So I had a great trip to China last week and loved it all, except maybe the horrific traffic. I had done a ton of research on details that were important to me before I left, but it was hard to get accurate information. And I know there's a lot of sources and travel websites out there but I like to get most of my information from this site - I know the personalities that post here and I trust their advice.
So here's what I saw, focusing on the issues that I was most worried about:
I brought an N95 face mask but did not use it. Most people were not wearing them...maybe about 10% were. The air in Beijing, Shanghai and Xi'an was visibly dirty and I have asthma but I did not have any trouble breathing at all.
It is indeed crucial to carry toilet paper with you and lots of anti-bacterial wipes.
Internet is funky. In addition to the usual blocked sites like Facebook, Google etc., lots of common US sites just fail to load when you go to them. In addition, I was unable to send any email whatsoever at any of my hotels and my tour mates reported this same issue. I could receive email but not send any.
TMobile is a great resource over there because, as long as I was pulling data over my phone, my Gmail worked, I could look at Facebook and I could search on Google.