Chemistry and microbiology of green building materials

While the market for “green” building materials has been expanding rapidly, no rigorous framework exists for evaluating the chemical and biological reactivity of these building materials. The objective of this research was to assess the ozone reactivity, primary and secondary VOC emission rates and mold resistance of selected green building materials. Two different sets of experiments were conducted. The first set focused on reactive consumption of ozone by ten common green materials. A screening assessment of secondary emissions of C6 and greater carbonyls was also completed for selected green materials. The second set was completed to evaluate the relative resistance of selected green building materials and their conventional analogs to surface fungal growth in moist interior environments. Ozone reactivity varied considerably between test materials. The ozone deposition velocity for inorganic ceiling tiles, for example, was two times higher than cabinetry materials and approximately fifty times higher than UV-coated bamboo. Experimental results were used as input to a simple mass balance model which predicted that the ratio of indoor to outdoor ozone concentrations was not significantly affected by green building materials. The green materials used in this study emitted less primary and secondary VOCs than did their non-green counterparts, although the difference was not significant and the material sample set was relatively small. Also, the green materials tested were not prone to either less or more mold growth than their conventional counterparts. Instead, materials composed of organic materials with high equilibrium moisture contents (EMC) were more prone to mold growth than inorganic materials with low EMC. Perlite-based (inorganic) ceiling tiles that consumed relatively large amounts of ozone without corresponding by-product formation were also resistant to mold growth. Such findings should facilitate the selection of future green building materials, both explicitly and by defining a protocol for future testing of green materials.