[glumpyfish]

Some anecdotal experience: I travel to Asia for vacations and majority of the time, I catch a minor cold. The endless coughing and runny nose can really sap my energy. A friend suggested wearing a mask. Once I did, the air I was breathing became warmer and my throat and lungs felt less dry. It really helped a lot. I was glad there were so many others around me wearing masks so I didn’t stand out at all.

[k_sze]

I have nasal allergy. Sometimes the allergy manifests itself persistently, but as soon as I put on a surgical mask, the runny nose and irritation just stops completely.

[raverbashing]

I believe there's an association between dryness of airways and possibility of airway infection (though it's not linear, IIRC the extremes are worse)

[tekkk]

Yes! I was in delhi and kathmandu and wished that i had some mask to filter out the awful air pollution. My lungs and throat felt sore, and in the end i developed a cold which eventually led me to being bedridden for a day. I cant fathom how the regular people can tolerate that toxic from day to day, it's just awful. Maybe they cant but the overabundance of mopeds and lack of sidewalks makes me think otherwise.

[robjan]

This is actually one of the reasons: to prevent the wind and cold from entering the body [1]

[1]: https://en.wikipedia.org/wiki/Traditional_Chinese_medicine#S...