Metric units

Would you be able to explain how to calculate mass airflow in metric units?

Mass airflow can be measured in grams/second or kilograms per hour usually with liters per hour for volume flow. Non metric units are pounds/hour usually.

ECUs use metric units for actual calculations, but users in USA especially are just used to using the old style units (pounds per square inch, cubic feet per minute, pounds per hour, etc). So the ECUs have options to display in those units, and lots of times people discuss in those units (15psi of boost etc)

you might find this useful. it's kind of math heavy. It's from a Bosch document.