[nutjob2]

Exactly. The comparison with Indonesia is interesting, which has a similar climate, but isn't as rich or developed as Singapore.

Air conditioning is actually very conducive to colds and the like. When you go from outside to inside you're usually sweaty and the air conditioning tends to make you too cold until you dry out. I've caught way more sniffles in the tropics than in the freezing climates.

[tim333]

Anecdotally, I flew from Bali to Singapore today and there seemed to be a lot more sniffles and coughing in Singapore. In Bali the architecture is very open with lots of fresh air, scooters being popular for transport whereas in Singapore they tend more to sitting together in air conditioned boxes of various types (buildings, busses etc).