Fungal Growth in Buildings: The Aerobiological Perspective

Harriet A. Burge Ph.D. Harvard School of Public Health, Boston, and questionably ethical scientist

NOTE; There were several typos and misspellings from the original manuscript that have been corrected for validity purposes on this site.

In the search for inexpensive shelter, we have developed indoor environments that are conducive to fungal contamination. While active fungal growth indoors is usually inappropriate and should be controlled, assessing specific health risks associated with such growth remains a challenge. Epidemiological tools are often used to determine relative risks associated with occupancy by groups of people in environments with or without certain factors, including fungal growth, but do not always make clear the role of the growth in the disease process in individuals. Aerobiologists assess relationships along a pathway that includes sources, dispersion and decay of aerosols, exposuree to individuals, doses of agents, and responses. Both approaches yield valuable information, but require the development of testable hypotheses.

As a model, we can apply the epidemiological and aerobiological processes to the Cleveland hemosiderosis outbreak, and consider the following hypotheses:

The Cleveland babies that develop hemosiderosis are more likely to live in moldy homes than those that did not develop the disease, all other things being equal.

The Cleveland babies that developed hemosiderosis are more likely to live in homes with Stachybotrys than those that did not develop the disease, all other things being equal.

Aerobiology Babies that developed disease were likely to have received a dose of Stachybotrys chartarum toxins sufficient to cause the reported symptoms.

Some evidence exists to support Hypothesis 1.

Hypothesis 2 is supported by very little evidence

Hypothesis 3 has not been tested.

Until Hypotheses 2 and 3 are adequately tested and verified, assuming a cause/effect relationship for Stachybotrys toxins in these cases is premature. Premature establishment of cause/effect relationships may lead to unnecessary concern, and prevent discovery of actual causes of disease. This hypothesis development and testing process is essential if we are to accurately determine the role of indoor fungi in human disease.


Why are there Still Problems with Fungal Allergen Extracts? 

W. Elliott Horner, Samuel B. Lehrer Air Quality Sciences, Inc., Atlanta, GA, and Tulane University Medical Center, New Orleans, LA email

It has long been axiomatic that reliable allergen extracts of fungi are more difficult to produce and work with than extracts of pollen, dander, or other allergen sources (Salvaggio, 1981; Burge, 1985; D’Amato, Spieksma, 1995; Feinberg, 1946). Features of fungi that contribute to this include their number and variety, the identification is sometimes difficult, their phenotypic plasticity, and the presence of endogenous proteases that can degrade allergens in crude extracts. All of these problems can be addressed to an extent, albeit some with difficulty. Indeed, with the few fungi with which molecular techniques are being used, recombinant allergens are readily being produced. Unfortunately, adequate resources and resolve are lacking for a concerted effort at producing well-characterized allergen extracts. Further, the extracts that are available correspond poorly with the fungi that are often a problem indoors.


Comparative studies of fungal media for the recovery of Stachybotrys Chartarum from Environmental Samples

Stella M. Tsai1, M.Sc., Chin S. Yang, Ph.D., Patricia Heinsohn, Ph.D., CIH P&K Microbiology Services, Inc., Cherry Hill, NJ

Five commonly used fungal media were used to determine the relative recovery efficiencies of Stachybotrys chartarum (SC) by culturing sixty-five unknown environmental samples from building materials. These fungal media were cornmeal agar (CMA), Czapek cellulose agar (CCA), 2% malt extract agar (2% MEA), 1% malt extract agar (1% MEA) and rose bengal agar (RBA). The samples were first examined microscopically for the presence of SC. It was found that all five fungal media were all suitable for the recovery of SC from the environmental samples. The recovery frequency of SC from bulk samples ranged from 87.7% on 2% MEA to 95.4% on CMA. Qualitative differences of colony growth and interaction between S. chartarum and other fungi were observed on the media. CMA yielded the best sporulation and highest recovery rate of SC from the environmental samples. The other four media also supported the isolation and recovery of SC but at reduced rates.


Heteroduplex DNA Fingerprinting of Penicillium Brevicompactum from House Dust

James A. Scott, Neil A. Straus1, Bess Wong Department of Botany, University of Toronto E-mail:

It is widely believed that many osmotolerant microfungi, including toxigenic species of Aspergillus and Penicillium proliferate on indoor substrata such as dust and broadloom even in the absence of appreciable moisture. This hypothesis has been offered as an explanation for the disproportionate abundance of propagules of these species in indoor environments, relative to their representation in outdoor reservoirs such as air and soil.

We obtained several thousand isolates of Penicillium from 367 homes in southwestern Ontario, Canada. From these, 75 isolates of P. brevicompactum representing 54 houses were selected based on micromorphological and physiological uniformity. Sequences of PCR-amplification products of polymorphic genetic loci were compared between isolates using heteroduplex mobility assay (HMA), demonstrating two primary, genetically divergent groups which appear to be stable, clonally-reproduced lineages within the dust mycoflora. These clones are distributed throughout the sample population and co-exist at several sites, suggesting that in absence of objective moisture problems, the principal amplifiers of P. brevicompactum lie outside the building environment. It is possible that mechanical / filtration effects (e.g. differential removal of propagules by vacuum cleaning and elutriation in air conveyance systems), and the relatively long spore viabilities of trichocomaceous anamorphs play a significant role in concentrating propagules of these microfungi in homes.


The Trichodiene Synthase Gene from Stachybotrys Chartarum : A Potential Diagnostic Indicator of Indoor Contamination

Neil A. Straus PhD, James Scott, Bess Wong MSc Department of Botany, University of Toronto, Canada Email:

The hyphomycete Stachybotrys chartarum readily grows on damp cellulosic areas in buildings producing spores that may contain highly toxic trichothecenes. Here we report the cloning, sequencing of the gene for trichodiene synthase which is the first enzyme of the pathway uniquely dedicated to the synthesis of trichothecenes. The predicted amino acid sequence shows regions of high conservation. Nucleotide sequence divergence permits the selection of PCR primers that can detect the trichodiene synthase gene of S. chartarum in DNA diagnostic strategies.


Microscopic Fungi and Metabolites in Dwellings-a Bioassay Study

Ing. Elena Piecková, M.P.H., Ph.D., MUDr. Zdenka Jesenská, Dr., Sc., Ken Wilikins, Ph.D. Institute of Preventive and Clinical Medicine, Bratislava, Slovakia

The ciliostatic effect of chloroform-extractable endo- and exocellular metabolites of the most frequently isolated fungal strains from growth in dwellings: Alternaria sp., Aspergillus glaucus group, A. versicolor, Cladosporium sphaerospermum, Penicillium sp., P. chrysogenum, Stachybotrys chartarum, Trichoderma viride and Ulocladium sp. was studied on tracheal cilia from day old chicks in vitro. Biomass extracts from Alternaria sp. and A. versicolor as well as exocellular extracts from P. chrysogenum, S. chartarum I, T. viride and Ulocladium sp. stopped cilia movement during the first 24 hours. Biomass extracts of P. chrysogenum, S. chartarum I and T. viride as well as media extracts from Alternaria sp., C. sphaerospermum and Penicillium sp. stopped cilia movement between 24 and 48 hours. Between 48 and 72 hours the biomass extract of an A. glaucus gr. isolate and media extracts of A. versicolor and S. chartarum II showed activity while the other extracts (cellular from C. sphaerospermum, S. chartarum II and Ulocladium sp. and media one from A. glaucus gr.) showed no activity. The results are discussed in relationship with health status of people living/working in moldy buildings.


Moisture, Mold and Health in Apartment Homes

A. Nevalainen, Ph.D., M. Vahteristo, M.Sc., J. Koivisto, Civ.Eng., T. Meklin, M.Sc., A. Hyvärinen, M.Sc., J. Keski-Karhu, M.Sc., T. Husman, M.D. National Public Health Institute, Division of Environmental Health e-mail

The prevalence of observations of moisture or mold, and the respiratory health status of the occupants, was surveyed in a random sample of 120 apartment buildings. The buildings and two apartments from each were given a walk-through inspection and all the signs of moisture and mold recorded using questionnaires and checking lists by civil engineers. A health questionnaire was sent to the occupants. In 60% of the apartments, signs of moisture damage could be observed, and 42% of the apartments were assessed to be in need of repair because of the moisture observations. Respiratory symptoms, such as cough, nocturnal cough and dyspnea, sore throat, hoarseness, rhinitis, nasal bleeding and impaired sense of smell were significantly associated with the observations of moisture, as well as sinusitis (OR=2.58). When the exposure was defined as mold present the symptom findings were almost similar. The results show the health-based importance of good maintenance.


Toxigenic Microbes in Indoor Environment: Identification, Structure and Biological Effects of the Aerosolizing Toxins

Salkinoja-Salonen M.S., Ph.D., Andersson M.A., M.Sc, Mikkola R., M.Sc, Paananen A.,B.Sc, Peltola J., M. Agr. & For., Mussalo-Rauhamaa M.D.,Ph.D., Saris N Ph.D., Grigorjev Ph.D, Helin Ph.D., Koljalg, Ph.D, Timonen M.D.,Email:

Almost 500 pure cultures, bacteria and fungi, were isolated and identified to genus or species level from indoor environments where the occupants were suffering health problems. Over 80 different taxa were identified. Seven bacterial species classified to Hazard Group 2 were found. Extracts prepared from the building materials and from the pure cultures, were tested for their effects on cellular energy production and conservation using boar spermatozoon and human NK cells as test cells. Strains giving toxic responses were found among strains from 11 taxa. Cell free extracts prepared from cultures of Bacillus cereus, Bacillus licheniformis, Streptomyces griseus, a new species of Nocardiopsis, Stachybotrys chartarum and Trichoderma sp were shown to contain toxins that depleted the spermatozoon of ATP and destroyed plasma membrane integrity. Strains of Streptomyces griseus and Bacillus cereus were shown to produce toxins that caused mitochondrial swelling and programmed NK-cells towards apoptosis. These toxins were dodecadepsipeptides and operated as K+ ionophores across the mitochondrial membrane. Strains of Bacillus licheniformis and Trichoderma produced toxins that depleted the spermatozoon of ATP. The toxins were nonenzymatic, highly hydrophobic, robust molecules of small size (<104 g mol-1), effective at low concentration (ppb). We propose that the building related health symptoms of the occupants exposed to one or several of the taxa indicated above, may be caused by microbially emitted toxins. We discuss possible mechanisms of human toxicity.


Evaluation of Exposure to Environmental Bacteria

Laitinen Sirpa, Ph.D., Kangas Juhani, Ph.D. Kuopio Regional Institute of Occupational Health, Finland

The present study provides information about the methods used to determine airborne bacteria in occupational environments. The best means proved to be the analysis of filter samples with endotoxin and peptidoglycan assays. The results of the assay, which measures the biological activity of cell wall components, mainly endotoxins, correlated well with the measured concentrations of viable airborne bacteria, especially with the levels of gram-negative bacteria. The endotoxin analyzed by chemical markers did not correlate well with the results of the assay nor with the viable bacteria levels, despite the similarity between the bacterial species identified from the culture media and the corresponding 3-OH fatty acids analyzed by the GC-MS assay. Indicative information on total bacteria levels could be obtained from peptidoglycans, which correlated well with total viable bacteria.


Cellular and Humoral Responses in an Animal Model Inhaling Penicillium Chrysogenum Spores

J. Danny Cooley, Ph.d., Wing C. Wong, M.S., Cynthia A Jumper, M.D., David C. Straus, Ph.D. Departments of Microbiology and Immunology1 and Medicine at Texas Tech University Health Sciences Center, Lubbock, Texas

Penicillium chrysogenum (Pc) is a potential causative agent of the complaints and symptoms of occupants in buildings experiencing "sick building syndrome". Viable Pc spores were recovered from the lungs of mice 15 minutes and 3 hours through 36 hours after intranasal (IN) inoculation of 1x106 spores, of which 25% were viable. Eighteen percent of the viable spores were deposited in the lungs, however, by 12 h, only 1x104 viable spores were recovered. This suggests that the mucociliary tract had cleared the majority of spores deposited, but four percent (1x104) of the viable spores were retained in the airways and were probably deposited in the alveolar spaces and remained viable for up to 36 h post-inoculation. Similar acute doses of viable spores induced significant (P<0.001) increases in tumor necrosis factor a (TNF-a), while non-viable (NV) Pc spores did not. Repeated doses (3 weeks) of 1x104 viable spores induced significant (P<0.05) increases in total serum IgE and bronchioalveolar lavage (BAL) interleukin-4 (IL-4), whereas 1x104 NV spores did not. This suggests that viable Pc spores are capable of inducing allergic responses.


Sporulation of the Hyphomycete Stachybotrys chartarum Under Three Light Conditions

Patricia Heinsohn1, Ph.D., C.I.H., Sharon Harney, Ph.D., K. Alexandros Exuzides, Ph.D. Menlo Park, CA

Stachybotrys chartarum is a widespread hyphomycete commonly isolated from a variety of substrates including soil and wood. It can be found growing in building materials, which have become wet before or after construction. The inhalation of S. chartarum conidia can cause pneumomycotoxicoses, and a recent study linked S. chartarum to the deaths of infants diagnosed with pulmonary hemosiderosis in Cleveland. While S. chartarum is frequently isolated, the conditions under which it sporulates are unknown and are important issues in assessing indoor air quality. This study reports on the sporulation of S. chartarum under three different artificial light conditions. Two isolates of S. chartarum were inoculated onto two different media, MEA and CMA, and exposed to either 24 hour dark, a light/dark cycle, or 24 hour light. After growth initiation, growth rate and degree of sporulation were measured. Results indicate that growth rate and degree of sporulation differ with light conditions and media. On CMA the initial growth rate under 24 hour light was higher than under light/dark and 24 hour dark. Light/dark conditions were more conducive to early sporulation whereas 24 hour dark delayed sporulation. Sporulation did not occur under any light condition on MEA for six days. The data indicate that under favorable growth conditions, S. chartarum can sporulate under any light condition. Therefore, S. chartarum growing in buildings in dark areas can sporulate for dissemination into the air.


Mycotoxin Spectra as a Biochemical Parameter for Occupational and Environmental Fungus Exposure

M. Müller, Ph.D., J. Bünger, M.D., E. Hallier, M.D., Prof. Center of Environmental and Occupational Medicine, Department of Occupational and Social Medicine, Georg-August-University e-mail:

Mycotoxins are metabolites formed by molds in foodstuffs, fodder and organic waste materials. All molds produce specific mycotoxins and species can be characterized by their mycotoxin spectra. We have established a method for mycotoxin extraction from defined cultures. HPLC separation with diode array detection or iontrap mass spectro-metry and comparison to an authentic standards library was used to screen seven Aspergillus and Penicillium species collected at waste treatment plants for their major mycotoxins. The human hepatocarcinogen sterigmatocystin was detected in Aspergillus versicolor and Aspergillus nidulans. Verruculogen, a potent tremorgen, and fumagillin, formerly used as a cytostatic drug, are mycotoxins found in Aspergillus fumigatus. Penicillium crustosum and Penicillium brevicompactum each produced the tremorgens roquefortine C and penitrem A. The mycotoxin standards library can be used to identify specific mold species in ambient air samples from environmental and occupational investigations.


Membrane Toxic Substances in Water-damaged Construction Materials and Fungal Pure Cultures

University of Helsinki, Department of Applied Chemistry and Microbiology, Division of Microbiology,University of Helsinki, Finland Email:

We showed toxic substances in and isolated toxin producing microbes from water-damaged building materials. The toxins were extracted from the building materials and microbial cultures in methanol and analysed using boar spermatozoa as test cells. The fungal genera isolated from the toxic materials were identified as representatives of Stachybotrys chartarum, Aspergillus, Alternaria, and Penicillium. We found that toxin from the building materials and from four fungal isolates paralysed sperm cell motility and damaged cell membrane at low concentrations (EC50 < 10 mg of methanol soluble solids ml-1 of extended boar semen). The toxic isolates were identified to Stachybotrys chartarum. The toxin from one Stachybotrys chartarum strain was partially purified. To our knowledge, this is the first demonstration of membrane damaging toxin and their producer fungi from the building material.


Different Methods to Characterize Moldy Buildings

Toivola Mika, B.Sc., Reiman Marjut, Ph.D.; Hyvärinen Anne, M.Sc.; Meklin Teija, M.Sc.; Nevalainen Aino, Ph.D. National Public Health Institute of Finland, Division of Environmental Health, Laboratory of Environmental Microbiology e-mail:

Different methods were evaluated for their potential to show unusual microbial conditions in a building. The buildings studied were schools and offices. The buildings were inspected for visible signs of moisture by a civil engineer. Samples were taken from the air, surfaces and structures. Indoor air concentrations of viable microbes were higher in moldy than reference buildings. This difference could not be seen in the total counts of biological particles. In most cases, the concentrations of microbes on the surfaces were low. In some cases microbial concentrations were high in material samples although no contamination could be seen in surface swab samples from the same damage area. With one sample or one method alone, the conclusion of the mold problem in the building could not necessarily be drawn.


Comparative Studies of Collection Efficiency of Airborne Fungal using Andersen Single-Stage Sampler and Air-O-Cell Cassettes

Stella M. Tsai1, M.Sc., Chin S. Yang, Ph.D., Patrick Moffett, Andrew Puccetti, Ph.D., C.I.H. P&K Microbiology Services, Inc., Cherry Hill, NJ

The collection efficiency of airborne fungal matter using the Andersen single-stage sampler and Zefon Air-O-Cell cassettes was compared in this study. A total of 814 sets of samples were collected. The correlation coefficient (r) between these two methods was at 0.33 (p < 0.05) for total fungal matter and at 0.29 (p < 0.05) for Cladosporium. The correlation coefficient (r) between the total fungal and Cladosporium concentrations collected from Andersen air samples and Air-O-Cell cassettes was at 0.78 (p < 0.05) and 0.62 (p < 0.05), respectively. Stachybotrys-like spores were detected in 74 Air-O-Cell samples. Stachybotrys chartarum was detected in 5 Andersen samples. Four sets of samples showed Stachybotrys chartarum on both Air-O-Cell and Andersen air samples.


Trichothecene Mycotoxins in Some Water-Damaged Buildings

Tapani Tuomi1 Ph.D., Lauri Saarinen M.Sc., Sanna Lappalainen Lic. Phil., Outi Lindroos M.Sc., Marjo Nikulin Ph.D., Kari Reijula M.D., Ph.D. Finnish Institute of Occupational Health, Uusimaa Regional Institute, Helsinki, Finland, e-mail

Bulk samples of moldy interior finishes, settled dust, contact inoculated microbiological samples (mixed cultures), as well as pure cultures isolated from indoor environments, were subjected to the qualitative and semi-quantitative simultaneous analysis of 12 trichothecenes. The analysis method was developed as a result of the present study and it includes extraction, sample pre-treatment and reverse-phase HPLC-separation with following tandem mass spectrometric identification and quantitation using electrospray ionization on a quadrupole ion trap mass analyzer.

Similarly to previous studies on fodder or foods, contaminated with trichothecene producing moulds, diacetoxyscirpenol and T-2 toxin were the most prevalent trichothecenes. Apart from these, 3-acetyl-deoxynivalenol, T-2 tetraol, verrucarol and roridin A were occasionally present, particularly in samples contaminated with Fusaria or Stachybotrys spp. Satratoxins G and H were also found on rare occasions, especially from sites with a severe occurrence of Stachybotrys spp. All examined sites were Finnish water-damaged buildings, with confirmed health implications, resulting from fungal propagation.


Immunochemical Detection of Mycotoxins Associated with Stachybotryotoxicosis

R. Dietrich, Ph.D., E. Johanning, M.D., M.Sc., M. Gareis, D.V.M., Ph.D., Prof., E. Schneider, Ph.D., E. Usleber, Ph.D., E. Märtlbauer, Ph.D., Prof. Institute for Hygiene and Technology of Food of Animal Origin, University of Munich, Munich, Germany e-mail:

Using high-affinity monoclonal antibodies (Mab) against roridin A which exhibit cross-reactions with satratoxins and other macrocyclic trichothecenes several immunochemical methods were developed for the direct detection of satratoxins in contaminated building materials. Applying a lab-independent enzyme-linked immunofiltration assay (ELIFA) technique positive results were obtained within 10 min for toxin concentrations of > 200 mg/kg. The detection limit of a microtiter plate assay format was 1 mg/kg. For samples contaminated with Stachybotrys chartarum, an excellent agreement could be observed between the enzyme immunoassay (EIA) and a cytotoxicity test. The results of the EIA could be confirmed by HPLC analyses using immunoaffinity columns for sample clean-up. Furthermore, a new method was established for the sensitive detection of verrucarol in serum. In three out of 58 serum samples traces of verrucarol were detected. Two other sera reacted strongly positive for macrocyclic trichothecenes. Altogether, these results underline the importance and usefulness of immunochemical methods for epidemiological studies on airborne mycotoxins in indoor environments.


Mitigation of Visible Fungal Contamination in Buildings: Experience From 1993 - 1998

Philip r. Morey, P.H.d., Daryl Sawyer, B.s. AQS Services, Inc,. 2235 Baltimore Pike, Gettysburg, PA

Experience in the early 1990’s led to the recommendation that removal of visible fungal growth from interior surfaces in buildings be performed in a manner that minimized the dispersion of particles (dusts) in indoor air. Several documents beginning with the 1994 New York City Guidelines on Assessment and Remediation of Stachybotrys atra in Indoor Environments provided practitioners with procedures that can be used to remove visible fungal growth from building interiors. All fungal remediation guidelines recommend that sustained and extensive fungal growth on interior surfaces should be physically removed and that people performing remediation work should use appropriate personal protective equipment. In addition, all guidelines published in 1993-1998 recommend that moisture problems in building infrastructure be fixed in order to prevent new fungal growth. Fungal remediation guidelines specify a certain surface area of visible fungal growth (generally 3 to 10m2) that requires containment barriers similar to those used when hazardous chemical or physical materials are removed from buildings. Misunderstanding of 1993-1998 guidelines has resulted in both overly conservative approaches to clean-up as well as to dispersion of fungal spores throughout a building because of poor dust control. Unlike guidelines on removal of hazardous chemical and physical agents where rigid inspection protocols and specific numerical guidelines are appropriate, the removal of mycobiota is a variable process depending on many factors including the biology of the fungal taxa. Factors such as the following should be considered during the remediation process: (a) the location, extent, and kind of fungal growth in building systems, (b) the susceptibility of building materials to biodeterioration, (c) the porosity of building materials, (d) the susceptibility of occupants to bioaerosol exposure, and (e) sampling and monitoring protocols appropriate for the fungal contaminants. Fungal remediation in buildings continues to require a considerable degree of professional judgement with regard to procedures appropriate for containment of dusts and for control of the contaminant mycobiota.


Microbes and Moisture Content of Materials from Damaged Building

Meklin T., M.Sc., Haatainen S., B.Sc, Kauriinvaha E. M.Sc, Kettunen A-V. M.Sc, Haverinen U., M.Sc., Vahteristo M. M.Sc., Viljanen M. Prof., Nevalainen A Ph.D. National Public Health Institute, Kuopio, Finland, e-mail

The aim of the study was to characterize the microbial flora of the envelope of a school building and the correlation of the microbial concentrations and the moisture content of materials was estimated. Material samples (n=95) were taken from different structures before the dismantling of the school. In all, 40 sample pairs were taken from which both concentrations of microbes and moisture contents (% by weight) were determined. The range of the total concentration of fungi was <45 - 8 600 000 cfu/g for all the analyzed material samples. The growth of microbes in a building is mostly regulated by the moisture of the materials and often the elevated concentrations of mesophilic fungi (>10 000 cfu/g) were associated with elevated moisture content of the material. However, the microbial concentrations did not fully correlate with the moisture contents of the material.


Concentrations of Viable Spores of Fungi and Actinomycetes in Ventilation Channels

Outi Lindroos, M.Sc., Sanna Lappalainen, Phil.Lic., Kari Reijula, M.D, Ph.D. Uusimaa Regional Institute of Occupational Health, Indoor Air & Environment Program, Finnish Institute of Occupational Health, Helsinki, Finland, E-mail:

In this work we studied if accumulation of fungal spores to the ventilation channels has any significance as microbial source in indoor air. Concentrations of viable spores were determined from samples that were collected from ventilation channels, and the geometric mean and median values were calculated. The concentrations of fungal spores and actinomycetes on ventilation channel surfaces were low even in abundantly dusty channels, and therefore accumulation of spores in the channels did not seem to form any significant microbial source in indoor air. In the samples from exhaust channels in buildings with verified mold damages, prevalence of fungal species such as Acremonium sp., Aspergillus versicolor, Chaetomium sp., Eurotium herbariorum, Paecilomyces variotii, Phoma sp., Trichoderma viride and Ulocladium sp. was better indicator for damages than the concentrations of fungal spores.


Air Quality Restoration in a Fungal Contaminated Building

Herman Sabath M.P.H., Ph.D. International Environmental Diagnostics, Inc., New York 

Attempts to mitigate microbial contamination of a four story office building by use of common standard cleaning procedures proved inefficient by post abatement analytical results. Toxigenic, allergenic and pathogenic fungi were identified in sampling evaluation as a follow up to microbial abatement. Microorganisms such as Stachybotrys, Aspergillus, Penicillium, Cladosporium and Fusarium were detected in air and surface samples of a four story office building. Review of the chain of events revealed that microbial recolonization, cross-contamination and recontamination had occurred at this facility.

IED, Inc. an environmental company specializing in microbial abatement and air quality restoration in indoor environments was commissioned to the project of biocidal clean-up and air quality restoration. Success of such projects are strictly dependent on applied scientific knowledge and experience. IED, Inc. successfully completed the biocidal and air quality restoration project as proven by post abatement analytical results performed by an independent third party monitoring company and laboratories.


Sampling, Results & Remediation in 300 "Sick Houses"

Jeffrey C. May, email:

Inhabitants in "sick house syndrome" (SHS) homes suffer from allergy, asthma, sinus and other respiratory problems, including hypersensitivity pneumonitis and aspergillosis. Reports from 300 SHS homes were compared to randomly-selected reports from 150 homes inspected as part of pre-purchase agreements in the Boston area. SHS homes were almost twice as likely as other homes to have forced hot air heat, central air conditioning and finished/carpeted basements. Elevatedlevels of mold were found in 74% of SHS homes. The largest sources of bioaerosol were found to be carpeting; heating, ventilation, and air conditioning (HVAC) equipment; and beds and sofas. Respirable "carpet dander" from damaged wool carpet fibers can be an irritant. Effective SHS remediation may include: carpet removal; thorough coil /duct/blower cleaning along with replacement of contaminated fiberglass lining materials in HVAC equipment, and cleaning fleecy items with dry (super-heated) steam. Mite-barrier mattress and pillow covers are always recommended. SHS may be a cause for increased asthma rates.


Identifying and Preventing Fungal Contamination Problems in New Home Construction

Päivi Salo, M.Sc. University of North Carolina at Chapel Hill, School of Public Health, Department of Environmental Sciences & Engineering,

The objectives of this study were to identify construction materials and practices prone to introduce fungal contamination into new single family homes, and to identify preventive maintenance procedures which limit fungal colonization and amplification. This study was performed over a two year period in North Carolina. Eight construction sites were observed during construction and during the first year of occupancy.

Building materials were improperly stored and exposed to rain and/or high humidity. Inadequate drainage caused many crawl spaces to remain damp. Many HVAC systems were inadequately sealed, enabling rainwater and construction debris to enter the systems, and thereby providing suitable fungal substrates. Negative pressure within the building envelopes caused air infiltration from the crawlspaces. Many of the observed problems found could be avoided by educating builders and homeowners. Early identification and prevention of potential fungal reservoirs and amplification sites is preferable to costly analysis and repairs afterwards.


A Toxic Mold Cleanup Guide

Jim H. White, B.A.Sc., P.E.O. CMHC National Office, Ottawa, Canada

Many houses and small buildings are moldy, and some have extensive growth of toxigenic molds that can cause health problems at lower exposures than the phyloplane molds that are more common outdoors. Canada Mortgage and Housing Corporation, the Canadian federal housing agency, has performed a great deal of research into moldy houses and has created a number of publications on mold avoidance and cleanup. This document is one of a new series that addresses toxic mold cleanup as well as solving moisture problems and avoiding mold growth in the first place.


Molds as an Environmental Factor in Infant Leukemia?

Casteleyn L, Van Damme K, Van den Berghe H. Center for Human Gentics, University of Leuven, Leuven, Belgium

The possible influence of occupational, environmental and lifestyle exposures of parents on the occurrence of infant leukemia is studied. Infant leukemia diagnosed within the first 6 months of life occurs at a frequency of around 1 case in 50.000 live births and shows a consistent genomic defect involving the 11q23 band (the MLL gene). These rearrangements are considered to offer circumstantial evidence for an environmental factor being involved and compelling evidence exists that the particular mutation is acquired in utero.


Mechanisms of Adverse Health Effects of Moldy House Microbes: in vitro and in vivo studies on toxic effects and inflammatory responses.

Maija-Riitta Hirvonen, Ph.D., docent, National Public Health Institute, Division of Environmental Health, Kuopio, Finland, e-mail:

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.


Exposure to Bioaerosols

Principal investigator: Aino Nevalainen, docent, Ph.D. National Public Helath Institute, Laboratory of Environmental Microbiology, e-mail

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:

1. To study whether the exposure to viable microorganisms, total number of biological particles and fine particles of the individuals with mouldy house symptoms differ from the exposures of matched control individuals with no such symptoms

2. To study whether the same inflammatory mediators which are detected in the nasal lavage fluid of exposed individuals, can also be detected in vitro in the cell culture medium of macrophages after the exposure to particles, collected during the exposure period.

3. To study the within person and between persons variation of exposure to bioaerosols using repeated measurements.

4. To compare results of personal exposure and stationary sampling measurements in home and work.

A group of 35 individuals with symptoms typical to mould exposure will be selected and a control individual with no such symptoms will be selected for each index person. A 24-hour sample collection for bioaerosol and fine particles will be made with personal and stationary sampling in homes and in the working places. The homes and working places will be surveyed for signs of moisture damage according to a check list. During the sampling period, diaries on time activity in different microenvironments and on symptoms will be filled and PEF will be recorded. A nasal lavage fluid sample will be taken from each individual after the sampling period. This sampling period will be repeated twice with each individual.

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.


Schools, Mould and Health - An Intervention Study

Principal investigator: Aino Nevalainen, docent, Ph.D. National Public Helath Institute, Laboratory of Environmental Microbiology, e-mail

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:

1. To find out if there is a dose-response effect depending on whether an individual is exposed to mold in school or home or in both,

2. To find out whether the elimination of microbial growth and repair of moisture damage will eliminate the increase of respiratory symptoms and infections among the school students,

3. To find the most relevant methods to characterize the exposure associated with building moisture and mould, and

4. To develop a method to monitor the toxicity and biological activity of the indoor air particulate material.

Microbial exposure is characterized with microbial samples from the indoor air (impactor and filter), surface swab samples, house dust and pieces of damaged materials. Ergosterol concentration and lipid fatty acid profile by GC; acute cell toxicity and other biological activity, see the project of Dr. Hirvonen; concentrations of dog and cat allergens and house dust mites from house dust. The buildings will be inspected for their signs of moisture according to a chekc list and the repair measures will be documented. Health status of the children will be monitored with questionnaires which will be validated with absence analysis and symptom diaries.

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

for assessing the effectiveness of the repairs in decreasing the symptoms

for understanding which types of damage/exposure produce the highest risk to health

for monitoring the indoor exposure to biological contaminants

for monitoring the indoor air exposure to biological contaminants

for assessing the urgency ranking of the repairs, needed in the community planning


Development of Methods to Monitor the Success of Repair Measures

National Public Health Institute, Division of Environmental Health,

Laboratory of Environmental Microbiology, e-mail:

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.


Neurotoxic Effects of Microbial Toxins

Principal investigator: Prof. Kai Savolainen, MD, PhD, Finnish Institute of Occupational Health, Industrial Hygiene and Toxicology, e-mail:

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.


The Biological Activities of the Metabolites of Microbes Present in the Indoor Air

Principal investigator: Prof. Atte von Wright, Ph.D., Department of Biochemistry and Biotechnology, University of Kuopio, e-mail:

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.


Environment, Decision-Making and Well-Being - Insecurity, Uncertainty and Crisis of Expertise

Principal investigator: Prof. Aulikki Nissinen, University of Kuopio, Department of Public Health and General Practice, email:

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.


Radonsafe Foundation, Moisture Prevention and Air Exchange in a Healthy Building

Principal investigator: Hannu Arvela, Head of laboratory, Radiation and Nuclear Safety Authority, e-mail:

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.


Adsorption, Desorption, and Chemical Reactions in the Particulate Matter Collected on Air Filters and Ducts

Principal investigator: Prof. Pentti Kalliokoski, Department of Environmental Sciences, University of Kuopio, e-mail:

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.


Fungal Allergens and Antigens - Their Characterization and Biological Effects in Mice after Inhalation Exposure

Principal Investigator: Anna-Liisa Pasanen, PhD, docent, University of Kuopio, Department of Environmental Sciences, -mail:

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.


Indoor Air Quality Control

Principal investigator: Kristina Saarela, M.Sc.,VTT Chemical Technology, Environmental Technology, E-mail:

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 studiesconcerning 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.


Mold and Moisture Transfer in Building Structures and Buildings with Particular Regard to the Prevention of Health Hazards

Principal investigator: Prof. Olli Seppänen, Helsinki University of Technology, HVAC-Laboratory, E-mail:


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.