What occurs with humidity levels when air is compressed?

When air is compressed, its temperature can increase, and the capacity of the air to hold moisture also changes. Specifically, as air is compressed, the increase in pressure raises the temperature of the air if heat is not allowed to escape. Since warmer air can hold more moisture, the relative humidity of the air increases as it is compressed.

This concept is rooted in the relationship between temperature and humidity. Relative humidity is defined as the amount of water vapor present in the air compared to the maximum amount of water vapor that the air can hold at that temperature. Therefore, when the air is compressed and its temperature is elevated, the amount of water vapor it can hold increases, subsequently leading to higher humidity levels if no moisture is added to or removed from the air.

In practical terms, this is often observed in processes such as the operation of air compressors or in meteorological phenomena where air masses are forced to rise and compress, affecting humidity and potential precipitation levels.

Other options might suggest different scenarios regarding humidity levels, but they do not accurately capture the effect of compression on air and its moisture-holding capacity.