Hi,
I just bought a PurpleAir device and went through the registration step for the first time.
You might want to know that the embedded terms of use and conditions on the PurpleAir device registration page still have the version from June 1, 2017. It very closely matches this old version on the Internet Archive from around that time: Terms Of Use - PurpleAir
i.e. They do not quite match the terms of service as the publicly listed version that was updated July 18, 2022: Terms of service – PurpleAir, Inc.
You might want to update them or just link to the more up-to-date version from the registration page.