2016 Progress Report: Impacts of Weatherization on Microbial Ecology and Human HealthEPA Grant Number: R835757
Title: Impacts of Weatherization on Microbial Ecology and Human Health
Investigators: Brown, G Z , Johnson-Shelton, Deborah
Institution: University of Oregon
EPA Project Officer: Ilacqua, Vito
Project Period: August 1, 2015 through April 30, 2017 (Extended to April 30, 2018)
Project Period Covered by this Report: August 1, 2015 through April 30,2017
Project Amount: $993,557
RFA: Indoor Air and Climate Change (2014) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Climate Change , Air
This study is investigating weatherization in single-family detached homes in two Oregon climate zones during the winter and summer seasons. Data in this study are being assembled from microbial sampling, air quality measures, architectural inventory and household health survey. The overarching goal in this project is to quantify the relationships between ventilation strategies, indoor air quality and microbial ecology in weatherized residential homes and their effects on human health. The study also seeks to determine ventilation configurations in which the building envelope-supplied source can be used with designed natural ventilation to reduce energy use in the majority of U.S. climates. Finally, the project intends to provide better understanding of the role of occupant behavior in building operation resulting from weatherization programs and how this affects occupant health. Our study addresses four questions: (1) What role does the building envelope play in attenuating or distributing the outdoor microbiota indoors under ASHRAE 62.2-2013 post-weatherization whole house residential ventilation systems? (2) How does the ventilation source, either duct or building envelope, influence the similarity of the indoor microbiome to the outdoor microbiome? (3) Is there a seasonal or climate influence affecting the structure of indoor microbiota? and (4) Does occupant behavior after weatherization affect indoor air contaminants and health? The resulting data will provide an empirical basis to inform the design of healthier buildings.
With Human Subjects approval, a recruitment plan for households has been initiated that includes flyers, a website, phone calls to current and past weatherization agency clients, and outreach to media outlets. Interested homeowners are entered into the REDCap system to begin the process of consent, home visits for microbial and air sampling, and completion of the home health and behavior survey. REDCap is a secure, HIPAA-compliant, web-based application designed to support data capture for research studies. We also use it to provide coordination between the project team, weatherization partners, and contractors. Comparison homes are identified and matched to treatment homes by location and assessment time, to the extent possible. Monitoring equipment packages were fabricated to contain sensors, dataloggers, and a platform for the petri dishes used to collect microbes through settling of bioaerosols. Study data are being collected, tracked and monitored using the REDCap application Exit. Early air quality data are being evaluated to notify participants if air pollutant levels exceed national standards of safety. These “hazard” checks use some of the same processing as needed for hypothesis analysis and so act as an evaluation of data quality as well as the initiation of the data analysis phase. We have finished swabbing the first batch of petri dish samples performing DNA extractions; sequencing has not been performed yet. The remaining data have yet to be analyzed. Data dictionaries are being compiled for each data type in the project.
In the coming year, the study will establish relationships with low-income weatherization assistance programs to recruit a second cohort of participants in the two climate zones. Data analysis will be completed, utilizing multivariate analysis techniques designed for ecological inference of microbial communities and to describe how environmental variables influence air quality. We will use nonmetric multi-dimensional scaling and constrained ordination techniques will be used to explore the most relevant environmental factors associated with microbial community composition and community dynamics, and discriminant analysis to test the relative importance of environmental parameters on microbial community variation. Comparisons of indoor vs. outdoor measurements will provide a description of how the building envelope and ventilation systems mediate indoor conditions. We will also analyze our samples in the context of potential source environments, and across multiple publicly available indoor microbial data sets to better understand the generality of the patterns we observe. Pre-post household survey responses will be studied using a combination of descriptive analyses, regression techniques, and mixed model analysis to compare occupant demographics, occupant-reported physiological and mental health and building operations and attitudes before and after the weatherization. We will also use weighted regression analysis to consider cluster effects of households nested within the study’s two geographic regions.
We plan an initial paper in fall of 2016, and follow-up with one or more papers in 2017. We also will present the project at the 2017 AIA Design and Health Research Consortium Convening Meeting, the 2017 Society of Prevention Research Annual Meeting, and the 2017 Sloan Microbiology of the Built Environment Conference.