... ,real-time display air ppllution index; 2,the air tester is test VOC, dust bacteria, stink,weat, etc; ... to take a breath or leave the room harmful gas: 0-99 0-30(green light) represent ... (red light) represent high harmful gases5, when harmful gas display light is red, it will alarm, remind ... stink, sweat, etc. VOC is test the organic volatic gas in the air, mainly tolunene, xylene etc(home decoration ...