Assessment of indoor air quality in interior Alaskan homes

Interior Alaska has indoor air quality issues similar to those of other far northern communities associated with long cold winters and reduced ventilation rates. Moreover, geological features in the hills around Fairbanks, Alaska increase the likelihood of elevated radon levels. To better quantify these features, our team has gathered data at 68 homes. We used CO2 concentrations as a surrogate for indoor air quality as well as to help determine ventilation rates to be used in subsequent modeling work. We found the CO2 data correlated well using basic mass conservation considerations for yearly averages. The summer CO values ranged from 1 to 9 ppm and the winter values from 0 to 23 ppm. For homes with woodstoves, we found the indoor PM10 concentrations rose after the stoves were fired up. Here PM10 refers to particles smaller than 10 mum. Over 40% of the tested homes in the hills around Fairbanks had radon levels>4 pCi/L compared to a nationwide average of 7%. Active subslab depressurization systems tested were very effective in reducing indoor radon concentrations (average reduction of over 90% for eight homes).