“Welding fumes are a complex mixture of fine condensed metallic particulate and other solid particles. While welding fume is not a gas, some gases such as ozone, NOx and carbon monoxide are also generated during the welding process,” says Keith Daley, environmental systems manager at The Lincoln Electric Company of Canada. “This is important to realize when you are trying to remove welding fume from the breathing zone of the welder.”
Positioning
Don't place your head above the weld so you’re not breathing the fumes directly. “Despite warnings and instructions, some people, when they are welding, just stick their face in it. They like to get in close,” says Daley. “What you need to do is position yourself so that the weld fume is out of your breathing zone.” This is the easiest way to avoid directly inhaling weld fumes. Unfortunately, this is a common sight in some shops and especially with inexperienced welders. Better helmets with bigger viewing areas allow welders to see the object being welded more clearly, so they don't have to crouch over the workpiece.