What is the difference between polar marine air and Arctic air?

Following your comments on the numerical weather forecasts, I have realised that when Arctic winds blow, it will be very cold, and when polar maritime air arrives, it will also be cold, but not as cold, and wet. Until now, I thought that the Arctic lay in the polar regions (or vice versa), or in any case that it was the same direction. Meanwhile, it turns out that Arctic winds are colder than polar winds, and that snow from polar directions is wet, while that from the Arctic is dry. Where is this meteorological Arctic then, and where are these meteorological polar regions? Because geographically speaking I suppose they are in the same place?

In meteorology, the circumpolar area north of the 70th parallel is taken to be the Arctic area. The air over this area, which is covered with snow and ice (melting snow and ice in summer), takes on certain characteristics that distinguish it from air formed in other regions and is called Arctic air. (AA)

The second area over which an air mass is formed that is radically different from the previous one is the area of subtropical highs (the Azores High in the Atlantic). The northern boundary of this area is near the 45th degree of latitude. The air residing in the Azores High area is warm and humid and is called tropical air (TA). When it reaches us, we experience it as mild air; no other air mass has this characteristic.

The remaining part of the Atlantic, located north of the 45th parallel, in meteorological nomenclature is the polar area; here the polar air (PA) is formed. It is intermediate between warm and humid tropical air and cold and low vapour Arctic air.

We therefore have three air masses; two fronts are sufficient to separate them. The Arctic front separates the AA from the PA, the polar front separates the PA from the TA.