So far this August, like past Augusts, there were many cooling degree days. Using the ideal or combined gas law, air density indoors was greater than air density outdoors daily with high A/C usage. However, indoor carbon dioxide by direct measure was typically double the outdoor concentration. Running an exhaust fan in the sleeping room for thirty minutes after vacating the room at wake-up decreased carbon dioxide in the room much more than 30 minutes after vacating the room without exhaust fan. The highest indoor CO2 level was measured the day of rain last week. The impact, typical of August, is allowing fresh air indoors & exhausting stale air without losing A/C effects. Other impact related to hazardous thunderstorms that are somewhat unpredictable for activity planning.