You should do the 10 cm away test on somone else, someone who you think does not smell from his/her mouth.
If the yellow and red signal lights, than sensor is detecting steam (water particles) comeing out from any mouth.
We all loose some water through breathing.
wS
You write:
"When I blow in the sensor through my mouth (10 cm away from the sensor), yellow and red signal lights turn on and purifier automatically start to work in the strongest mode."