https://www2.purpleair.com/products/list 对我来说，他们似乎是一家销售产品的公司，他们的地图是次要的。他们甚至在地图上宣传他们的东西。

“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.