Biomechanical ecologies: towards urban air remediation through indoor environments.

Abstract

Indoor air quality (IAQ) and inhabitant health is often adversely affected by ele-vated levels of Carbon Dioxide (CO2) and Volatile Organic Compounds (VOCs), especially formaldehyde and benzene rings. Even though these aspects of indoor air have been shown to detrimentally affect human cognitive function, health, and wellbe-ing, conventional filtration and ventilation systems, designed to remediate indoor air, have the potential to exacerbate levels of these toxic components in the air stream. The modern removal-only approach to IAQ remediation may compound another IAQ trend: decreased indoor microbial diversity. These removal-only approaches to IAQ may well have contributed to the observed development of human-mediated microbial communi-ties in indoor environments, meaning the microbial communities on the surfaces of the environments in which we live and work are often inoculated only by human interac-tion, and have very few diversifying inputs. Decreased exposure to high microbial and environmental bio-diversity has been associated with negative effects on human inhab-itant health including increased allergic reactions and atopic skin conditions, and decreased immune health overall. With these variables in mind, the beginning chapters in this thesis examine how the interaction between urban/architectural development patterns and biological evolution may have led to the development of these issues. Within this context, hypotheses and design propositions are discussed and developed that attempt to integrate plant and associated microbial communities with standard ventilation and climate control equipment as a solution to these modern IAQ issues. These meta-analyses were augmented by physical testing of some of the solu-tions proposed in the initial chapters in temporal, matrix-based, controlled experiments designed to test some of the dependent variables at different scales; from the qualities of the plant-based ecosystems to their cumulative effect on the room in which the experiment was conceived. The dependent variable tested at the pot scale was the CO2 remediation potential of each trio of pots with specified growth media and plant treat-ments, along with the relative biomass of each pot. These metrics were iterated tempo-rally to track changes over time. In addition to pot-scale testing, room-scale testing led to insights into how these systems affected the CO2 of the room in which the experi-ment is occurring. Sampling of CO2 was taken at seven locations throughout the room before and during the experiment, and was correlated to biomass increases in the room to determine how increases in biomass changed the air ecology of an entirely built-environment with no external inputs. The experimental section of this project indicated that water availability, growth media, plant biomass, and plant diversity are all statistically significant drivers of the respiration/photosynthesis balance of a plant-based ecosystem. While the integration of these results into an open system such as those found in indoor air streams is complex, this preliminary study indicates that if these drivers of the balance between cellular respiration and photosynthesis in these systems were optimized, significant changes to the CO2 levels of the room could be achieved. Integrating the results of this experiment with the previously discussed literature reviews and thought experiments may lead to pathways towards evaluating the efficacy of various plant species and growth media’s ability to support diverse indoor microbial communities, and evolve healthier indoor air streams from the single plant to the room scale. Some of the next large questions in this line of questioning pertains to the potential of extrapolating these proposed frameworks into the scales and cycling of buildings and cities, tackling global problems through the way we approach buildings and local ecologies.