This app was mentioned in 9 comments, with an average of 1.33 upvotes
I use the app Plume (for iOS or Android) to check the air quality. You can search for various major cities in Korea, and it can show a historical graph for the last six months or so. (Just click the calendar button in the upper right corner in the app to switch from day view to week or six months view.)
There's also Plume, it uses Copernicus Sentinel satellite data to estimate and predict the European CAQI (or Chinese AQI if you want to):
Slightly more rough, but it does predictions, which is nice.
Their Android app is pretty slick, too.
I've been switching between various air quality apps the last month or so and found Plume to be the best one so far.
https://play.google.com/store/apps/details?id=com.plumelabs.air&hl=en
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https://apps.apple.com/au/app/air-quality-by-plume-labs/id950289243
Yo tengo una muy buena : https://play.google.com/store/apps/details?id=com.plumelabs.air
Plume is fantastic. And completely free too. Not open source though I'm afraid...
Check plume it has got nice interface
Link:https://play.google.com/store/apps/details?id=com.plumelabs.air
j'utilise cette app : https://play.google.com/store/apps/details?id=com.plumelabs.air