Final answer:
Negative air pressure is pressure lower than the atmospheric pressure. This can occur when more air is removed from a space than is brought into it.
Step-by-step explanation:
Negative air pressure is pressure lower than the atmospheric pressure. This can occur when more air is removed from a space than is brought into it. For example, when you open a vacuum-sealed jar, the pressure inside the jar decreases, creating a negative pressure. This can also happen in a building when outdoor air is removed faster than it enters, creating a negative air pressure inside.