If you don't want airthings to own your data, do not upload it to them. Airthings has a git repo allowing you to read your own data, keep it inside your networ

If you don't want airthings to own your data, do not upload it to them. Airthings has a git repo allowing you to read your own data, keep it inside your network, and graph it with graphana or anything you want. However if you use their free, er, no charge service to view your data, then they own what they upload. If you want to own your data, buy the airthings, don't use their service, and do anything you want with your data.