Free but not useful

This is one of the very few app that display air quality data for different counties and its free. Unfortunately the UI has some serious issue that makes it not very useful.
Navigation using a bar pop up from
left hand side is weird.
Apparently it can only display current location. I cant figure out how to tell it to display another city by default nor how to display multiple cities data in one screen for comparison.
To the author, how about make it better and charge a few bucks?

hayashi3 about Global Air Quality - Real Time Air Quality Indices