According to your link in an earlier post (the one about Asian air pollution), it scores better than Japan, so now you are basically trolling.
Places in Asia I have been where Taipei has better air than:
-all of China
-Ho Chi Minh
-all of India
-Singapore (not always but various times in the year, especially burning season)
-KL (same as Singapore)
-Los Angeles (many neighborhoods are basically Asia)
I cannot speak for Taichung because I find the entire West Coast of Taiwan to be a shittier version of Taipei County and avoid that entire side of the island, but what I experience in Taipei and down the East Coast as well as the Southern tip to be not bad at all.
There is plenty for foreigners to whinge about on here, and plenty of things for contrarians like HH to post about but air pollution isn't one of them. :2cents: