The influence of barometric pressure on a CA room
Atmospheric pressure is simply the weight of the atmosphere above the Earth. It is also called barometric pressure, because an instrument called a barometer is used to measure it. Many weather forecasts state barometric pressure in inches or millimeters of mercury; the “normal” or standard barometric pressure at sea level is 760 millimeters of mercury. Meteorologists, however, commonly use units called millibars to define barometric pressure, the sea-level standard being about 1013 millibars.
High pressure occurs where a broad column of air in the atmosphere sinks toward the surface. This very slow downward movement adds to the atmospheric pressure beneath the falling air, causing the pressure to be higher than in nearby areas where the air is not sinking. (source: https://sciencing.com/happens-barometric-pressure-rises-23369.html)
There is a relationship between barometric pressure and a CA room. Differential pressure develops between the air in the room and the outside air. When the room is 100% gas tight there will be no issue with the oxygen level in the store.
Air is denser in a region of high pressure, so the air pushes out toward less dense regions. If the room is not sufficiently gas tight the air pressure difference will be equalized via the leakages. Increasing pressure unfortunately results in an increasing level of oxygen in the room.
Enclosed graph shows the atmospheric pressure and the “risky” relationship with the CA room