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

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 low-energy 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.

Abstract:

Why Study Microorganisms in Buildings?•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•Architectsmaybeabletocreatehealthierbuildingsbyinfluencingthe

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 micro-

mycetes 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.

The premises with higher organic pollution levels were

contaminated with Aspergillus (Figure 10) Absidia,Mucor,

Thamnidium, Acremonium, Botrytis and other micromy-

cetes. 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 some-

times 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.

Study of an Old Reconstructed Building used for Various

Purposes in Savicius 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 micro-

organisms 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 micro-

mycetes developing in the stonework. The dampness and

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

Fig. 8. Ceiling damaged by Penicillium fungi in the Economic andCommercial Centre of Poland, �1500.

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

366 Indoor Built Environ 2007;16:358–370 Lugauskas and Jaskelevicius

at UNIV OF OREGON on November 18, 2010ibe.sagepub.comDownloaded from

Ceiling damaged by Penicillium fungi in the Economic and Commercial Centre of Poland, x1500.

Why Focus on Alternative Building Materials?

Sustainability:•~ 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

Human Health:•Throughout human history, we have gen-

erally had a close association with soils and the microorganisms that inhabit them

•Children raised in less sanitary conditions, like farms, have lower incidence of auto-immune disorders, such as asthma, allergies and COPD (i.e. Hygiene Hypothesis)

Proposed Study Design:

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

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

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

Gwynne MhuireachMaxwell Moriyama

Acknowledgments:Brennan BohannanG. Z. BrownJessica Green

Biology in the Built EnvironmentEnergy Studies in Buildings Lab

University of Oregon Graduate Research Forum 2012

•High insulative properties•Susceptible to mold growth•Rapidly renewable resource

Straw Bale:•High thermal mass •High hygric mass

Rammed Earth:

Influencesofenvironmentalconditionsonmicrobialdiversity.— Kembel et al., 2012

Support for Hypothesis:

Airborne bacterial communities differ significantly between indoor andoutdoor environments. In this study, the relative abundance of human-associated bacteria and potentially pathogenic bacteria was higher indoors.

Building Design and Microoganisms:

•Temperature •Relative Humidity•Surfaces

•Daylight •Wind •Ventilation Air

•Occupants•Modes of Dispersal