2015 Progress Report: Integrated Measurements and Modeling Using US Smart Homes to Assess Climate Change Impacts on Indoor Air Quality

EPA Grant Number: R835756
Title: Integrated Measurements and Modeling Using US Smart Homes to Assess Climate Change Impacts on Indoor Air Quality
Investigators: Lamb, Brian , Cook, Diane , Jobson, B. Thomas , Kirk, W. Max , Pressley, Shelley N. , Walden, Von P.
Institution: Washington State University
EPA Project Officer: Ilacqua, Vito
Project Period: November 1, 2014 through October 31, 2017 (Extended to October 31, 2018)
Project Period Covered by this Report: November 1, 2014 through October 31,2015
Project Amount: $996,588
RFA: Indoor Air and Climate Change (2014) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Climate Change , Air


The overall goal is to improve our understanding of the complex intersection between indoor air quality and climate change. Our objectives are to address three specific science questions:

  1. How do local climate conditions, including extremes in the range of weather conditions, affect indoor air quality factors including energy consumption, ventilation rates, occupant behavior, and indoor pollution levels, and are there generalizations that occur across the ensemble of buildings and locations?
  2. How well does the CONTAM indoor air quality model perform for the range of conditions and buildings in our Smart Home ensemble?
  3. For future climate conditions, what are the projected indoor air quality levels in a set of buildings representative of U.S. housing stocks, and how sensitive are these levels to plausible changes in building properties and human behavior?

Progress Summary:

During the first year of the project in 2015, methods and procedures were developed to measure indoor/outdoor air quality and these methods were then applied to obtain data for two test houses (H2 and H3) for periods of 28 and 13 days, respectively, during hot, summer conditions. The conditions included substantial periods with very heavy wildfire smoke in the region as well as periods without smoke. The measurements included indoor/outdoor CO2, CO, NOx, O3, various VOCs using a Proton Reaction Transfer Mass Spectrometer, and PM2.5, along with outdoor weather conditions. Each house was also fitted with occupant sensors to monitor open/closed doors and windows, and occupant activities using the WSU Smart Homes methodology (Center for Advanced Studies in Adaptive Systems Exit ). For both houses, indoor levels of most VOCs were much higher than outdoors even during the smoke periods. Formaldehyde concentrations indoors were in the range of 10 to 40 ppb in both houses. Simple chamber flux measurements of the carpet in H2 yielded a formaldehyde emission rate of 22 ug/m2/hr for the carpet or 1.8 mg/hr for the house. Using CONTAM to model indoor air quality for H2 produced simulated levels that were in good agreement with the measured formaldehyde levels, but there was a temporal offset in the model which indicates that mixing indoors and the air exchange rate were not accurately reproduced in the model.

In H2, there were periods with and without occupants at home. During the unoccupied periods, the measured air exchange (AER) rates were well represented by an empirical regression expression accounting for wind speed and indoor-outdoor temperature difference (AER = a + bWS2 + cΔT). With occupants home, windows and doors were opened in the evenings, and the measured AER exceeded the AER due to outdoor meteorological conditions by factors of 2 to 3. For PM2.5, the outdoor smoke levels were quite high, with much lower, but still elevated levels indoors. The ratio of indoor/outdoor PM2.5 levels or the penetration ratio was in the range of 10% with homeowners absent and 25% with homeowners present.

Future Activities:

During the second year, we will continue to deploy the measurement systems to test houses. During the winter/spring of 2016, measurements are being conducted again in H2 and H3 as well as in the next test home, H4. Based on our experience with the systems in 2015, we have modified our approach to address noise, power and heat issues. In the new approach, we have reduced the number of instruments in the indoor rack to avoid those with noisy pumps, and we have reconfigured the outdoor rack to sample indoors for 15 min and then outdoors for 15 min on a continuous basis. This reduces the noise issue indoors for the homeowners, but still allows us to measure all of the key species both indoors and outdoors. In summer, 2016, we anticipate testing H4 again and also homes in the Richland, Washington, area where we may be able to collaborate with other research groups working on tight homes with high efficiency ventilation systems. These measurements will occur at the same time that we are conducting an ozone field program in collaboration with the Washington Department of Ecology. This will have the benefit of doing test houses in an area where comprehensive outdoor measurements are conducted related to ozone non-attainment issues.

CONTAM modeling work will continue first with an emphasis on simulations for each test home and second to begin work on modeling the U.S. housing stock for current and future climate conditions. We have begun to assemble the downscaled climate data for this portion of the project.

Journal Articles:

No journal articles submitted with this report: View all 3 publications for this project

Supplemental Keywords:

CONTAM, indoor air quality model, building energy consumption, ventilation rates, indoor pollutants;

Relevant Websites:

Center for Advanced Studies in Adaptive Systems | Washington State University Exit
Laboratory for Atmospheric Research | Washington State University Exit

Progress and Final Reports:

Original Abstract
2016 Progress Report