Question

What is the difference between ventilation rate (liters per second) AND breaths per minute?

Answer 1

Bradypnea is an abnormally slow breathing rate so the normal breathing rate for an adult is in between 12 and 20 breaths per minute.  

Ventilation rate it is absolute amount of inflow of air per unit time. That is litre per second. Or in cubic meter per hour. In it the relative amount of inflow of air changes the rate of air per unit time.

The difference is in the steady state concentration of a pollutant that is determined by generation rate and the absolute ventilation rate but not breathe rate this is for the purpose of long term exposure controlling .

Ventilation rate is the amount of outdoor air which is that given to room in the return of air. It is specified in litre per sec due to based on many factors as like room volume , number of occupants, contaminations.  

Breathe per minute is number of breathe taken per minute. Normal it is 12 to 20 breathe per min.