Pounds per square foot
Pounds per square foot (psf) is a unit used in the United States, United Kingdom and some other countries that use the Imperial system. It is the pressure of a one pound on an area of one square foot.
Millibar
A millibar (mb) is a metric unit of pressure equal to 100 pascals, or one hectopascal. Standard atmospheric pressure at sea level is 1,013.25 millibars, and weather forecasts quote air pressure in them.