The iOS weather app’s air quality index appears to be based on the user’s country, causing confusion between countries with differing definitions of good air quality. Screenshots show the same data reported on the “Dutch scale” and the “German scale,” with vastly different good ratings. The data source, BreezoMeter, is the same for both. It’s worth noting that Amsterdam’s air quality is rated “insufficient” on the Dutch scale and “good” on the German scale, both with a value of 7.
https://intergalactic.systems/posts/post-1965946732.html