Canadian Welding Bureau (CWB) Level 3 Practice Exam

What mechanisms produce ozone in welding fumes?

Ozone is formed by chemical reaction with nitrogen oxides Ultraviolet light alone forms ozone The electrical arc and an ultraviolet photochemical reaction form Ozone(O3) Electrical arc alone forms ozone

Correct Answer:

The electrical arc and an ultraviolet photochemical reaction form Ozone(O3)

Explanation:

Ozone formation in welding fumes is driven by the ultraviolet radiation emitted by the welding arc. The arc’s UV light provides the energy that splits oxygen molecules (O2) in the surrounding air into individual oxygen atoms, and these atoms rapidly combine with O2 to form ozone (O3). This photochemical reaction is continually fueled by the UV from the arc, so the ozone is produced by the arc plus the UV-driven chemistry, not by the arc alone or by UV light in isolation. While nitrogen oxides can appear in the arc environment, they are not the primary mechanism for ozone formation here.

Access more questions from this quiz

Continue to Canadian Welding Bureau (CWB) Level 3 Practice Exam for more practice questions and the full quiz experience.

Access More Questions