According to some embodiments, a heating, ventilating and air conditioning (HVAC) system comprises a circulation fan, one or more humidity sensors operable to sense humidity data associated with an enclosed space, and a controller. In operation, the controller receives the humidity data from the one or more humidity sensors and receives air quality data associated with at least one air pollutant. The controller determines, based on the air quality data, that a threshold associated with the air pollutant has been exceeded and determines, based on the humidity data, that a threshold associated with humidity has not been exceeded. The controller operates the circulation fan in response to determining that the threshold associated with the air pollutant has been exceeded and the threshold associated with humidity has not been exceeded, the circulation fan operated for filtration purposes while not servicing any conditioning demand.