SYTTY
Epidemiological evidence shows that building moisture and microbial growth are associated with respiratory symptoms related to inflammatory reactions, ie. irritation, infections and asthma. At present, it is not known which are the most important causative microbes able to induce these adverse effects, what are the specific cellular effects and, particularly, what are the mechanisms of them. These data are, however, needed for proper risk assessment of the moldy house problem and the measures taken to solve it. There is an urgent need on experimental work on cell cultures and laboratory animals with the microbes isolated from moldy buildings suspected to be harmful. Such data is at present to most extent missing but the present plan is aimed to provide it comprehensively.
We have recently observed that 1) streptomycetes induce production of inflammatory mediators i.e. nitric oxide (NO), cytokines and reactive oxygen species (ROS) and cause cell death in mice macrophages in vitro, 2) these responses are not dependent on the viability of the spores of streptomycetes, and preliminary: 1) growth conditions play an important role in the ability of these microbes to induce the production of inflammatory mediators and to cause cytotoxicity 2) streptomycetes produce NO and cause cytotoxicity also in human lung epithelial cell line, and 3) the strains of the streptomycetes active in vitro also elevate the same inflammatory mediators in bronchoalveolar lavage fluid (BAL) in rats after an intratracheal instillation to lungs. Altogether, these results suggest that certain moldy house microbes are able to induce inflammatory responses and/or to cause cell death in mammalian cells. This may play a central role in the cascade of events leading to the adverse health effects.At this phase, it is inevitable to study which other microbes characteristic to moldy houses cause similar effects and what are the effects of these microbes in lungs.
The overall aim of the study is to find out which microbes among the mixed population of the microbes present in the moldy houses are able to cause adverse respiratory health effects and what are the mechanisms of them. The focus is on inflammatory responses and cytotoxicity in human and mice cells and local toxicity in lungs and effects on respiration in animals. Effects of six typical microbes isolated from moldy buildings are studied: Streptomyces anulatus, Sreptomyces californicus, Aspergillus versicolor, Stachybotrys atra, Fusarium, and mycobacteria. This plan evaluates effects of these microbes in vitro in both human and mice cell cultures, deepens our previous work with streptomycetes to new mechanisms and expands studies to animals in vivo. The specific aims for the in vitro studies are 1) to study in detail the effects and the mechanisms of cell death and inflammatory responses in human and mice macrophages, induced by these microbes and their combinations, 2) to study cytotoxicity and the inflammatory responses induced by these microbes in human lung epithelial cells 3) to study the relation between growing conditions of the microbes and their ability to induce inflammatory responses and cytotoxicity. The specific aims for in vivo studies are 1) to study effects of streptomycetes and the microbes proving to be harmful in in vitro studies in lungs of mice after intranasal instillation (inflammation, local toxicity in lungs), 2) to identify the target cells of effects in the airways 3) to evaluate the effects of the microbes on respiration in guinea pigs after intratracheal instillation. This study identifies potentially harmful microbes present in moldy houses to cause respiratory effects, describes those effects in the lungs of laboratory animals and elucidates the cellular mechanisms of moldy house effects. These data will form a new fundamental basis for risk assessment of the health effects of those microbes and help to develop methods for biomonitoring of harmful microbial exposure. Identification of the most harmful microbes is also the basis for decisions to solve the moldy house problems.
In vitro studies: to investigate the effects induced by occupational exposure to microbes present in moldy houses on nasal functions and production of inflammatory mediators in nasal lavage fluid (NAL) cells in healthy and symptomatic subjects.
Key words: Moldy houses, inflammation, NO, cytokines, cytotoxicity, reactive oxygen species, macrophages, epithelial cells, Streptomyces anulatus, Sreptomyces californicus, Aspergillus versicolor, Stachybotrys atra, Fusarium, mycobacteria.
Consortium: Moisture, mould and health
Moisture and mould problems of buildings are associated with respiratory symptoms and diseases. The association between the building damage and the adverse health effects is well known, but little is known about the mechanisms of the diseases and about the actual exposure causing these health effects. The exposure has been characterized in many indirect methods. It has been shown that concentrations of viable fungi and bacteria and microflora of the indoor air in a damaged building differs from that of a normal building. However, viable microbes only comprise about 10% of the total number of biological particles in indoor air, and thus are a proxy of the real microbial exposure, the nature and quality of which is largely unknown so far. Toxic components derive from fungi and bacteria growing in building materials, but it has not been shown how the exposure to these components via indoor air takes place. The principal aim of this study is to find out whether the exposure to bioaerosols and fine particles of individuals with symptoms typical to mould exposure differs from that of matched control individuals. The detailed aims are:
Bioaerosol and particle sampling is made with button samplers developed in the University of Cincinnati.The concentration of collected particles will be analyzed gravimetrically. Viable microorganisms of filter are cultured and the total number of biological particles counted with an epifluorescence microscope.
Toxicological studies: A nasal lavage fluid (NAL) sample will be collected from each individual after the sampling period. Production of inflammatory mediators (NO, cytokines: TNFalfa, IL-1, IL-5, IL-6, IL-10) in the NAL cells will be analyzed.
Key words: bioaerosol, exposure, moisture, mould, microbes, health effect
Research site: National Public Health Institute, Division of Environmental Health, Laboratories of Environmental Microbiology, Air Research and Toxicology
Consortium: Moisture, Mould and Health
- Air Research Laboratory: Sari Alm, M.Sc., Matti Jantunen, Ph.D.
- Laboratory of Toxicology: Maija-Riitta Hirvonen, Ph.D.
- Unit of Environmental Epidemiology: Tuula Husman, MD, Ph.D.
University of Cincinnati, Aerosol Research and Exposure Assessment Laboratory:
Tiina Reponen, Ph.D.
Sergey Grinshpun, Ph.D.
Klaus Willeke, Ph.D.
Moisture and mould problems in school buildings cause exposure to biological indoor air pollutants for the school children, teachers and other personnel, resulting in respiratory symptoms and infections and in some cases, even increased incidence of asthma. A number of occupational diseases caused by biological indoor air pollutants have been recently recognized among teachers and personnel of moisture -damaged schools. Indoor air quality and health problems are common, and the municipalities are putting remarkable resources on the repair measures but little documented data is so far available about the effects of the repair measures on the users health and thus on the cost effectiveness of the repairs. This intervention study is designed to increase our understanding about the effects of the repair measures on the school students health and exposure. The overall aim of the study is to find out whether the moisture and mould repairs of the school buildings have an effect on the exposure to indoor air pollutants, and on the prevalence of respiratory symptoms and diseases of the school students Both the health status and exposure are measured in detail before the repairs are started, and the measurements will be repeated after the completion of the repairs. The study cohort consists of elementary school children and high school students (N=2500). The detailed objectives are:
This study is linked with the follow-up of the health of the personnel, the technical monitoring of the effectiveness of the repairs, (financed by the Finnish Fund of Occupational Health and Tekes), and several projects of the Consortium studying the exposure to bioaerosols and mechanisms of the health effects. The results will provide tools
Tuula Husman, MD: clinical studies, epidemiology
Maija-Riitta Hirvonen, Ph.D.: in vitro studies
Tampere University of Technology, Department of Building Technology,
Ralf Lindberg, professor: building technology
University of Kuopio, Department of Environmental Sciences, Pentti
Kalliokoski, professor: occupational health
University Hospital of Kuopio, Matti Korppi, MD: clinical studies (children)
Towns of Kuopio and Saarijärvi and municipalities of Siilinjärvi,
Kiuruvesi and Tuusniemi as owners of the school buildings and as the responsible
authorities are collaborating in the project.
Graduate students in the project:
Ulla Haverinen, M.Sc
Anne Hyvärinen, M.Sc
Teija Meklin, M.Sc
Mika Toivola, B.Sc:
Mikko Vahteristo, M.Sc
Taina Taskinen, MD
Moisture and mould problems have been assessed as a major problem in
the modern building stock, and their repair and
prevention are one of the most important challenges in the research
of building technology. As these problems often lead to
health complaints among the users, the prerequisite of a successful
repair process is the identification of the ultimate causes of
the moisture accumulation and the development of reasonable repair
methods. This work must go in parallel with the
health-related research including the prevention of diseases and wellbeing
of the occupants. Suitable methods for the
follow-up of the success of the repairs are urgently needed. The technical
criteria of the repair planning may somewhat differ
from the health-based criteria. For example, a material previously
contaminated with mycotoxins may still be technically
usable, but not acceptable for health-based reasons.
The aim of the study is to develop method for monitoring the success
of moisture and mould repairs. The strategy is to
combine the technical and health-based approach. The material for the
study will be collected from large repair projects with
an intervention-type studyesign. The exposure and health status of
the occupants will be followed throughout the process and
the technical repair solutions will be carefully documented.
The project is a joint effort between National Public Health Institute
(KTL), Insinööritoimisto Mikko Vahanen Oy and
Kiinteistön Tuottoanalyysit Oy.
In Finland, half of all homes have a moisture problem, and microbial growth occurs in 20 percent of the cases. Altogether 500 000 individuals are annually exposed to indoor bioaerosols. Recent evidence suggests that this exposure may cause CNS effects in addition to adverse effects in the respiratory system. In fact, adverse CNS effects after exposure to bioaerosols, i.e. bacteria, fungi, molds, microbial cell wall components or metabolic products of microbes, have been found in experimental animals and humans. Available evidence indicates that both neuronal and glial cells can be affected by this exposure. The effects of microbial toxins on the CNS are of particular importance because even a small excess morbidity of brain diseases may imposes a major burden on the health care system and the society at large. The focus of this research is to increase understanding of the role of microbial toxins in bioaerosol-induced CNS health effects. The overall objective is to study the mechanisms whereby LPS, and toxins of Fusarium multiforme, fumonisin B1, and of Stachybotrus chartarum (trichothecenes) activate neuronal and glial cells. The specific aims: 1. To study cell activation by the toxins; 2. To study altered gene expression by these toxins; 3. to study mechanisms of apoptosis induced by these toxins; and 4. to explore the role of cytokine production in the effects of these toxins. Methods: ROS and NO production will be studied with a fluorescent probe, and photometrically. Cell death will be analysed fluorometrically, and apoptosis with DNA fragmentation and with a fluorescent probe. Transcription factor binding will be studied with an EMSA assay, and cytokine production with an ELISA assay. Expression of iNOS is explored at protein, and of an apoptosis promoter BAX, and an antiapoptotic gene Bcl-2, at mRNA level. Also caspase expression (mRNA level) and activity will be studied. We expect that the proposed studies will provide valuable information of the mechanisms of effects of microbial toxins in neuronal and glial cells. This information can be utilized in assessing health hazard of bioaerosol exposure, and in evaluating the need of human epidemiological studies.
Key-words: Microbial toxins-neuronal cells-oxidative stress-transcription factors-apoptosis-cell death
Abstract Microbial aerosols in houses suffering from excessive humidity are a serious public health problem. So far the main attention has been focused to the sensitizing properties of microbes and their degradation products. However, the microbes present in problem houses (molds and actinomycetes) are known producers of bioactive secondary metabolites such as antibiotics and toxins. The role of these secondary metabolites in the sick building syndrome is still largely unknown. In a previous screen a number of fungal and actinomycete isolates from problem houses were shown to have antibiotic properties against other microbes. Some of the isolates produced unidentified compounds reacting with DNA. Because of the role of DNA-damage in tumour induction these genotoxins might present a previously unknown risk associated with indoor air. In order to evaluate this risk it is necessary to identify the compounds in question, study their genotoxic potential, their production conditions and prevalence, volatility, stability, and possible other harmful effects. The aim of the project proposed in this application is to isolate and identify some of the most potent genotoxins produced by the representative microbial isolates from problem houses. The isolation is based on the fractionation of the culture media by standard procedures (organic solvent extraction, affinity chromatography, thin layer chromatography, HPLC etc.). The activity of the fractions is monitored by their selective toxicity to a DNA-repair-deficient bacterial strain extremely sensitive to DNA-damage.. A more thorough mutagenicity testing with both bacterial and mammmalian test systems is then applied to the purified fractions. Purified substances are characterized using mass spectrometry, other spectroscopic methods and NMR. When sufficient information of their chemical nature has been obtained this can be used as a basis of their detection in actual problem houses and for a tentative risk evaluation.
Keywords: Indoor air, mould, aktinomyketes, sekundary metabolic, genotoxisity, mutagenity
Graduate student:
Susanna Nieminen
The project examines the association between perceived insecurity and
uncertainty of people and environmental problems
(mould and asbestos) theoretically affecting health, creates with local
population research based model for decision-making
process to control the problem. The project first makes baseline measurements
on indoor air quality, asbestos in yards,
health profile of population and perceived insecurity and uncertainty
among the population as well as the awareness and
knowledge about the problem. Based on these results and analysis of
current decision making system the model for decision
making is created by researchers, decision makers and laypopulation.
The model is also tested.
Specific aims are:
-to determine microbiological quality of indoor air in public buildings
including schools and the health status of the users of
buildings,
- to measure asbestos of soil in the intimate surroundings of people
living in the asbestos polluted area (Tuusniemi),
- to compare health profile of population with the Finnish population,
- to assess insecurity due to and awareness of the environmental threats
in the area, and the knowledge about the problems
among the population, decision makers and municipality officers,
- to assess uncertainty about expertise among population and degree
of uncertainty among decision-makers and civil
servants about decision-making process,
- to create and test with researchers, decision-makers and laypeople
the model for decision making process based on the
analysis of the current decision making and the results of the measurements,
- to measure change in insecurity, uncertainty, awareness and knowledge
among the population, decision makers and the
officers of the municipality after evidence based information campaign.
Key words: mould, asbestos, health, perceived insecurity, uncertainty, decision-making
Consortium: Mould, health and houses
Research group:
Aulikki Nissinen, MD, PhD, prof.; Jussi Kauhanen, MD, PhD; Markku Myllykangas,
PhD; Pauli Niemelä, PhD, prof.; Juha
Kinnunen, PhD, prof.; Sirkka-Liisa Pamilo, MSc.; Aino Nevalainen, PhD,
dos.; Tuula Husman, MD, PhD.; Ulla Haverinen,
MSc: Mika Toivola, BSc, Jyrki Liesivuori, PhD
The municipalities Siilinjärvi and Tuusniemi collaborate in the study.
In the consortium the project has close collaboration with the projects
"Schools, mould and threat intervention study" and
"Development of methods to monitor the effectiveness of repairs". Project
also is linked with other research of the experts,
eg. insecurity research by Professor Niemelä.
Sites of the research:
University of Kuopio: Department of Public Health and General Practice,
Department of Social Sciences, Department of
Health Policy and Management
National Public Health Institute, Division of Environmental Health
Finnish Institute of Occupational Health, Kuopio Regional Institute
for Occupational Health
The study aims at combining the construction of a good radon-tight foundation and moisture prevention in new low rise residential houses. The study aims also at developing the applicability of different ventilation strategies, the control of depressure in dwellings and use of fresh air vents for reduction of indoor radon concentration. The study also deals with the radonsafe foundation construction of blocks of flats. Without any radon prevention the recommended limit for new houses, 200 Bq/m3 will be exceeded in 50 % of new houses in wide areas of the southern Finland.
The recommended radonsafe construction of a slab-on-grade foundation is based on the use aluminized bitumen felt which seals the foundation and prevents the leakage of radon-bearing soil air into living spaces. The construction provides also a qualified moisture prevention against moisture originating from the subsoil. Radon safe construction will be compared with the normal moisture prevention, using simulation calculations. In some houses the moisture of house constructions and subsoil will be measured.
The study will be carried out in 15 single family houses where the radon safe constructions will be controlled by experts of this project. Indoor radon concentration, air exchange rate, depressure and the operation of air exchange instrumentation will be measured carefully. This provides a basis for estimating the radon entry rate into the houses and the success in radon prevention.
The direct influx of radon-bearing soil air increases also the indoor radon concentration of flats of the lowest floor dwellings, in some cases also in upper floors. In this study the alternative radon foundation constructions of apartment houses will be surveyd, measurements will be made in 5 test houses. The depressure in flats has also a remarkable effect on indoor radon concentrations. The applicability of fresh air vents in flats for reduction of depressure, radon concentration and generally the indoor air quality will be studied in test houses and laboratory. The effect of commercially available fresh air vents on depressure and draft will be studied.
Keywords: radon, radon prevention, moisture damages, ventilation
Research place:
Facilities of Radiation and Nuclear Safety Authority and collaborators.
Co-operation:
Assoc. prof. Martti Viljanen Helsinki University of Technology, Laboratory
of Structural Engineering and Building Physics,
Prof. Olli Seppänen and researcher Jarek Kurnitski Helsinki University
of Technology, LVI-Laboratory,
Pekka Järvinen Katepal Oy.
Even though air handling systems are intended to improve indoor air quality and climate, they have often become major sources of odorous compounds. The filter has usually been the main cause of sensory pollution, and its emission has increased with time. Dirty ducts and coils have also remarkable odor emissions. Already the new ducts are often heavily contaminated with processing oil residues and with dirt accumulated during storage and construction period of the building. On the other hand, it has been found that the sum of the odors released from various components may not be in good agreement with the perceived emission from the whole system. Adsoption and desorption processes between accumulated particulate impurities and gaseous pollutants seem to play an important role for the final air quality. In addition, chemical reactions between oxidizing pollutants, such as ozone, and the organic pollutants adsobed on particles have been suggested to occur and to further deteriorate the air quality.
In this study, the adsorption and desorption properties of dust collected on filters and other parts of the air handling units are investigated. Especially, the significance of adsorption and desorption phenomena on air quality is considered. The data are also used to model the interactions between particulate matter and gaseous compounds. The chemical reactions will be studied. The ultimate aim is to prepare guidelines for cleaning and maintenance.
Dust samples will be collected from office buildings locating in downtown areas of Helsinki and Kuopio. For comparison, samples will also be collected from buildings in clean suburban area in Kuopio. The properties, such as spesific surface area, density, carbon content, and carbon/nitrogen-ratio, affecting the adsorption/desorption properties will be determined. Used air filters will be installed into a laboratory scale air handling unit for further studies. The gaseous compounds that will be investigated include the common volatile organic compounds belonging to aliphatic hydrocarbons, aldehydes, terpenes, and aromatic compounds. In addition to the physico-chemical properties, the odor emissions from the dust samples and the effects of ozone will be determined.
The non-allergic symptoms that are reported by people occupying moldy buildings are assumed to be caused by microbial metabolites and components, such as fungal b(1‹3)-D-glucans, even though the biological effects of these agents and their relationship with fungal antigens have not yet been clarified sufficiently. It is also possible that the reactions that are reported to be caused by fungal antigens might be mediated by mechanisms other than those of immediate type of allergy. In this context, it is interesting that the molecular structure of only few fungal allergens is known so far, and that the cross-reactivities between different fungal species have been weakly characterized. On the other hand, skin and serological tests are generally performed in the clinical work with unstandardized fungal extracts without the clear comprehension, how the results should be interpreted. The specific knowledge on the composition of fungal allergens would also be useful for the development of specific detection methods so that the most harmful fungi, e.g. Stachybotrys chartarum, could be easily identified in the environment.
This research project is divided into two parts. In Part 1, Characterization of allergenic components of some mold species and the development of a specific detection method for Stachybotrys chartarum, the antigenic compositions of four to six fungal species (S. chartarum, A. versicolor, P. brevi-compactum, C. cladosporioides, and two yeasts) the exposure to which is common in moldy buildings or agriculture, is characterized by SDS-PAGE and immunoblotting using immune and human sera. The cross-reactivities of the fungi between each other and with other common fungal species are investigated by the same method, and the specific components are determined. Polyclonal and/or monoclonal antibodies are created against these components. ELISA methods for measuring mold-specific antibodies and ELISA inhibition methods for measuring the antigenic components of these fungi are also developed. The important objective of the study is to produce the specific components of S. chartarum and possibly of some other fungus as recombinant proteins. For identifying these proteins, the cDNA library is created and the library is screened by specific antibodies. The gene coding for the specific component is transformed in the Pichia pastoris yeast for production. This approach allows the definition of the nucleotide and amino acid sequences as well as the production of the protein in great amounts and, thus, enables the development of a rapid detection method for the fungi, particularly for S. chartarum.
In Part 2, Exposure of mice by inhalation to fungi, irritating effects in the respiratory tract and immune responses, mice sensitized to the fungi mentioned above, are repeatedly exposed to various amounts of fungal antigens, glucans and volatile metabolites by inhalation, and the respiratory functions of mice are monitored continuously during the experiment. The irritating potencies of the agents are determined. After the exposure, the levels of specific antibodies (IgG, IgE, IgA) in serum and inflammatory mediators (IL-1, IL-6, TNF-a) in bronchoalveolar lavage fluid are measured. Histological analyses are performed from the tissue samples of the upper and lower airways. According to the results, the biological effects of fungal agents can be elucidated.
Key words: fungal allergens, fungal components, immune responses, inhalation exposure, irritation, recombinant proteins
Population exposure and to air pollution caused by different chemical
compounds and to annoying odours inside buildings is
usually much more significant than outdoors due to higher concentrations
and overall longer periods of time spent indoors.
As the indoor air quality (IAQ) has a non-negligible impact on human
health and comfort, a healthy indoor climate should be
one of the main objectives of today's construction practise. This,
however, requires development of comprehensive and
effective ways for characterisation of the air indoor and related symptoms.
Until now, only a few health effect studies
concerning the health and discomfort effects of indoor air have been
carried out. Indoor air is strongly affected by the
surrounding building materials releasing a wide variety of chemical
compounds such as volatile organic compounds (VOCs),
aldehydes and ammonia, which are suggested to cause several types of
health effects and discomfort. As only little
knowledge of material emissions and their health and acute discomfort
effects is currently available and as there is no
consensus on the harmful chemical compounds, source emission control
is currently considered the most effective control
option. Some classification systems, such as Finnish 'Classification
of Indoor Climate, Construction, and Finishing Materials'
are already been promoted. The development and use of new healthy materials
however requires deeper understanding of
material emissions and their correlation with perceived indoor air
quality, personal health and well being.
The first aim of this research is to establish the causal connection
between the diagnosed health effects and the chemical
composition of indoor air. Based on this knowledge, criteria for good
indoor air may be created. The second significant aim
is to generate more health and comfort related IAQ and material emission
evaluation procedures to be utilised in indoor air
diagnostics and material classification purposes. These aims can be
achieved by the following research tasks:
- simultaneous production of health effect and IAQ data
- understanding of causal connection of both indoor and outdoor emissions
and their impacts on personal health and
well-being through modelling and with the help of an extensive database
- development of comprehensive chemical measurement and sensory evaluation
techniques, complementary to currently used
ones, for IAQ and material emission control
- implementation of new testing procedures for indoor air and material
emissions
- prediction of IAQ from material emission data with the help of a
model, which takes into account also the physical
parameters, e.g. ventilation rate and sorption effects
The first task is aimed at establishing criteria for healthy indoor
air. This is obtained by combining the existing data from
VTT's IAQ-database, the indoor air data from EU-Expolis study and comprehensive
health related data, which is obtained
by choosing subjects among the patients treated in Helsinki University
Central Hospital because of building related
symptoms. The health and comprehensive indoor air data obtained from
the subjects and their homes are compared with
similar data of a control group. For collecting the comprehensive indoor
air data new methods are utilised in order to detect
very volatile (VVOCs) and semi-volatile organic compounds (SVOCs) and
polar compounds.
The aim of the second task is to develop procedures to evaluate the
irritating and odorous chemical compounds of material
emissions and the perceived air quality. The causative relationships
between sensory assessment method used in the present
Finnish Classification of Finishing Materials, olfactometry and emission
measurements in chemical terms are determined. The
irritate data is produced in a study "Irritating properties of emissions
from building materials" co-ordinated by
University of Kuopio. The data obtained in this study is combined with
data from VTT's DAME database in order to create
an evaluation method for the revision of the present Finnish Classification
for Finishing Materials.
The third task is focused on establishing a modelling procedure for
predicting IAQ based on material emission data. In order
to create an IAQ model, a procedure for testing sorption effects in
laboratory scale is established and material emission
together with sorption data is produced.
Key words: Indoor air, material emissions, VOCs, sensory evaluation, odors, irritation of material emissions, interdependence of irritate data and VOCs, odor and IAQ problems, modelling of IAQ
Organisation of the research:
VTT Chemical Technology: Kristina Saarela, M.Sc. (responsible project
leader). VTT is responsible for
IAQ-measurements, evaluation of material emissions by chemical and
sensory means and for modelling.
University of Kuopio (UKu): Pentti Kalliokoski, Ph.D, Anna-Liisa Pasanen,
Ph.D. UKu is responsible technical
performance of animal studies and for theoretical evaluation of irritancy.
Helsinki University Central Hospital (HUCH): Tari Haahtela, Doc., Helena
Mussalo-Rauhamaa, Doc. HUCH is responsible
for clini= cal examination of subjects and respective control subjects.
Postgraduate students:
M.Sc. (Tech.) Markus Tähtinen will prepare his doctoral thesis about IAQ modelling.
The aim of the research project is to work out calculation facilities for mould transfer through constructions and inside the buildings, and to produce solutions and basis for solving mould and moisture problems by using pressurisation and insulation techniques with particular regard to moisture and mould transfer and health aspects. The following tasks are included in the research. 1. To work out mould transfer models by which both the spreading of the metabolic products and the mould spores in the constructions and inside the building can be modelled. 2. To give guidelines and limits on how to use pressurisation and insulation as repairing measures for preventing mould transfer. 3. To analyse possible side effects, moisture behaviour of constructions and mould growth caused by changing pressure conditions and, respectively, to produce guidelines with regard to moisture behaviour and mould growth. 4. To develop a new serum IgG avidity test in order to estimate the exposure to moulds in cross-sectional and follow-up studies.
Theoretical models for estimating the risk of occurrence of mould growth, growing and spreading of the mould and models for the moisture transfer will worked out. Models for spreading of mould will consider both particles (mould spores) and gases (metabolic products). Moisture transfer models will include the modelling of moisture convection and diffusion, but not water contact. Conditions for mould growth and material properties effecting on mould growth that are initial parameters for the estimating the mould growth, are mostly taken from other studies and literature. Laboratory tests and field measurements (in single-family and apartment houses) are used for developing and validation of the models. All developed mould and moisture models can be simultaneously used with traditional heat transfer and air flow models in modular simulation environment IDA.
Health hazards caused by microbes and water damages are studied by measuring the exposure of residents in test houses with new clinical methods. In addition to measuring the exposure, the purpose of clinical methods used is to estimate the time period, when the exposure to mould allergens has occurred. The state of residents' health is studied with epidemiological examinations. The same medical examinations are made before and after repairing measures and also in "clean" houses.
The behaviour of repairing solutions, worked out in the research, will be shown with computer simulations by using developed models and with laboratory and field measurements. The effect of the overpressurising will be analysed by studying the drop of contaminant concentrations, caused by changed direction of air flows (leakage), and also the change in moisture behaviour, caused by possible moisture convection, will be studied. In addition to measuring moisture conditions, the behaviour of mould growth will be studied by laboratory measurements and computer calculations. The important properties of constructions that make it possible to use the pressurising will be given and construction solutions where pressurising cannot be used will be outlined by examples.
Key words: Moisture, mould, pressurising, insulation, health, dwellings
The research is carried out by
Helsinki University of Technology, HVAC-Laboratory
University of Kuopio, Department of Environmental Sciences
Helsinki University Central Hospital, Departments of Dermatology and
Allergic Diseases
Project manager:
Jarek Kurnitski, M.Sc. (Eng.), Helsinki University of Technology, HVAC-Laboratory, Tel: +358 9 451 3609, Fax: +358 9 451 3418, P.O.Box 4400, FIN-02015 HUT, Finland, E-mail: jarek@cc.hut.fi http://www.hut.fi/Units/HVAC/
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