> many countries have their own laws and policies regarding air quality exposure. Often times these regulations use metrics about time-average exposure (e.g. the annual average 8-hr maximum ozone concentration) and can't trivially be converted between agencies. It causes very negative user experiences when your air quality summary disagrees with what a regulatory agency is putting out to the public due to a measurement technicality

Ultimately, why not simply compute it and give the user a warning that the local measurement isn't compatible with proper AQI measurement?

Also, does my body magically changes the way it reacts to air pollution as soon as I take my first step abroad?