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Choi H.,University at Albany | Byrne S.,University at Albany | Larsen L.S.,Danish Technological Institute DTI | Sigsgaard T.,University of Aarhus | And 5 more authors.
Indoor Air | Year: 2014

Qualitative reporting of home indoor moisture problems predicts respiratory diseases. However, causal agents underlying such qualitative markers remain unknown. In the homes of 198 multiple allergic case children and 202 controls in Sweden, we cultivated culturable fungi by directly plating dust, and quantified (1-3, 1-6)-β-d-glucan and ergosterol in dust samples from the child's bedroom. We examined the relationship between these fungal agents and degree of parent or inspector-reported home indoor dampness, and microbiological laboratory's mold index. We also compared the concentrations of these agents between multiple allergic cases and healthy controls, as well as IgE-sensitization among cases. The concentrations of culturable fungal agents were comparable between houses with parent and inspector-reported mold issues and those without. There were no differences in concentrations of the individual or the total summed culturable fungi, (1-3, 1-6)-β-d-glucan, and ergosterol between the controls and the multiple allergic case children, or individual diagnosis of asthma, rhinitis, or eczema. Culturable fungi, (1-3, 1-6)-β-d-glucan, and ergosterol in dust were not associated with qualitative markers of indoor dampness or mold or indoor humidity. Furthermore, these agents in dust samples were not associated with any health outcomes in the children. © 2013 John Wiley & Sons A/S.

Kassman H.,Vattenfall | Kassman H.,Chalmers University of Technology | Bafver L.,Technical Research Institute of Sweden | Amand L.-E.,Chalmers University of Technology
Combustion and Flame | Year: 2010

This paper is based on results obtained during co-combustion of wood pellets and straw in a 12MW circulating fluidised bed (CFB) boiler. Elemental sulphur (S) and ammonium sulphate ((NH4)2SO4) were used as additives to convert the alkali chlorides (mainly KCl) to less corrosive alkali sulphates. Their performance was then evaluated using several measurement tools including, IACM (on-line measurements of gaseous alkali chlorides), a low-pressure impactor (particle size distribution and chemical composition of extracted fly ash particles), and deposit probes (chemical composition in deposits collected). The importance of the presence of either SO2 or SO3 for gas phase sulphation of KCl is also discussed. Ammonium sulphate performed significantly better than elemental sulphur. A more efficient sulphation of gaseous KCl was achieved with (NH4)2SO4 even when the S/Cl molar ratio was less than half compared to sulphur. Thus the presence of gaseous SO3 is of greater importance than that of SO2 for the sulphation of gaseous KCl. © 2010 The Combustion Institute.

Choi H.,University at Albany | Schmidbauer N.,Norwegian Institute For Air Research | Bornehag C.-G.,Technical Research Institute of Sweden | Bornehag C.-G.,Karlstad University
Environmental Research | Year: 2016

Background: The question regarding the true sources of the purported microbial volatile organic compounds (MVOCs) remains unanswered. Objective: To identify microbial, as well as non-microbial sources of 28 compounds, which are commonly accepted as microbial VOCs (i.e. primary outcome of interest is σ 28 VOCs). Methods: In a cross-sectional investigation of 390 homes, six building inspectors assessed water/mold damage, took air and dust samples, and measured environmental conditions (i.e., absolute humidity (AH, g/m3), temperature (°C), ventilation rate (ACH)). The air sample was analyzed for volatile organic compounds (μg/m3) and; dust samples were analyzed for total viable fungal concentration (CFU/g) and six phthalates (mg/g dust). Four benchmark variables of the underlying sources were defined as highest quartile categories of: 1) the total concentration of 17 propylene glycol and propylene glycol ethers (σ17 PGEs) in the air sample; 2) 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (TMPD-MIB) in the air sample; 3) semi-quantitative mold index; and 4) total fungal load (CFU/g). Results: Within severely damp homes, co-occurrence of the highest quartile concentration of either σ17 PGEs or TMPD-MIB were respectively associated with a significantly higher median concentration of σ 28 VOCs (8.05 and 13.38 μg/m3, respectively) compared to the reference homes (4.30 and 4.86 μg/m3, respectively, both Ps ≤0.002). Furthermore, the homes within the highest quartile range for σ fungal load as well as AH were associated with a significantly increased median σ 28 VOCs compared to the reference group (8.74 vs. 4.32 μg/m3, P=0.001). Within the final model of multiple indoor sources on σ 28 VOCs, one natural log-unit increase in summed concentration of σ17 PGEs, plus TMPD-MIB (σ 17 PGEs + TMPD-MIB) was associated with 1.8-times (95% CI, 1.3-2.5), greater likelihood of having a highest quartile of σ 28 VOCs, after adjusting for absolute humidity, history of repainting at least one room, ventilation rate, and mold index (P-value =0.001). Homes deemed severely mold damaged (i.e., mold index =1) were associated with 1.7-times (95% CI, 0.8-3.6), greater likelihood of having a highest quartile of σ 28 VOCs, even though such likelihood was not significant (P-value =0.164). In addition, absolute humidity appeared to positively interact with mold index to significantly elevate the prevalence of the highest quartile category of σ 28 VOCs. Conclusion: The indoor concentration of σ 28 VOCs, which are widely accepted as MVOCs, are significantly associated with the markers of synthetic (i.e. σ17 PGEs and TMPD-MIB), and to less extent, microbial (i.e., mold index) sources. © 2016 Elsevier Inc.

Haller M.Y.,University of Applied Sciences Rapperswil | Haberl R.,University of Applied Sciences Rapperswil | Persson T.,Dalarna University | Bales C.,Dalarna University | And 3 more authors.
Energy and Buildings | Year: 2013

Objective For the evaluation of the energetic performance of combined renewable heating systems that supply space heat and domestic hot water for single family houses, dynamic behaviour, component interactions, and control of the system play a crucial role and should be included in test methods. Methods New dynamic whole system test methods were developed based on "hardware in the loop" concepts. Three similar approaches are described and their differences are discussed. The methods were applied for testing solar thermal systems in combination with fossil fuel boilers (heating oil and natural gas), biomass boilers, and/or heat pumps. Results All three methods were able to show the performance of combined heating systems under transient operating conditions. The methods often detected unexpected behaviour of the tested system that cannot be detected based on steady state performance tests that are usually applied to single components. Conclusion Further work will be needed to harmonize the different test methods in order to reach comparable results between the different laboratories. Practice implications A harmonized approach for whole system tests may lead to new test standards and improve the accuracy of performance prediction as well as reduce the need for field tests. © 2013 Elsevier B.V. All rights reserved.

Bystrom A.,Lulea University of Technology | Wickstrom U.,Lulea University of Technology | Wickstrom U.,Technical Research Institute of Sweden | Veljkovic M.,Lulea University of Technology
Applied Mechanics and Materials | Year: 2011

The concept of Adiabatic Surface Temperature (AST) opens possibilities to calculate heat transfer to a solid surface based on one temperature instead of two as is needed when heat transfer by both radiation and convection must be considered. The Adiabatic Surface Temperature is defined as the temperature of a surface which cannot absorb or lose heat to the environment, i.e. a perfect insulator. Accordingly, the AST is a weighted mean temperature of the radiation temperature and the gas temperature depending on the heat transfer coefficients. A determining factor for introducing the concept of AST is that it can be measured with a cheap and robust method called the plate thermometer (PT), even under harsh fire conditions. Alternative methods for measuring thermal exposure under similar conditions involve water cooled heat flux meters that are in most realistic situations difficult to use and very costly and impractical. This paper presents examples concerning how the concept of AST can be used in practice both in reaction-to-fire tests and in large scale scenarios where structures are exposed to high and inhomogeneous temperature conditions. © (2011) Trans Tech Publications.

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