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How Alternative and Low-Energy Building Techniques Affect Indoor Microorganism Communities

Gwynne Mhuireach Maxwell Moriyama

University of Oregon Graduate Research Forum 2012

Biology in the Built Environment Energy Studies in Buildings Lab

Abstract: While humans spend 90% of their lives inside buildings, researchers at the interface of architecture and biology are just beginning to discover how and why indoor bacterial and fungal communities are affected by building design. In parallel, alternative and lowenergy building techniques such as rammed-earth and straw-bale, are becoming more popular as designers become cognizant of the energy and resource use required for conventional buildings. These two threads of thought converge in our preliminary study investigating the different microbial communities associated with conventional versus alternative building materials. Given the large differences between the microbial communities of soil and those of conventional buildings, as well as the potential health effects of the different community types, we propose a comparative microbiological evaluation of alternative built environments.

Why Focus on Alternative Building Materials? Sustainability:

Acknowledgments: Brennan Bohannan G. Z. Brown Jessica Green

Ceiling damaged by Penicillium fungi in the Fig. 8. Ceiling by Penicillium fungi inx1500. the Economic and Economic anddamaged Commercial Centre of Poland, Commercial Centre of Poland, �1500.

Why Study Microorganisms in Buildings?

Fig. 9. Microorganisms from fragments of decaying walls of Verkiai Palace, �3000.

Human Health:

Rammed Earth:

Temperature: Organisms involved in damages and defects of building components. — Viitanen., 2003

• High insulative properties ˇ ius Lugauskas and Jaskelevic • Susceptible to mold growth • Rapidly renewable resource

• High hygric mass

Downloaded from at UNIV OF OREGON on November 18, 2010

• Occupants • Modes of Dispersal

Characteristics of Surfaces: Prevalence of different fungal genera in damaged building materials. — Hyvarinen et al.

Relative Humidity: Optimum relative humidity range for minimizing adverse health effects. — Arundel et al., 1986

Support for Hypothesis:

Proposed Study Design:

Airborne bacterial communities differ significantly between indoor and outdoor environments. In this study, the relative abundance of humanassociated bacteria and potentially pathogenic bacteria was higher indoors. Sunday Monday — Saturday

Influences of environmental conditions on microbial diversity. — Kembel et al., 2012

Straw Bale:

• High thermal mass Indoor Built Environ 2007;16:358–370

Building Design and Microoganisms: • Daylight • Wind • Ventilation Air

Study of an Old Reconstructed Building used for Various Purposes in Savicˇius Str. The building is close to narrow streets; one of these is characterised by heavy traffic with its consequence of dust and simultaneously propagules of various microorganisms constantly being dispersed. The house is surrounded by other buildings so its natural ventilation and drying conditions are bad. The nearby buildings are damaged by micro-organisms including algae, some of them are under reconstruction, others decay awaiting reconstruction. So the outside mycological environment of the building is very unfavourable. The house is built of bricks; the walls are damp. The brick walls are decaying and this chemical process is driven by communities of micro-organisms formed of bacteria, yeasts, and micromycetes developing in the stonework. The dampness and

• Throughout human history, we have generally had a close association with soils and the microorganisms that inhabit them • Children raised in less sanitary conditions, like farms, have lower incidence of autoimmune disorders, such as asthma, allergies and COPD (i.e. Hygiene Hypothesis)


• Temperature • Relative Humidity • Surfaces

The premises with higher organic pollution levels were contaminated with Aspergillus (Figure 10) Absidia, Mucor, Thamnidium, Acremonium, Botrytis and other micromycetes. In closed, poorly ventilated, heated premises Aspergillus and Syncephalis fungi dominated. In micromycete communities developing on heated moist brick walls Acremonium, Spiromyces, Oidodendron, Chrysosporium, Aspergillus, Paecilomyces, Doratomyces, Stachybotrys, Syncephalastrum, Gonatobotrys were sometimes recorded. Buildings so contaminated are very hazardous from the mycological point of view because fungal propagules from the premises spread throughout the whole building, harm the building itself and people working or visiting the building.

• People spend ~ 90% of their time in buildings • Buildings represent a new and mostly unstudied habitat for microorganisms • People are affected in both positive and negative ways by microorganisms • Architects may be able to create healthier buildings by influencing the composition of resident microorganism communities, through daylighting, natural ventilation, or material selection.

surfaces become covered with flour-like chalky layer (Figure 9). The basement premises, which have been used as a gym, later a depository of books and are now used as a storeroom, have walls covered by blotches of various colours. From the brown blotches the following micromycetes were isolated: Aspergillus (¼Eurotium), Wardomyces, Acremonium, Chrysosporium, Volutella, Penicillium, Mortierella; from light-coloured patches on the walls – Mortierella, Trichoderma, Geotrichum, Aspergillus, Coemansia; from black patches on the walls – Doratomyces, Aspergillus, Phoma, Humicola, Arthrinium, Cladosporium; from plaster flaked from the hall wall – Aspergillus, Paecilomyces, Mucor, Aureobasidium, Cladosporium, Trichoderma, Penicillium fungi.

• ~ 40% of the world’s population lives in earthen dwellings (UNCHS) • Alternative building materials interact differently with the environment • Alternative building materials have lower embodied energy • Alternative building materials are easily degradable

Fig. 10. Aspergillus versicolor fungi isolated from Verkiai Palace premises contaminated with organic pollutants, �1000.



Concrete Strawbale

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How Alternative and Low-Energy Building Techniques Affect Indoor Microorganism Communities