Their API is great. I found their site a little slow for something I want to check regularly so I built a faster one based on the API: https://aqi.today https:

Their API is great. I found their site a little slow for something I want to check regularly so I built a faster one based on the API: https://aqi.today https://aqi.today If there's a PurpleAir sensor near you, it will show you the reading instantly. It also updates the favicon so you can leave it open in the background and check the reading just by glancing at the tab.