I suggest anyone who has/had Asthma (or any other breathing problems) to certainly make sure they pack the appropriate medications they need.

For me, my Asthma has been in remission for the past ten years - I come to Beijing and I end up having Asthma attacks left and right. Because my Asthma had been in remission for so long, I didn't have any inhalers or medications to treat it.

Beijing's air is of horrible quality, the daily smog is thick, and the locals smoke and do it to the extreme - all of this combined is perhaps what triggered my reaction.

Even if you've never had breathing problems, it's best to pack safe and bring one.