Many of us have a common birth defect of having veins too close to the surface, inside the nostrils. During dry weather the thin skin over them cracks and they bleed. AC and heat also strip humidity out of the air and that is why I run a cold type humidifier, 24/7, 365 days a year) My H&N doc says rub vaseline to maintain moisture in the area but it also cuts my sense of smell so I tolerate the nosebleeds (this is best applied after a shower to hold the moisture in). An unscented, non petroleum based moisturizer may be something worth trying.

Colds and flu just destroy the delicate balance of things in the nostrils. (by the way there is NO scientific evidence that exposure to cold causes flu or colds). But having spent time in Southern China I would live with a bottle of waterless hand cleaner in my pocket.

I have to agree with you Bob - I would wait until I had no other medical issues, like sinus infections, prior to getting a PET.

Southern China weather is basically tropical - even in the 40's, I would imagine that the humidity is still quite high as it is in the SF Bay Area on most cold nights.