Air quality this year has been abysmal but not as bad as some areas. Because of the fires in mid-Michigan and Canada, there is just nothing to compare it to, we're just not near anything normal. That said, other places in the country are getting hit worse than us. How bad we do or do not have it is just massively dependent on weather patterns. I'm in SE Michigan and today the air quality is fine. On Sunday is was iffy.
All that being said, traveling in Michigan is the best from Summer through the Fall. July through October is prime time.