Remediation of Chemically Contaminated Buildings to Improve Indoor Air Quality

Introduction protein allergens, mold and dust mites, from indoor air. Chemical contamination of indoor air results from chemical spills Objectives and manufacturing of wood- based building materials. Current The research is split into two approaches to indoor air cleanup projects: are based on the physical removal • Develop a protocol for of contaminated air by ventilation reclamation of building with or without subsequent materials (wood and concrete) treatment of the exhaust air. contaminated with toxic This approach is ineffi cient and Dr. D. Muggli with his students in the lab. chemicals that may affect wastes energy – both in hot and cold indoor air quality. climatic zones. Therefore, fi nding effi cient methods • Develop a simple and effi cient method and related of indoor air decontamination is a high priority for compact device for indoor air purifi cation. building and maintaining healthy homes with effi cient energy usage. Approach In the fi rst project, wood and concrete samples are Background contaminated with model pollutants; then either a The proposed solution is based on the use of either bioresource or photocatalyst and UV light will be bioremediation or photoremediation. Bioremediation applied to the material surface. The rate of pollutant is the application of bacteria on contaminated building removal and transformation are monitored. Preliminary materials. Photoremediation uses photocatalysts, i.e., research has demonstrated that bioremediation is semiconductors, such as titanium dioxide and a light a viable option, although this treatment is slow. source. A photocatalyst under UV light generates Photoremediation is much simpler but may not be reactive radicals that are able to oxidize any organic applicable for some pollutants. matter. A properly modifi ed photocatalyst generates In the second project, the research consists of three radicals only on its surface, without producing any steps: construction of a bench-scale apparatus, toxic by-products, such as ozone or hydrogen peroxide. formulation of the TiO -based photocatalyst, and The selectivity of the catalytic photooxidation can 2 experimental testing under varied parameters. This be varied (i.e. either specifi c chemicals or the entire research is generating preliminary data that point spectrum of organic contaminants can be removed). towards the conditions under which photocatalytic This process can be used for the removal of both removal of indoor air pollutants is feasible. Airborne chemical and biological contaminants, including

U. S. Department of Agriculture Forest Service • Forest Products Laboratory RIP-4703-002

pollutants are quantitated using gas chromatography, and pollutamt removal efﬁ ciency is calculated and Cooperators analyzed. USDA Forest Service, Forest Product Laboratory Expected Outcomes University of North Dakota 1. A protocol for the biological and/or photochemical Contact Information cleanup of contaminated building materials will be developed. Charles Frihart, Project Leader USDA Forest Service 2. The impact of building material parameters on the Forest Product Laboratory diffusion rate of model pollutants will be determined. Madison, WI 53726-2398 3. A bench-scale apparatus for indoor air puriﬁ cation Phone: (608) 231-9208 will be manufactured and tested (with a limited set e-mail: [email protected] of experimental variables). The information obtained in the present study will be used then to expand the approach to other chemical and biological pollutants.

Timeline Small-scale diffusion, bioremediation, photoremediation and proof-of-concept air puriﬁ cation studies are expected to be completed in May 2005; larger scale studies are planned to be continued to develop effective technologies.