Aranet4 is a free Android application developed by SAF Tehnika AS that allows you to connect your smartphone to an innovative indoor air quality monitor. The monitor measures CO₂ level, temperature, relative humidity, and atmospheric pressure, and the app provides numerous additional features.

With Aranet4, you can access real-time data and store up to 30-day measurement history locally. The app also allows you to analyze your measurement history with all-new charts and enjoy color-coded graphic visualizations of the CO2 levels. You can set measurement frequency to 1, 2, 5, or 10 minutes, adjust CO₂ thresholds and set buzzers, change temperature and atmospheric pressure units, calibrate CO₂ sensor, export stored data, update firmware, and much more.

The app supports multiple languages, including English, French, Latvian, Danish, Finnish, Swedish, and Norwegian. Overall, Aranet4 is a useful tool for anyone looking to monitor and improve indoor air quality.