Weatherization impacts and baseline indoor environmental quality in low income single-family homes

Understanding the impact of energy efficiency measures on Indoor Environmental Quality (IEQ) is important to building science and public health. Data were collected at three North Carolina locations for CO2, CO, NO2, temperature, RH, formaldehyde, radon, PM2.5, PM10, particle counts, household characteristics, and weather in 69 homes, before (PRE) and after (POST) weatherization, and in 13 control homes. Comparison of IEQ data to indoor and ambient air guidelines showed the number of homes with acceptable IEQ was the same or greater after weatherization for all parameters except temperature, and PM in smoking homes. POST compliance was over 90% for CO2, CO, Radon, and NO2 in all homes, and RH and PM in non-smoking homes. Overall POST compliance for formaldehyde was 75%, and in smoking homes 6%, 24%, and 78% for PM2.5, PM10, and RH, respectively. Wilcoxon test results, at significance level <0.05, showed decreased POST levels for radon in heating season homes, RH in heating season homes without pets, 1.0µm and 2.5μm particles in homes without pets, and increased levels of formaldehyde in cooling season homes without pets, particles >1.0μm and PM10 in heating season homes with pets, and 10µm particles in cooling season homes. Chi-Square analysis identified relationships between season and CO, NO2, and formaldehyde. Positive correlations were identified for pets and particles >1.0μm, smokers and 0.3μm and 0.5µm particles, heating season and increasing formaldehyde, and negative correlation for CO2 and ventilation.