G'day Steve, I am currently permanent resident in Australia and
originally came from here, asthma is rampant here and has been an
incredible hobby for me.
As you have experienced with your travels, wherever you go pollutant
kinds of circumstances are virtually unavoidable wherever major
civilisation circles exist.
My current location is such that even lighting a fire in your backyard
is liable to a fine, so things are being geared toward anti-pollution
to a fair degree, if your vehicle has a smoky exhaust you will be put
off the road and fined, if you spin your wheels and make smoke you are
also liable.
One town here has even banned cigarette smoking completely within it's
city limits, most other places have really victimised smokers almost to
obscurity.
As smoking was banned here progressively in buildings, smokers tended
to congregate outside the doorways of buildings, now it is law that no
one smokes within ten metres of any public doorway, so things are on
the move at last, at least in that area. (and this is actually
enforced)
In that I have been involved trying to analyse how and what asthmatics
have been affected by within their homes for over thirty years as an
all consuming hobby wherever I have visited, it becomes interesting in
relation to your views on pollution, typically  many sufferers are not
so much affected by the outside air as they are by the interior of
their homes the furnishings and the chemicals they use which are
usually most responsible for their problems.
Conversely Singapore at certain times of the year becomes really bad
with blanketed smog, it is a "get-out" kind of city, you get there then
you get smartly out. Of course this is dependent on the time of year
the winds and the fires in Indonesia.
As you would be aware, once you understand more about how disasterous
this rotten asthmatic problem is, the more concerned you become for
action in some way, mine is with what I do, but I have had many friends
with similar outlook to yours where they were going to stand fast and
act alone.
This I would compare to someone walking in front of an enemy tank which
was supported by infantry.
Heroes maybe, but not very sensible, so I do strongly suggest anyone in
this predicament get out it. In my experience over the years those
kinds of die-hards did learn that human life is only a flash in the
scheme of things and the best way to enjoy it is to avoid pit-falls
using applied intelligence, the thing often forgotten is that genetic
makeup is affected downstream, so staying in a problem area may have
further effect in later generations. I do feel it is a responsible
action to get your off-spring away from problem possibilities.
Believe me I know exactly where you are coming from but it certainly
makes a different discussion item when outlooks are compared.

Cheers, Merlin.