13/02/2026
Why do we measure CO in PPM ?
Why Do We Measure Carbon Monoxide (CO) in PPM?
❓ Question
Why is CO measured in ppm instead of %?
✅ Answer
Because CO is dangerous even in very tiny amounts.
So we measure it in ppm (parts per million).
✅ Easy Explanation
Carbon Monoxide (CO) is:
✔ Toxic
✔ Invisible
✔ Odorless
✔ Deadly
Even a small quantity can kill.
✅ Safe Levels of CO
✔ 0–25 ppm – Safe
⚠ 50 ppm – Harmful
⚠ 200 ppm – Headache
⚠ 800+ ppm – Death in minutes
✅ Example
Generator running near a confined space:
CO concentration = 300 ppm
Worker may experience:
❌ Headache
❌ Vomiting
❌ Unconsciousness
❌ Death
➡ So, entry is NOT allowed.
✅ Why NOT %?
Because:
1% CO = 10,000 ppm
This level is already deadly.
So, % is too large a unit.
ppm gives accurate measurement of small, dangerous concentrations.
📌 Interview Line
“CO is measured in ppm because even very small concentrations are toxic and life-threatening.”
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