Answer :
Final answer:
Introducing ventilation air to a building during the heating season typically results in decreased relative humidity because cold outside air, when warmed to indoor temperatures, can hold more moisture, lowering the relative humidity if no additional moisture is added.
Explanation:
The effect of introducing ventilation air to a building during the heating season will depend on the properties of the incoming air compared to the indoor air. Generally, if the outside air is colder than the indoor air, which is common during the heating season, and if this outside air is brought to indoor temperature, its relative humidity will decrease. This is because cold air can hold less moisture than warm air, so when the outside air is heated without adding moisture, the amount of moisture relative to its new, higher temperature capacity is lower, resulting in a decrease in relative humidity.
