# Calculating the tidal volume ATPS (L) Watch

1. If we want to calculate the ATPS, and were given for example that the total volume of expired air (L) was 30.6 L provided that the air was collected over an interval of 3-minutes, will ATPS in this case be: 30.6 L / 3 min = 10.2 ?

Thanks.
2. If we have the following values:

- Number of breaths in one-minute = 16
- Exhaled minute volume ATPS (L min-1) = 5.50

Will the tidal volume ATPS (L) be ---> 5.50 / 16 = 0.34 ?

Thanks.
3. If we were given the following values:

- Oxygen concentration of expired air = 16.7%
- Exhaled minute volume ATPS (L min-1) = 5.67

And, want to calculate the "Oxygen exhalation rate ATPS (ml min-1)", would it be as follows?

5.67 X 16.7% = 0.95

But, since the value has to be in (ml min-1), we should multiply by 1000, so, the final result will be 950 ml min-1

Is it correct this way?

Thanks.

Updated: November 1, 2011
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