At least buy a pair of noise cancelling earphones; the Bose brand may be best. It costs about $300, but well worth it. It blocks out heavy breathing and minor coughs, and reduces loud coughs. If you do not hear people's reactions, your mind becomes calmer, and you cause fewer reactions in return: a positive feedback loop.
As for hot weather, I found it especially difficult to prevent myself from sweating excessively, and sweating probably makes PATM worse. I have not found a good way to overcome this yet, but if you are on vacation, your mood should be good, which should reduce PATM.
I have a pair of noise cancelling Sony MDR ZX110NC headphones. They're only $50 USD.
I avoid public transportation at all costs, especially during rush hour - so I walk and bike most places. If I take the bus, I usually throw on some nature sounds in my earbuds and close my eyes.
Regarding tropical climates, I find the humid air hydrates my skin and reduce reactions. It may be different for you.