminaries, radiators, and fans to bring about desirable indoor environmental conditions. Knowledge of such user actions is crucial for accurate prediction of building performance (energy use, indoor climate) and effective operation of building service systems. The present contribution describes an effort to observe control-oriented occupant behavior in office buildings in Austria over a period of 1 year. Thereby, user control actions as related to one or more of the building systems for ambient lighting, shading, window ventilation, and heating were monitored together with indoor and outdoor environmental parameters. The collected data has been analyzed to explore relationships between the kinds and frequency of the control actions and the magnitude and dynamism of indoor and outdoor environmental changes. Moreover, implications of user actions for energy use are studied.

Elements and Strategies for Sustainable Intervention in the Residential Building Sector: a Case Study

Albatici, R. — Fri, 23 Oct 2009 04:11:42 PDT

This paper deals with research carried out at the Laboratory of Building Design, University of Trento, Italy to define possible design actions to improve energy efficiency and indoor comfort conditions in residential buildings. The paper presents retrofitting interventions both in wintertime and summertime, through the use of passive solar elements and of natural materials typical of the local building tradition. There were five stages of research: (1) critical analysis and classification of sustainable buildings in the Italian Alpine region; (2) recording data of the temporal courses of specific indoor environmental parameters in some rooms of selected existing buildings during real life conditions; (3) setting up of a virtual model of the buildings in dynamic state conditions; (4) a critical calibration of the model in order to take into account the real behaviour of the inhabitants and their use of the building components; (5) modification of some features on the model (materials, shape and so on) in order to achieve better performances concerning users’ comfort conditions and energy saving issues. In consequence, it is now possible to evaluate the real effectiveness of bioclimatic design procedures and to propose guidelines concerning the design of sustainable wooden buildings. Finally, some specific recommendations are given based on the critical analysis of the simulation results.

ZEITMOP Concept -- A Polygeneration System for Municipal Energy Demands

Gorski, J., Yantovski, E. — Fri, 23 Oct 2009 04:11:42 PDT

The reduction of greenhouse gases (to which CO₂ contributes over 60%) to stop global warming is now a major priority for governments around the world. One approach, described in this paper, concerns the ‘‘clean energy’’ or ‘‘zero-emission’’ technologies. An original concept of a semi-closed zero emission ion transport membrane oxygen power (ZEITMOP) cycle is being developed. It can be compared to other research initiatives such as clean energy systems and zero-emission natural gas, as a response to the well-recognised challenges. As an answer to the crucial question of reduction of greenhouse gas emissions we propose new zero-emission fuel-fired power plants and boiler houses (‘‘ZEITMOP Boiler & Air Cooler’’ and ‘‘Zero Emission Membrane Smokeless Heating’’). Zero-emission co-generation of power and heat allows such plants to be located in densely populated areas close to the consumer.

The Energy and Cost Implications of the Renewable Energy Scheme at the Integrated Home for Older People, Plas y Mor, Llanelli, Wales

Roberts, P. — Fri, 23 Oct 2009 04:11:43 PDT

Plas y Môr is a ground-breaking project in the social housing sector in Wales. Completed in 2003, it provides 38 flats as well as care and a wide range of other facilities for the elderly. The building combines a number of renewable energy technologies within a highly insulated timber-frame, including passive and active solar technologies and biomass wood pellet fuelled boilers servicing a communal heating scheme. This paper briefly describes how the building works, and examines its performance to date. It compares predicted energy use against actual data from available utility bills over the period of operation of the scheme. Comparison with similarly sized, residential scheme show that Plas y Môr is performing well, despite a few initial setbacks.

A Change of Editor -- Happy Retirement John

Lange, J.H., Yu, C., Yik, F. W.H. — Mon, 10 Aug 2009 07:16:42 PDT

Measuring and Analyzing Frequency Responses of Heat Conduction in Nanjing Buildings under In Situ Conditions

Changhai Peng, , Zhishen Wu, — Mon, 10 Aug 2009 07:16:42 PDT

In this paper we present in-situ measurements of the thermal characteristics of buildings in Nanjing, including information about the test chamber and arrangement of measuring points as well as measurement results, taken in Nanjing during the summer of 2001. A method for the analysis of in situ data is also presented that involves calculating frequency responses of heat conduction in buildings under in situ conditions. The main conclusions are as follows: For the zeroth and the first-order response of the frequency responses of heat conduction in buildings, the measured values match very well with theoretical values; therefore, it is possible to apply this analytical method in practical situations. However, the values measured were lower than the theoretical values, primarily, it was thought, because the tested buildings might not be dry enough; they might be affected by thermal bridges, and/or the un-controlled climate could affect measurements under field conditions. For the second-order response, the difference between the test values and theoretical values was too large to be accepted. Therefore, it was concluded that it was too difficult to measure accurately the second-order response of the frequency responses of heat conduction in buildings under in situ conditions. However, for the decay rate of the first-order response, values have already reached 20 times those needed to meet the requirements of engineering plans. We conclude, it is advisable to calculate the frequency responses of heat conduction in buildings under in situ conditions using the first-order response.

Indoor Environmental Quality Related to Occupant Satisfaction and Performance in LEED-certified Buildings

Lee, Y. S., Guerin, D. A. — Mon, 10 Aug 2009 07:16:42 PDT

The purpose of this study was to identify whether the indoor environmental quality design criteria: office layout, office furnishing, thermal comfort, indoor air quality, lighting, acoustics, and cleanliness and maintenance in relation to the overall workspace for LEED^®-acreditation, could significantly affect occupants’ perception of their overall workspace satisfaction and their work performances. Occupants’ self-assessed satisfaction and performances were measured and these were correlated with occupants’ satisfaction and performances in their overall workspaces in 15 LEED-certified buildings in the US. The findings showed office furnishing quality has a significant impact on occupants’ satisfaction and performances; and indoor air quality affected only the occupants’ performances

Measurement of Airflow around the Human Body with Wide-cover Type Personal Air-conditioning with PIV

Jeong-Hoon Yang, , Shinsuke Kato, , Ho-Tae Seok, — Mon, 10 Aug 2009 07:16:42 PDT

Many existing personal air-conditioning systems cool only specific portions of the human body in the form of spot cooling, using either cooled or fast airflow to control thermal sensation. This may cause various problems related to localized airflow, such as discomfort to the face and neck areas and dryness in the eyes. Therefore, a method is proposed in this research for task area wide-cover type personal air-conditioning that prevents the task area of a human body from being exposed to a largely irregular thermal environment. A particle image velocimeter was used in the research to measure airflow fields for conventional spot cooling and wide-cover type personal air-conditioning (PAC) around the human body. The spot cooling type PAC formed an airflow of 0.3—0.6 m/s around the area of the neck. However, the wide-cover type PAC formed a calmer airflow field of less than 0.18 m · s^-1 around the human body. This is because the supply air from a wide-cover type PAC has a higher density than the surrounding air and can extensively cover the human body. Therefore, the wide-cover type PAC can minimize the potential for cold drafts to affect the human body.

An Experimental Investigation of the Carbonation of Blended Portland Cement Palm Oil Fuel Ash Mortar in an Indoor Environment

Rukzon, S., Chindaprasirt, P. — Mon, 10 Aug 2009 07:16:42 PDT

In this research, palm oil fuel ash was utilized as a pozzolanic material in blended Portland cement mortar. The mortar was tested on the normal compressive strength and the negative effect of carbonation in indoor environment using the accelerated carbonation test of 5% CO₂ in 50% relative humidity. Three palm oil fuel ash fractions of different fineness, viz., coarse original palm oil fuel ash (CPOA), medium palm oil fuel ash (MPOA) and fine palm oil fuel ash (FPOA) were used for the study. Ordinary Portland cement (OPC) was partially replaced by these palm oil fuel ashes at the dosages of 20% and 40% by weight of binder. The results showed that the incorporation of the ashes affected the strength and the carbonation depths of mortars. The strengths of mortar slightly decreased with the increases in the dosage of the ash. The fineness of ash, on the other hand, improved the strength and the carbonation of the mortars. The mortars containing FPOA exhibited high strength and relatively low carbonation in comparison to those using coarser MPOA and CPOA. The use of FPOA resulted in a strong and dense mortar owing to the increased packing effect and pozzolanic reaction. It was therefore, demonstrated that the FPOA could be used as a pozzolanic material to replace part of Portland cement for use in the indoor environment.

Daylight Ratio, Luminance, and Visual Comfort Assessments in Typical Malaysian Hostels

Dahlan, N.D., Jones, P.J., Alexander, D.K., Salleh, E., Alias, J. — Mon, 10 Aug 2009 07:16:42 PDT

Conventional tropical building designs are experiencing a new paradigm in their environmental response to improve lighting ambiance and occupants’ visual comfort through the exploitation of daylighting. However, it is important for architects to understand that flaws in daylighting strategies could lead to disadvantages as they could hinder vision, cause discomfort, increase interior heat gain, and result in excessive energy demands. The objective of this study was to assess how occupants’ perceived their visual conditions through daylight ratio and luminance level measurements. Measurements were conducted throughout a 2-month period starting from 12th May to 3rd July 2007. Three case studies were conducted at typical Malaysian hostels located in the Klang Valley. Those selected were: the Twelfth Residential College, Universiti Malaya (H1); the Eleventh Residential College, Universiti Putra Malaysia (H2); and Murni Student Apartments, Universiti Tenaga Nasional (H3). The daylighting source in all these case studies were from side-lit windows. Overall, the findings suggested that occupants were at ease with the level of daylighting available in their rooms even though rooms that were shaded by projecting balconies (i.e.,: H1) were dimmer than the rooms that were not shaded (i.e.,: H2 and H3).

A Field Survey of the Expected Desirable Thermal Environment for Older People

Wong, L.T., Fong, K.N.K., Mui, K.W., Wong, W.W.Y., Lee, L.W. — Mon, 10 Aug 2009 07:16:42 PDT

In order to identify an indoor thermally comfortable environment for older people, this study examined the thermal acceptance of 384 older people of ages from 60 to 97 years under various thermal environmental conditions in 19 centers for older people in Hong Kong. The results were compared to those of the younger residents in Hong Kong. A probable decay of one predicted mean vote (PMV) for every 25.3 years was reported for older people beyond the age of 60 years ( p ≤ 0.05), which indicated that the older age group probably has a different expectation of a thermoneutral environment as compared with younger age groups. It was also noted that the expected PMV for a thermoneutral environment of older females was apparently higher than that for older males in the same age group. The results should be a useful reference for an acceptable thermally comfortable environment in centers for older people up to the age group over 90 years.

The Influence of Ventilation Design Mixes on the Thermal Environment in Elementary School Classrooms

Chiang, C.-m., Lai, C.-m. — Mon, 10 Aug 2009 07:16:42 PDT

The roofs of most of the buildings in Taiwan are exposed to direct (overhead) solar radiation during the summer season because it is located near the Tropic of Cancer. The estimated yearly solar heat gain received from a roof is 2.78 times greater than that gained from a south-side wall (the second highest in terms of solar heat gain). Since most elementary schools in Taiwan are not equipped with air conditioners, the classrooms, especially those located on the upper floors, are regularly overheated. Solving the problem of ventilation and improving the thermal environment in Taiwan elementary school classrooms is an important endeavor. CFD simulations were conducted to investigate six combinations of designs that can incorporate natural ventilation (double roofs, ‘‘Covered Ridge with Sidewall Opening’’ (CRSOs), roof ridge openings, and window layout) influence indoor thermal environments, especially during the summer season when the outdoor wind velocity is low. The results show that when a double roof, roof ridge openings, and a CRSO are implemented, both the ventilation performance and the thermal environment of the classrooms are improved, regardless of whether the windows are laid out in a staggered formation (high-low) or in a conventional window layout.

Numerical Investigation of Indoor Aerosol Particle Dispersion under Stratum Ventilation and under Displacement Ventilation

Lin Tian, , Zhang Lin, , Qiuwang Wang, , Jing Liu, — Mon, 10 Aug 2009 07:16:42 PDT

Particle dispersion in a room under stratum ventilation and under displacement ventilation have been investigated by numerical simulation. In addition, an experiment was carried out involving the newer stratum ventilation. The agreements between simulated velocity, temperature by the RNG k- turbulent model and the measured data were quite good. A discrete trajectory model was adopted to simulate the particle movement in a room. The results showed that the flow patterns created by different ventilation modes have great influence on the fates of particles. The particle concentrations for the entire room and for the breathing zone under stratum ventilation are less than that under displacement ventilation, which implies that the risk of particle inhalation under stratum ventilation is less than that under displacement ventilation. The deposited particle mass on room walls and furniture surfaces under stratum ventilation is greater than that under displacement ventilation. The particle mass deposited on the floor plays an important role in the process of particle deposition. The mass of particles that escaped under stratum ventilation was less than that under displacement ventilation. Moreover, the influence of particle diameter on particle dispersion is also considered in the present paper.

Real Risk

Lange, J.H., Mastrangelo, G. — Wed, 10 Jun 2009 05:55:43 PDT

Response Coefficient: A New Concept to Evaluate Ventilation Performance with ''Pulse'' Boundary Conditions

Xianting Li, , Fenfei Zhu, — Wed, 10 Jun 2009 05:55:43 PDT

Releasing a ''pulse'' tracer contaminant at a given point, either in the air supply or in the indoor space, and monitoring its transient distribution in a steady-state flow field, allows the performance of the air distribution to be evaluated. Two nondimensional indices have been defined, Response Coefficient to Supply Air (RCSA) and Response Coefficient to Contaminant Source (RCCS), to characterize spatial and temporal distribution under different air distribution patterns. To demonstrate their characteristics a 2D ventilated room was numerically analyzed. The results show that RCSA at each location (except the inlet) and RCCS at each location in the room (except the contaminant source) initially increase, then decrease, and become zero when time is long enough; RCSA ``records'' the characteristics of the flow field. There will be only one maximum response coefficient value under a piston flow field, while under a flow field with recirculation, there will be several, which may be used to evaluate the airflow pattern; RCCS contains information on the contaminant source position under a specific flow field. The relative positions of the contaminant source and the monitoring points determine response curves, which may be used to judge the position of a contaminant source; accumulation of RCSA and RCCS will become constant when time is long enough. The accumulation value of RCSA at any location indoors is 1, while accumulation values of RCCS at different locations differ from each other, but are determined by the relative position of the contaminant source and the location.

Ventilation Control of Indoor Transmission of Airborne Diseases in an Urban Community

Xiaolei Gao, , Yuguo Li, , Leung, G. M. — Wed, 10 Jun 2009 05:55:43 PDT

Following the recent severe acute respiratory syndrome epidemics and worldwide concern about the next pandemic, whether influenza or multiple drug resistant tuberculosis, has underlined the importance of effective interventions into airborne disease transmission in indoor environments in a community. The engineering control measures available include ventilation dilution, use of high-efficiency particulate air filters in a room or in the heating, ventilation, and air-conditioning (HVAC) system, and use of ultraviolet germicidal irradiation devices in ceiling area of a room or in the HVAC system. These methods are known to be effective in controlling or delaying airborne disease transmission in a single enclosure in both healthcare facilities and the community. However, there have been no studies of their relative effectiveness at the community level. This paper presents mathematical modeling of some engineering control strategies with a focus on ventilation and corresponding analysis of their relative effectiveness compared with other public health interventions in disease control in indoor environments at the community level. The results should help us to determine the most effective intervention strategies. We conclude that the engineering intervention methods such as building ventilation can be as effective as public health interventions and the ventilation rates specified in the existing standards such as ASHRAE 62 may be too low for the purpose of preventing or controlling airborne infectious diseases in indoor environments.

Smoke Flow in Chinese Kangs

Zhi Zhuang, , Yuguo Li, , Bin Chen, — Wed, 10 Jun 2009 05:55:43 PDT

Chinese kangs are widely used today, in nearly 85% of rural homes by 175 million people in Northern China. While Chinese kangs are a potentially energy sustainable solution for home heating, existing systems are characterized by their poor energy efficiency and significant concerns about the impact of indoor air pollution in homes caused by smoke backflow or smoke leakages. Existing kang designs are based on the intuition and historical accumulation of past craftsmanship experiences. As the first attempt, a macroscopic thermal-fluid approach is used to model the airflow and heat transfer process of an elevated kang with a focus on smoke flow. This model considers nonlinear interaction of thermal buoyancy force, wind force and heat transfer from kang plates and chimney walls. Five parameter groups are identified for characterizing the kang systems to guide the kang smoke flow design. Our work has explained the so-called smoke backflow phenomenon that can lead to serious indoor air quality problems in rural homes and based on the results, we have provided some design recommendations for avoiding smoke backflowand for enhancing energy efficiency by increasing the heat utilization of the kang body.

A Study on the Application of a Ceiling Plenum Ventilation System in an Apartment House

Yang, J.-H., Seok, H.-T., Lee, S.-J. — Wed, 10 Jun 2009 05:55:43 PDT

Currently, an air change rate (0.7 h^-1) and spring cooler installation must be considered when building an apartment house in Korea, in order to comply with the Building Standards and the Fire Service Act. In accordance with a series of legal requirements for Korean apartment houses, the improvement of the availability of ceiling space and space for working ease is required in apartments by installing a new ventilation system in the ceiling space to accommodate a spring cooler. In this study, a new ventilation system is suggested, called the ceiling plenum ventilation system. To introduce this system in the residential section of a residential-commercial complex building, a constant air volume system or combination air volume system with a 150 mm supply opening and branch duct must be used. For residential-commercial complex buildings with lower ceilings or for general apartment houses, the effective area of the supply opening of the rooms and the air supply duct at the total heat exchanger side must be increased and a combination air volume system must be used.

Influence of the Convective Surface Transfer Coefficients on the Heat, Air, and Moisture (HAM) Building Performance

Steskens, P. W.M.H., Janssen, H., Rode, C. — Wed, 10 Jun 2009 05:55:43 PDT

Current models to predict heat, air, and moisture (HAM) conditions in buildings assume constant boundary conditions for the temperature and relative humidity of the neighboring air and for the surface heat and moisture transfer coefficients. These assumptions may introduce errors in the predicted HAM conditions. The paper focuses on the influence of the interior surface heat and moisture transfer coefficients, and investigates its effect on the hygrothermal performance. The parameter study showed that the magnitude of the convective surface transfer coefficients has a relatively large influence on the predicted hygrothermal conditions at the surface of a building component and on the heat and vapor exchange with the indoor environment.

Investigation of Mold Growth in Indoor School Buildings by Monitoring Outgassed Methyl Benzoate as a MVOC Biomarker

Parkinson, D.-R., Churchill, T. J., Wady, L., Pawliszyn, J. — Wed, 10 Jun 2009 05:55:43 PDT

An investigation of 16 classrooms in 4 randomly selected schools (children age 6—12) and 7 different places at the University of Waterloo, Waterloo, ON, Canada and 4 locations at Sir Wilfred Grenfell College, MUN, Corner Brook, NL, Canada were conducted to quantify emitted methyl benzoate concentrations. Methyl benzoate — as a metabolic biomarker of mold growth — has potential as an indicator for other volatile organic compound emissions outgassed by bacteria and molds. A variety of solid and indoor air grab samples were taken from the selected locations and were immediately analyzed by solid phase microextraction and gas chromatography/mass spectrometry. By this rapid method, methyl benzoate concentrations in solid samples were found to range: 5—69 and 6—22 ppb for schoolrooms and university rooms, respectively. For air samples, methyl benzoate (quantitation limit 2 ppb) was not detected in the schools, however at the universities; concentrations were as high as 25 ppb. This study supports that methyl benzoate may have use, as an indicator of mold growth, in indoor air research.

Airborne Fungi in Wood and Wood Based Board Factories

Sivrikaya, H., Kara, O. — Wed, 10 Jun 2009 05:55:43 PDT

This study was a comparative investigation of the isolation and identification of airborne fungi between wood processing and melamine coated board processing factories. Isolation of airborne fungi was performed in four small sized enterprises engaged in wood processing and melamine coated board processing, located in the West Black Sea region of Turkey. Petri dishes containing Rose-Bengal streptomycin agar were exposed to air in the plants for 15 minutes. The highest fungal colony counts were observed in plant D, where the average value was 72 cfu per plate. Penicillium was the most widespread species identified in all the plants. Aspergillus fumigatus, which has major importance among the airborne fungi because it can cause health problems for workers, was only isolated in plant A.

Use of Gamma Ray Spectroscopy Measurements for Assessment of the Average Effective Dose from the Analysis of 226Ra, 232Th, and 40K in Soil Samples

Mehra, R. — Wed, 10 Jun 2009 05:55:43 PDT

The activity concentrations of the natural radionuclides: ²³⁸Ra , ²³²Th, and ⁴⁰K were measured in soil samples collected from two districts of the Punjab. A HPGe detector, based on high-resolution gamma spectrometry system was used for their measurement. The range of activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in the soil from the studied areas varied from 25 Bq·kg^-1 to 42 Bq·kg^-1, 72 Bq·kg^-1 to 130 Bq·kg^-1, and 229 Bq·kg^-1 to 385 Bq·kg^-1 with overall mean values of 32 Bq·kg^-1, 91 Bq·kg^-1,and 289 Bq·kg^-1, respectively. Radium equivalent activities were calculated for the samples to assess the radiation hazards arising due to the use of these soils in the construction of dwellings. The absorbed dose rate calculated from activity concentration of ²²⁶Ra, ²³²Th, and ⁴⁰K ranges between 12 and 19, 45, and 81, and 9 and 16 nGy·h^-1, respectively. The total absorbed dose in the study area ranged from 70 nGy·h^-1 to 111 nGy·h^-1 with an average value of 84 nGy·h^-1. The calculated values of external hazard index (H_ex) for the soil samples ranged from 0.41 to 0.67. Since these values are lower than unity the soil from these regions is safe and can be used as a construction material without posing any significant radiological threat to population according to the Radiation Protection 112 (European Commission, 1999) report. The corresponding average annual effective dose for indoors and outdoors was 0.41 and 0.11 mSv, respectively.

Keeping the Lights On

Hoskins, J.A. — Fri, 27 Mar 2009 07:30:11 PDT

Evaluation of Modeling and Measurement Techniques of Ultraviolet Germicidal Irradiation Effectiveness -- Towards the Design of Immune Buildings

Bei Wang, , Mortazavi, R., Haghighat, F. — Fri, 27 Mar 2009 07:30:11 PDT

While concerns about occupants' health, comfort, energy consumption, and environment are becoming a main design consideration for ventilation systems there are also threats to public safety and security that cannot be overlooked and need to be taken into consideration. A sudden release of chemical and biological agents can pose a safety and security threat to public buildings and can cause injuries and loss of life. Recently air-cleaner technology has been introduced for air sterilization and purification in industrial buildings and hospitals due to its long life, functionality, and sustainability. However this technology has not been applied to the nonindustrial built environment in general, and the possibility of a sudden release of chemical or biological agents in particular has not been addressed. This paper presents a detailed review of previous studies on the measurement of ultraviolet germicidal irradiation effectiveness for decontamination, particularly as related to rooms and mechanical systems (ducting) in buildings. It also discusses the methods used to model the space, as well as the measurements and methods used to measure its performance followed by a comparison of the results and discussion of the possible causes of variance in reported data.

Ventilation Parameters and Thermal Comfort of Naturally and Mechanically Ventilated Offices

Daghigh, R., Adam, N.M., Sahari, B.B. — Fri, 27 Mar 2009 07:30:11 PDT

This paper discusses thermal comfort for a postgraduate study office room in the Mechanical Engineering Department of University Putra Malaysia (UPM), which maybe either naturally ventilated or air-conditioned. Thermal comfort variables were assessed by survey of sensation of the indoor climate. Tracer gas analysis, based on the concentration decay method, was employed to determine air exchange rate, age of air, and air exchange effectiveness (AEE). When the air conditioner was working the study office had conditions within the comfort zone of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 55; and the occupants reported they were ``slightly cool.'' Objective data analysis showed that the office was thermally comfortable. Under naturally ventilated conditions objective results showed that the office was uncomfortable but a subjective study revealed that students found the conditions to be ``slightly warm.'' The neutral temperature showed a wider thermal comfort range for Malaysian students than that suggested by ASHRAE Standard 55-1992, which indicates that Malaysians are acclimatized to higher environmental temperatures. However, the result is in line with the current version of ASHRAE Standard 55-2004 that includes an adaptive comfort standard that allows warmer indoor temperatures for warmer climate zones.

The results of a ventilation study indicated air flow patterns in the occupied zones, which approximated to ``perfect mixing'' under both ventilation conditions. The measured air exchange rate also indicated that the provision of outside air for ventilation was adequate when the room was mechanically ventilated (air-conditioned). Results of over 50 survey responses to thermal comfort questions in the study room at UPM are given.

Indoor Environmental Quality Benchmarks for Air-conditioned Offices in the Subtropics

Mui, K.W., Wong, L.T., Hui, P.S. — Fri, 27 Mar 2009 07:30:11 PDT

Indoor environmental quality (IEQ) of air-conditioned offices could be benchmarked by the occupants' acceptability. This study proposes a five-star IEQ benchmarking system based on an expression of the occupants' overall IEQ acceptance on thermal comfort, indoor air quality and aural and visual comfort. By using an earlier proposed IEQ index, the occupants' adaptive response of clothing adjustment for the perceived thermal environment was reported in order to determine the overall IEQ acceptance. The benchmarking parameter of a star rating system and the IEQ index were applied to express relative IEQ performance of air-conditioned offices in Hong Kong. The IEQ performance of some recommended environmentally sustainable policies for ``Excellent'' and ``Good'' offices was evaluated and compared with the existing offices. The probable IEQ in some Hong Kong offices were determined by Monte Carlo simulations from reports of surveyed studies. Among the existing office stock, results have shown that in offices which are renovated to the ``Excellent'' and ``Good'' IEQ criteria recommended by some policies, the IEQ acceptances for 5-star IEQ benchmarked offices are namely 0.95, 0.94, and 0.92, while for 3-star IEQ benchmarked offices, they are 0.89, 0.89, and 0.67 accordingly. The proposed star rating system would serve as a quantitative measure of IEQ for air-conditioned office environment in Hong Kong and given selected model parameters, it would be a useful reference for similar environments where the evaluation of an occupant is expected.

Determination of Carbon Monoxide Levels in Coffee Shops in Ankara

Tekbas, O. F., Gulec, M., Odabasi, E., Vaizoglu, S. A., Guler, C. — Fri, 27 Mar 2009 07:30:11 PDT

Indoor environments are where people spend 80—90% of their time. They are at their riskiest in terms of air pollution when smoking is not prohibited and various combustion and/or cooking applications are performed. If such environments are where people live or work, or are recreation facilities open to everybody, experience has shown that pollution levels to which they are exposed can reach levels that are a threat to their health.

This study is an investigation of coffee shops, which are such communal environments, identified according to factors such as clientele and physical accommodation. The pollution parameter chosen was the level of carbon monoxide in the air, evaluated according to its compliance to the existing standards and setting forth measures that might be taken against probable health risks.

The study was performed in 384 coffee shops selected randomly from amongst those (N = 7646) located in five central municipal districts of Ankara province. Most of the environments investigated were observed to have deficiencies in respect of accident risk, hygienic features and accommodation conditions. The mean carbon monoxide level was found to be below the short and long-term threshold values. However, CO levels above long-term threshold levels were observed in 34% of the coffee shops.

In conclusion, the environments investigated were found to pose risks in terms of both accommodation conditions and indoor environment air quality. It was concluded that these risks, which could affect the health of workers and clientele, could be eliminated by environmental health measures.

Modeling the Occurrence of Nitrogen Oxides Indoors

Vilcekova, S., Senitkova, I. — Fri, 27 Mar 2009 07:30:11 PDT

The contamination of indoor air is largely from the use of gas for heating and cooking appliances. A comprehensive analysis of indoor air pollution by nitrogen oxides shows that the extent of indoor air pollution and consequent exposure varies as a result of many factors mainly the differing distribution of appliances and their level of use. This study aims to formulate a mathematical model for the production of nitrogen oxides indoors. The physical processes that determine the concentrations of indoor nitrogen oxides as a function of outdoor concentrations, indoor emission rates, and building characteristics have been mathematically described. The mathematical model developed has been parameterized for typical Slovak residences. The modeling of the occurrence of indoor nitrogen oxides and verification of the model are presented in this paper.

Indoor Volatile Organic Compounds in Atopy Patients' Houses in South Korea

Fri, 27 Mar 2009 07:30:11 PDT

This study was undertaken to determine the concentrations of volatile organic compounds (VOCs) in the indoor air of atopy patients' (atopic dermatitis 50, allergic asthma 36) and control houses (28 nonpatients). A goal of this study was also to investigate whether indoor VOCs were risk factors for the development of atopic sensitization. Eleven alkanes, 13 aromatics, 7 chlorinated hydrocarbons, 3 terpenes, and 15 aldehyds were measured from 10 March to 15 June, 2006. Aldehyde compounds are the most abundant chemical group in all indoor air, followed by aromatic compounds. The geometric mean concentrations of total VOC (TVOC) in indoor air in atopic dermatitis and allergic asthma patients' houses were 317.1 and 219.2 mg m ^-3, respectively. However, TVOC concentrations did not differ significantly between control and patient houses in indoor and outdoor air. The geometric mean concentrations of benzene, ethylbenzene (p<0.05), o-xylene, m-, p-xylene, styrene, levels of 1,3,5-trimethylbenzene and formaldehyde (p<0.01) in the indoor air of houses of patients with atopic dermatitis, and levels of o-xylene and 1,3,5-trimethylbenzene (p<0.01) in houses of allergic asthma patients were significantly higher than those in control houses. The multiple linear regression model in this study indicated several indoor origins of VOCs. House age and floor or wall coverings that had been refurbished within 1 year were correlated with higher concentrations of formaldehyde. Limonene and pinene concentrations were significantly increased by the replacement of furniture and the use of cleaning products. The type of heating system was significantly associated with indoor benzene, toluene, ethylbenzene, nonane, decane, and undecane concentrations in atopy patient houses.

Composition of Household Dust in Semi-urban Areas in Malaysia

Fri, 27 Mar 2009 07:30:11 PDT

A study of household dust composition was conducted in a semi-urban area around Kajang and Bandar Baru Bangi Selangor, Malaysia. Samples of household dust were collected from 31 randomly selected houses using a vacuum cleaner equipped with a changeable dust bag. Parameters analysed were anions (Cl^-, SO₄^2- , and NO₃- ), cations (K⁺, Ca²⁺, and Mg²⁺), and heavy metals (Cd, Fe, Ni, and Pb) to deduce the possible sources and evaluate the toxicity of indoor dust. The concentration of each parameter was compared to the concentration of street dust collected outside the houses. The results showed that the composition of anions was dominated by Cl^- followed by SO₄^2- and NO₃-; cations concentration by the sequence of Ca²⁺ > K⁺ > Mg²⁺ and for heavy metals concentration, Pb was present in the highest concentration followed by Ni > Fe > Cd > Zn. The study also showed that the concentration of most parameters analyzed were higher in household dust than street dust, suggesting that the composition of household dust is more closely related to indoor activities and the environment.

Assessment of Air Change Rates in Chemical Laboratories

Chien, Y.-C., Chang, C.-P., Lo, C.-P. — Fri, 27 Mar 2009 07:30:11 PDT

By performing a set of controlled experiments and field measurements, this study investigated ventilation conditions in chemical laboratories in universities, as well as the impact of various ventilation measures on air change rate (ACR). The controlled study was conducted in one research laboratory. On/off air-conditioning, a fume hood, local exhaust, and an open door were the test variables. The field study measured ACR in 24 chemical laboratories at two universities. Ventilation in each laboratory was assessed by estimating the ACR using CO₂-decay approaches. Controlled study results indicate that air-conditioning and local exhaust did not significantly impact the ACR, whereas use of a chemical hood or open door significantly (p < 0.05) increased the ACR by 4.6- and 3.2-fold, respectively. Field measurements indicate that the average ACR for laboratories with air-conditioning and closed windows, air-conditioning with windows partially closed, and no air-conditioning with windows open and fans were 2.18, 10.1, and 23.8 (h^-1), respectively. Overall, 38% of chemical laboratories measured in this study, especially those using air-conditioning with closed windows (~100%), did not meet the Occupational Safety and Health Administration laboratory ventilation requirements of four air exchanges per hour. Opening windows, at least partially, improved the ACR.

Improving the Environmental Controls at a Homeless Shelter to Assist in Reducing the Probability of Airborne Transmission of Mycobacterium tuberculosis: A Case Study

Coffey, C. C., Hudnall, J. B., Martin, S. B. — Fri, 27 Mar 2009 07:30:11 PDT

This study describes a survey of environmental controls conducted by the National Institute for Occupational Safety and Health (NIOSH) at the Salvation Army Harbor Light Center homeless shelter in the City of St. Louis, Missouri. The Missouri Department of Health and Senior Services (MO DHHS) had epidemiologically linked 19 cases of active tuberculosis (TB) to the shelter. MO DHSS requested NIOSH to determine whether improvements could be made to the environmental controls to help reduce the probability of airborne transmission of TB at the shelter. NIOSH investigators conducted thorough inspections of the shelter's air-handling units (AHUs) and evaluated airflow rates. NIOSH recommended higher efficiency filters be used in the AHUs and installation of ultraviolet lights.