Method Charcoal CO poisoning question

[Jacquelyn]

The PPH did a study on CO produced by charcoal. They placed 1.5kg of burning charcoal in a 20ft shipping container.
The CO levels peaked about 70 minutes into testing. It got to 1%, then to 1.2%, then back down below 1%. All in less than 20 minutes.
Since the deadly level of CO is 1% minimum, this raises an important question.

Can you increase the CO level by just burning more charcoal? 1.5kg is a very small amount, so if you were to use, say, 10kg, could you get levels of 2% or higher for way longer than 15 minutes?
If not, this method really doesn't seem to be reliable. https://i.imgur.com/uLFO3Jx.png

 

[a.h]

1% (which is 10 000ppm) CO is not minimum to be lethal. About 400-800ppm is also lethal if person sleeps a night in it and it stays that high. 1% is just certain and peacefull for sure since it knocks one out right away ( after 1-2 breaths and kills in 1-3 minutes).
More coals produce more CO. I think that it would be good to have a meter if using coals because people don't always get high amounts of CO when using them.