To determine if your air purifier is working effectively, observe the reduction in dust accumulation, allergens, or odors in the room. Many modern purifiers come with air quality indicators that display real-time air quality levels. Additionally, checking and comparing the filter's cleanliness over time can provide insight; a dirtier filter indicates the purifier is capturing pollutants. Listening for consistent operational sounds and ensuring the device's airflow isn't obstructed are also good indicators of its functionality.