Altruist is two devices working as one. Urban goes outside and measures what the street does to your air: PM2.5 and PM10, temperature, humidity, pressure and noise in decibels. Insight stays in the room and measures what you actually breathe: CO2 through an NDIR sensor, shown on an e-ink screen you can read from across the table.

• Open from the firmware up. The firmware, the schematics and the open source cloud it talks to are all public. You can read the code, change it, and build on it.
• Works on its own. Local control over your own network, a native Home Assistant integration and a microSD card for history. The device keeps measuring and showing data with no internet connection at all.
• Your data, your call. Publish your measurements to the open source cloud and they join a public map, or keep everything inside your own network.

Here is how Altruist measures up, feature by feature.