What is meant by the "stack" effect as it pertains to soil gas intrusion Question 5 options: Soil gas vapours enter the building due to the differential pressure of wind on one side of the building vs the other As warm air rises in a building, cooler soil gas vapours are drawn into a building When vapours exit a building as a result of opening windows When soil gas vapours enter a building as a result of ventilation systems (eg., heat stacks) As cool air sinks in a building, warmer soil gas vapours are drawn into a building