Room air is 20%. 0ne Liter increases the FIO2 4%. So 1L =24%, 2L=28% and so on to 6L=44%, do not use a cannula above 6 lmp. Becomes uncomfortable and dries out the nares and can cause bloody noses due to lost humidity.
I don't understand the Related Link well enough to know if it answers your question, but you can check it out and see if it does.
The percentage of oxygen delivered by nasal tube is 24% at the rate...
You should wash your cannula with soap and water at least twice a week, and replace it at least once a month. If you are sick with a cold or similar infection, you should replace your cannula...