https://www2.purpleair.com/products/list សម្រាប់ខ្ញុំ ពួកគេហាក់ដូចជាក្រុមហ៊ុនដែលលក់ផលិតផល ហើយផែនទីរបស់ពួកគេគឺជាក្រុមហ៊ុនបន្ទាប់បន្សំ។ ពួកគេថែមទាំងផ្សព្វផ្សាយវត្ថុរបស់ពួកគេនៅលើផែនទីខ្លួនឯងទៀតផង។

“PurpleAir is built on the ideal of sharing data and by doing this, empowering individuals to effect change. All public PurpleAir data is available to download under various licenses from private, not for profit use to educational and commercial use. The common element between these uses is to share attribution.” (https://community.purpleair.com/t/about-the-data-category/70) – based on that maybe 4/5 blocks would be accurate. There do not seem to be any trackers or advertisements on the site.