This report describes a study evaluating a community-wide program to improve air quality in a rural mountain community (Libby, Montana) by replacing older, more polluting wood stoves with new, less polluting stoves. Over the course of 4 winters, Dr. Noonan and colleagues measured PM2.5 and markers for wood smoke outdoors, in schools, and in about 20 homes before and after stove changeout. In parallel, they tracked children's respiratory symptoms (based on parental surveys) and school absences.