 This study evaluated changes in indoor, outdoor, and total exposure to PM 2.5 during the heating season in a rural village in China, finding that indoor exposure accounted for up to 95% of total exposure during the heating period. The study also found that indoor coal combustion resulted in an increment of about 62 plus or minus 12 mu gm3 in indoor PM 2.5 exposure, and that the overall exposure increased by 13 mu gm3 during the quarantine, despite a decrease in outdoor exposure. These findings highlight the need for clean HH energy transition actions to eliminate traditional solid fuels and reduce air pollution exposure. This article was authored by Jin Pengli, Yatai Men, Xinlei Liu, and others.