What characterizes maritime polar air mass?

The maritime polar air mass is characterized as moist and cool due to its origin over cold oceanic regions, typically in the northern latitudes. When air moves over the relatively cooler waters, it picks up moisture, which can contribute to increased humidity. The air mass retains cooler temperatures as it is influenced by the cold sea surface. As it travels over land, it often brings cloudy, damp conditions and can lead to precipitation in the areas it affects. The cool temperatures are a result of the air’s proximity to its source over cold oceans, which contrast with warmer air masses that originate over land or warmer waters. Thus, the moist and cool nature of maritime polar air makes it distinct from the other air mass types described in the question.