Is it a Damage Health, Damage Stamina, Lingering Damage Health, or Lingering Damage Stamina effect? .... And does it depend on the Alchemist?

Stamina damage while in the cloud, but not lingering. Perhaps magicka damage, actually. You'd expect it to affect your clarity of thought.

A monkey’s fart should smell like a banana.
English farts should smell like cups of tea.
The farting of a fairy
Should be very light and airy.
When a father farts, I hope you'll think of me (think of me).
An Irish fart should always lilt with laughter.
It should melt your heart and melt your shorts as well.
A lion’s fart should roar with power.
Cuckoos should fart every hour.
A nun’s fart should have meaning but no smell.
A strong man’s fart should roar out like a trumpet.
A pretty girl's should barely even squeak.
But the person you can trust
Is the one who'd rather bust
Than ever let one rip right in the street (right in the street).

More of a drain stamina, cast on self, with an area effect. But I don't know how that equates to Skyrim's magic system.

And yes, ingredients, preperation, and inate skill does play a role.

Not that I've cleared a room in real life or anything...

weak poison, also, low level characters should flee.

Lingering magicka damage, direct stamina damage while in cloud. You're impaired while in it and the repulsive stench consumes you for moments afterwards.

Ask a Dunmer; the Nords call the eruption of Red Mountain a mountain fart

Whiterun Soldier, "You wouldn't understand. You're not a Nord."

It should also cause all children in the area to burst out in fits of laughter.

Damage health 300 points. Paralysis 300 seconds.

:D