Cold dry air
There are cold and dry air that exists in a continental polar air mass
The air mass indicated by cold dry air is a continental polar air mass, designated as cP. This air mass originates over cold land regions and brings cold, dry conditions when it moves into other areas.
A continental polar air mass forms over land in northern Canada. A continental polar air mass forms inland from the oceans of Northern Russia, Siberia and Northern Canada.
Continental polar is indicated by composed of cold dry air.
Continental polar and continental tropical are alike in that they are dry air masses. The different between the two is that the continental polar is a cool air mass while the tropical is a very hot mass of air.
continental polar
A continental polar air mass forms over land in northern Canada. A continental polar air mass forms inland from the oceans of Northern Russia, Siberia and Northern Canada.
A continental polar air mass would typically form over Central Russia. This air mass is characterized by cold and dry conditions that originate from the polar regions.
the continental tropical and continental polar air masses both come from land, are humid and their differences are polar is cool air while tropical is warm air
maritime polar, maritime tropical, continental polar, and continental tropical
Humidity is typically low in a continental polar air mass because this air mass originates from high latitudes where the air is cold and dry.
The typical aanswer to that is indeed continental polar and maritime tropical, but it is not necessarily the case. A continental tropical air mass may take the place of the continental polar air mass. In some cases, no collision of air masses is needed.