Here is a tested Arduino project that uses 3 sensor probes as water level indicator with 3 leds and one LCD display + a simple controller that turns on a motor when the water has reached the desired ...

[Jens]’ device consists of an Arduino, LCD display, and two sensors – one for acetone, ... Posted in Arduino Hacks, Medical Hacks Tagged gas sensor, keto, ketosis, TGS822.

If you believe that a PM2.5/10 sensor can also detect O1, NO2, SO2 then go right ahead and market it as an “Air Quality” sensor. I look forward to the law suits.