Why isn't smoke pulled down by gravity?

Answer 1

It does. It just pulls the colder air around it down harder, so the air gets pulled down furtehr than the smoke. Result: smoke goes up, air goes down, until the smoke cools enough to become air.

Answer 2

Smoke rises because it is less dense than the surrounding air. As the smoke is heated, it becomes hot and less dense, causing it to rise due to buoyancy forces. Gravity does play a role in pulling the smoke down eventually, but the buoyant force is often stronger, leading to the smoke rising instead.