Bonneville Power Administration indoor air quality measurements in northwest residences. Status report

One hundred sixteen existing homes were tested and screened for HCHO, NO2, water vapor, and radon using mailed passive samplers. Concentrations ranged up to 136 ppB HCHO, 28 ppB NO2, 9.28 gkg H2O (60% relative humidity at 68F), and 85 pCil Rn. Forty-eight homes with measurable levels of NO2, HCHO, or Rn were selected for more intensive monitoring to evaluate the effects of staged weatherization on pollutant concentrations. Pollutants sampled include: HCHO, NO2, H2O, CO, respirable suspended particles (RSP), and Rn. Meteorlogical monitoring occurred concurrent with leakage area measurements using blower doors and ventilation rate measurements using perfluorocarbon tracers (PFT). A separate controlled study evaluated the interactive effects of air leakage reduction and conductive heat loss reduction on the pollutant levels generated by an unvented combustion heating source. Pollutant concentrations increased after reducing infiltration with house tightening retrofits. Subsequent conductive retrofits reduced heating loads, thereby reducing pollutant generation, and indoor air pollution levels. The resulting CO2 concentrations are consistent with a proposed indoor air quality model. In addition to the study of existing homes, indoor air pollutant screening (Phase I) of Model Conservation Standards (MCS) New Homes and 'typical' New Homes began in January, 1985.