Observe (smell)

Just a quick query,
Observe (smell) , many orcs use this skill. Now whilst I realize wind direction will play a part, how do other narrators handle this in terms of how far away an orc may smell PC's, or perhaps similarly a dog may scent an approaching intrudor?

Basically what is smell range?

I know this answer is late in coming, but I saw the post and wanted to try my hand at offering a smell-range.

Using the format for Ranged Weapons, and ranges given in the Star Trek game I'd give basic smelling range something like

2 / 5 / 10 / 15 +0

And then apply range modifiers normally.

And give a +3 modifier if the wind is with the scent (blowing it towards the Orc), and -3 if the wind is against, blowing the scent away.