Impacts of Weatherization on Microbial Ecology and Human Health

EPA Grant Number: R835757
Title: Impacts of Weatherization on Microbial Ecology and Human Health
Investigators: Brown, G Z , Johnson-Shelton, Deborah
Current Investigators: Brown, G Z , Den Wymelemberg, Kevin Van , Johnson-Shelton, Deborah , Green, Jessica
Institution: University of Oregon
Current Institution: University of Oregon , Oregon Research Institute
EPA Project Officer: Chung, Serena
Project Period: August 1, 2015 through April 30, 2017 (Extended to April 30, 2018)
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 will examine how weatherization and housing ventilation systems impact health in the context of climate change and associated microbial indoor/outdoor environments. Climate change is affecting human health through human alteration of shelter. Weatherization (air-sealing) measures address climate change by reducing energy use and carbon emissions, but because they rely on energy-intensive and failure-prone mechanical systems to provide basic air exchange, they may alter the indoor microbial ecology to be less diverse and more dominated by human-associated microbes that have the potential for human immune dysfunction and infection. Our primary objectives are to: (1) Quantify airborne microbial communities and traditional indicators of indoor air quality (IAQ) within residential dwellings before and after weatherization of the building envelope and installation of a whole house ventilation strategy; (2) Assess seasonal air composition variations outside dwellings to understand how they affect the indoor air composition in terms of microbial ecology and IAQ; (3) Assess household building operation attitudes and behaviors before and after weatherization to understand how human interaction with house weatherization and changing air composition, in terms of microbial ecology and contaminants, impact residential health.


We will evaluate 72 single-family detached dwellings in high desert and marine climates to characterize geographic and climatic heterogeneity during two seasons of climate extremes (summer and winter) before and after weatherization using high-throughput DNA sequencing tools, architectural and ventilation analyses, health surveys and traditional metrics of IAQ. Houses will be grouped by ASHRAE 62.2-2013 whole-house ventilation strategy: ducted exhaust fan, ducted supply fan or ducted heat recovery ventilation (HRV). Health and behavior surveys will be sent to participants before and after weatherization. IAQ data will be collected to assess the impact of weatherization and the ventilation strategy, and, with microbial data, to explain variance in the health survey data, thus grounding our findings within the body of existing IAQ research.

Expected Results:

Our results will show how ventilation system design in weatherized houses influences exposure to airborne outdoor microorganisms. Our findings will inform homeowners, building contractors, design professionals and agencies administering weatherization programs. We will link innovative scientific research to multiple dimensions of sustainability, including human health.

Publications and Presentations:

Publications have been submitted on this project: View all 17 publications for this project

Supplemental Keywords:

architectural design, mechanical ventilation, public health, sustainable development, elderly, children, allergies, asthma

Progress and Final Reports:

  • 2016 Progress Report
  • 2017 Progress Report
  • Final Report