@ vicar: OK, accepted.

It's just that, after 16 years in mainland China, I've heard way too many non-Chinese over-generalize about the supposed characteristics of Chinese people, and also way too many Chinese over-generalize about the supposed characteristics of non-Chinese (or, sometimes, of only 'westerners' - still a rather large population, worldwide).
No, not in every instance of the use of the word 'they' or 'them' (or equivalent in Chinese) does this reflect scarily simple mental attitudes, but I'm afraid it often does. Cf. discourse concerning Muslims generally over the past 18 years of so.
Where I grew up, this sort of general practice was a reflection of something very serious, and it seems to be alive & well today.
I agree it's annoying when people with bad breath cough in one's face, okay? But I mean it when I say it doesn't happen to me, and I've ridden a lot of buses here.

'They' meaning...?

I presently have a cough, quite a few other people seem to as well, but I haven't noticed anyone literally coughing in my face (well, perhaps a child, but I don't remember any incidents), nor have I coughed in the face of others.
'They'? Does your language accurately reflect your thought processes?

Well, there's an emergency telephone number, 3 digits (similar to 911 in the US), but I can't remember what they are. Best bet is probably to get the person to a hospital emergency room as soon as possible in a vehicle of convenience.

@Mr Pink: Your theory about Chinese liking spicy food doesn't hold up, as Chinese food is by no means spicy everywhere. As for taste discrimination, there are few Chinese who are less adept at distinguishing the subtlety of the many varieties of Chinese tea than I, a non-Chinese, am. And I like dark roasts - as do, for example, the French, Italians, Turks and some other peoples who are really into coffee.
If you can't stand to ride the bus here, you might consider that at least a tiny part of the problem might be your own, and not that of the 1.5 billion around you.

Why do you think that 'dragon's breath' might apply to 'all Asians'? Which Asians are included in 'all Asians'? Do you imagine that 'all Asians' have bad dental care or bad hygiene and eat spicy food or have some cultural attitude that you can, and should, help fix?
I wonder how you manage to survive here.
Note that I am not objecting to better dental care, or toothbrushing as a partial preventive of tooth decay and disguise of the odor of human breath without it, for anybody.
One thing I think is probably true: the recent, more rapid decline in smoking in many areas and the slower decline in China helps many Chinese to get along without so much offense concerning odors of smell. I'm a smoker, no excuses, and I am not promoting smoking as a particularly good solution, but you might consider taking it up, Mr. Pink.

@dazzer: Yes, but we also have to think about sustained attacks by the owners/controllers of the press - who, thanks to their positions and vested interests, rarely go without their own agendas - on the ability of the ordinary person to think straight. (Note: see Noam Chomsky's MANUFACTURING CONSENT (about 1987); see Edward Bernays' (Freud's nephew) PROPAGANDA (about 1930), who thought it was a bad idea to just let the ordinary person think for him/herself. Bernays was an inspiration to Goebbels - more worrying today, he probably had more to do with the rise of US advertising and electoral political strategy than any other single individual. Different ways to skin cats. None of this is irrelevant today).
And then there's the problem of people lying to themselves.
It's a long tricky question, and one of the more worrying results of it has been the attitude which many people seem to have, or maybe used to have, that when something appears in print it's either objective fact or is based on some impartial weighing of simple objective facts. I once knew a Hungarian woman back when Hungary was dominated by the Soviet Union who became visibly worried when told that many Americans simply believe in what they read in TIME Magazine. Her comment was that everyone in Hungary read the newspapers daily and was too savvy just to believe in printed words, and well understood how to read between the lines.
The ultimate watchdog on power can only be the people, an informed people, and, given what they are up against, that is no simple matter.