IQAQ-4M Environmental Monitoring Four-in-one Air Quality Sensor RS485IQAQ 4M Environmental Monitoring Four in one Air Quality Sensor RS485 The IQAQ 4M Environmental Monitoring Air Quality Sensor is a special sensor designed for environmental monitoring. The built in core sensors are all imported components. The sensor can continuously monitor the four types of PM2. 5 PM10 air quality concentration, atmospheric pressure and ambient temperature and humidity. Each parameter value is converted into MODBUS RTU standard