You’re Seeing Water Vapor, Not Smoke

You probably saw billowing clouds on your way to work this morning. It’s important to know that these clouds are water vapor, and not smoke.

The reason for this occurrence is because of a scientific process called condensation. When you exhale when it’s cold outside, the water vapor in your breath condenses into lots of tiny droplets of liquid water and ice (solid water) that you can see in the air as a cloud, similar to fog. The same thing occurs with the exhaust from your chimney if you use natural gas for home heating because burning natural gas produces two main byproducts, carbon dioxide, and water vapor.

Despite the fact that this stuff is basic physics and chemistry, the Star Tribune was unable to get it right in their reporting of last January’s polar vortex, as you can see from the picture below. I’ve modified it so it is no longer incorrect.

Fear not, Minnesotans. The clouds billowing out of chimneys and pollution control stacks during the cold weather are water vapor, and not smoke.