Air Quality Monitor CO, CO2, PM2.5, TVOC, HCHO, Temp/Humid (T-Z01) Have you gone nose blind to household odors or dust? Check multiple measures of your home’s air quality. This air quality monitor allows REAL-TIME accurate monitoring of temperature (in C), humidity, formaldehyde (HCHO), total volatile organic compounds (TVOC), and micron-sized fine particulate dust (PM2.5), carbon monoxide (CO), carbon dioxide (CO2). Formaldehyde is an environmental carcinogen yet odorless at lower concentrations. Detect low levels of airborne TVOCs not perceivable to the human nose.