https://www2.purpleair.com/products/list 나에게 그들은 제품을 판매하는 회사처럼 보이고 그들의 지도는 부차적입니다. 심지어 지도 자체에 자신의 물건을 광고하기도 합니다.

“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.