The answer to 'why is my dryer vent dusty' is that a buildup of lint and debris in the dryer vent is a common issue. Over time, lint and dust from the drying process can accumulate in the vent, reducing airflow and causing the vent to become dusty.
Some common causes of a dusty dryer vent include not cleaning the lint trap regularly, a vent that is too long or has too many bends, and a vent that is not properly sealed or insulated. This can lead to reduced efficiency, increased energy costs, and even fire hazards if the lint buildup becomes severe.