I find the information about cf=1 and cf=atm in the API documentation confusing. In one section, it says “pm2.5_a returns channel A. This is equivalent to pm2.5_atm_a for sensors registered as indoor, and pm2.5_cf_1_a for sensors registered as outdoor.” However, another section states, “Simple running averages are calculated using the CF=1 data variant for indoor sensors and the ATM variant for outdoor sensors.” These two statements contradict each other regarding which CF is used for indoor versus outdoor sensors.