Heating, ventilation systems, fresh air systems, air conditioning systems, and purifiers all detect exhaust gases by controlling dust sensor modules.

Air quality sensors are multi-wire sensors, usually with multiple output options. Information is generated as a Pulse Width Modulation (PWM) signal or I2C concentration value output from the output pins. In automatic mode, once the pollutant concentration exceeds a preset value, the system control module needs to evaluate the information from the air quality sensor and process it accordingly.