TL WL1030 Air quality monitor Air quality sensor for monitorung of indoor air quality Non-dispersive infrared (NDIR) gas sensor with CO2 measuring range up to 5000 ppm Ventilation recommendation on basis of CO2 concentration in the air Indoor temperature display in °C or °F Indoor humidity display MIN/MAX value memory of last 24 hours with auto-scrolling feature Adjustable CO2 value alert with obtional alarm sound Adjustable alert for high or low temperature and humidity Calibration feature for CO2, temperature and humidity Low battery indicator Built-in ROM memory to save settings Backlight with adjustable brightness levels Table standing CO2 levels and guidelines Below are some CO2 reference levels in general: 400~600ppm Background (normal) outdoor air level. 600~1,000ppm Typical level for occupied spaces with good air exchange. 1,000~1,500ppm Start ventilation of the room. 1,500~2,000ppm Level associated with complaints of drowsiness and poor air. Ventilation recommended! 2,000~5,000ppm Level associated with headaches, sleepiness, and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present. Ventilation strongly recommended! >5,000ppm Exposure may lead to serious oxygen deprivation resulting in permanent brain damage, coma, and death. Requires immediate ventilation!   TECHNICAL DATA Power supply: Power supply (included) Temperature range: 0°C - 50°C / 32°F to 122°F Temperature resolution: 0.1°C Humidity range: 20% - 95% RH Humidity resolution: 1% Operating temperature: 0°C to 50°C / 32°F to 122°F