Research shows that dryer sheets are actually a source of air pollution, because of the chemicals that they contain. When put in air vents, the exposure to the fragrant chemicals is increased and is constantly irritating the eyes, nose, and airways. This can potentially cause an onset of allergies in susceptible individuals and other types of irritation. Additionally, they block the circulating systems and worsen the airflow, so no, you shouldn’t put the dryer sheets in your vents.