[buro9]

People with the common cold smell like dying flowers about 2-3 days before any symptoms appear.

It took me until my 30s to discover other people didn't know/realise/detect this. But since I've shared it with people as an interesting party trick type thing I've found many people who could smell onset of a cold.

It's not surprising to me that people can smell so much more, as all of our senses differ from person to person, the range, intensity, sensitivity.

What does surprise me is turning that into a useful application that could be used by others without the same sensory capabilities, that's neat.

[dmichulke]

How do you do this socially?

You're probably not sniffing random people to chat them up with "you'll have a cold in 3 days", right?

[buro9]

Not random people, no, but it's a useful signal for "that person is probably contagious right now so I'll give them a wide berth".

I have got into the habit of telling people close to me, and it gives them a chance not to avoid getting a cold, but to mitigate the impact by treating the symptoms before they've really emerged.