The sensor is situated in a lab, it detects whether or not a dangerous gas is present in the air.
If the sensor detects dangerous gas, the LED will turn red, and the LCD will display that the air is polluted.
If the sensor does not detect gas, the green LED will turn on, and the LCD will display that the air is clean.
There is also a motion sensor by the lab door, detecting whether people enter the lab, in order to inform the person monitoring the lab whether someone may need emergency assistance.
The LCD tells the overseer how far away the occupants are from the motion sensor and displays it on the screen.
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NEXT STEPS
In order to fully clean the air in the lab, a PPM sensor would need to be added to the circuit, so that the exhaust removes dust particles from the air as well as dangerous gases. The PMS 5003 G5 is the PPM sensor that I would attach to this device.
In a real-world application of this concept, the electronic device would need to be able to communicate with external devices such as alarms which signal emergency medical services to send the information about whether someone is in the lab during unsafe air quality events.
PPM Sensor required for next steps.