2016 Progress Report: Climate Change Mitigation in Low-Income Communities in Colorado: Home Weatherization Impacts on Respiratory Health and Indoor Air Quality during Wildfires

EPA Grant Number: R835752
Title: Climate Change Mitigation in Low-Income Communities in Colorado: Home Weatherization Impacts on Respiratory Health and Indoor Air Quality during Wildfires
Investigators: Miller, Shelly , Adgate, John L. , Carlton, Elizabeth , Humphrey, Jamie L. , Root, Elisabeth , Shrestha, Prateek
Current Investigators: Miller, Shelly , Adgate, John L. , Carlton, Elizabeth , Root, Elisabeth
Institution: University of Colorado at Boulder , The Ohio State University , University of Colorado Anschutz Medical Campus
Current Institution: University of Colorado at Boulder , Colorado School of Public Health , University of Colorado at Denver
EPA Project Officer: Chung, Serena
Project Period: November 1, 2014 through October 31, 2017 (Extended to June 30, 2018)
Project Period Covered by this Report: November 1, 2015 through October 31,2016
Project Amount: $999,899
RFA: Indoor Air and Climate Change (2014) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Climate Change , Air


With this research, we will assess the following questions: (1) Is there an association between residential air tightness, air exchange rates and respiratory health in low-income communities? (2) During large wildfires, which are increasing in number and magnitude due to climate change, how do particulate levels in homes vary with air tightness?

Progress Summary:

Our field campaign is now in full swing and started in fall 2015. Project staffing was completed in June 2015 when the project postdoctoral fellow and field staff were all hired. Recruiting and study execution was delayed because our original planned collaboration with the Colorado Energy Office was cancelled. We subsequently were able to collaborate with Xcel Energy of Colorado, Habitat for Humanity and Boulder Housing Partners. We have completed 126 home visits as of December 2016. In addition, we were able to enroll five homes for the fire study.

On average, the 182 participants in this study are middle-age adult females who have never engaged in tobacco smoking. In our study population, 19.7 percent of participants have ever been diagnosed with asthma, while 12.5 percent of participants have a current asthma diagnosis. Forty-five percent of our sample are of Hispanic or Latino origin, 68 percent earn less than $25,000 per year, and 60 percent have a high school diploma or less. Pulmonary function tests were completed on each of the 182 participants currently enrolled. Data from these tests, as well as subjective health measures, are currently being analyzed.

ACH50 values ranged from a minimum of 2.73 to a maximum of 38.38 with an average of 11.93 and standard deviation of 6.70. Homes in this sample were recruited from cities across the Front Range, including Denver, Aurora, Boulder, Longmont and Fort Collins. Comparing homes with and without energy efficiency upgrades, we find statistically significant lower ACH50 values among homes with installed upgrades (t = -3.65; p < 0.001). In addition, we found a statistically significant relationship among the number of energy efficiency upgrades installed and the homes’ ACH50 value (F = 5.55; p < 0.001), such that as the number of upgrades designed to tighten a building shell are installed, the home's ACH50 decreases.

First homes were enrolled in the fire study during summer 2016. We found it more difficult to identify fire-related air pollution episodes than we had anticipated. Most of the fires during 2016 that impacted the Denver metro area were from far away, and we had only a handful of Colorado-related fires. We found also that it was difficult to recruit homes for a second monitoring visit. Thus, all data collected to date were for fire-related events. To remedy this in the future, we increased our incentives to $25 per visit instead of $25 total. Results were that the fine particulate matter (PM2.5) indoor-to-outdoor ratios were close to one for three homes, 0.3 in one very clean home, and 8 in one very dirty home. We did observe that outdoor PM2.5 is typically higher than indoor levels, except during cooking events. Finally, the formaldehyde levels ranged from 3.9–29 ppb, all below the recommended limit of 27 ppb, except in one home that had been weatherized, where it was 29 ppb.

Future Activities:

We are in the process of sending recruitment material to 11,027 homes between January and April 2017. We anticipate completing about 100 home visits for our main study and at least 25 fire study visits, depending on the fire season this year. As of January 31, we have scheduled 18 main study homes and have at least five homes already interested in participating in the fire study.

Journal Articles:

No journal articles submitted with this report: View all 6 publications for this project

Supplemental Keywords:

Energy efficiency, blower door, ventilation, air exchange rates, forced expiratory volume, ACH50

Relevant Websites:

Home Weatherization Indoor Air Quality & Health | University of Colorado Boulder Exit

Climate Change Mitigation in Colorado: Home Weatherization and Indoor Air Quality during Wildfires | Shelly L. Miller Exit

Progress and Final Reports:

Original Abstract
  • 2015 Progress Report
  • 2017 Progress Report
  • Final Report