Albert Barnes Commentary Ezekiel 40:46

"and the chamber whose prospect is toward the north is for the priests, the keepers of the charge of the altar: these are the sons of Zadok, who from among the sons of Levi come near to Jehovah to minister unto him." — Ezekiel 40:46 (ASV)

The position of the “chamber” looking to the north commanded a view of the bronze altar and the sacrifices, which were prepared at the north side of the altar.

The sons of Zadok - The priests were all descended from one or the other of the two sons of Aaron, Eleazar and Ithamar. David distributed the priestly offices between the families of Zadok, the representative of Eleazar, and Ahimelech, the representative of Ithamar (1 Chronicles 24:3). From the time of Solomon, not only the high priesthood, but the priesthood itself—insofar as its service of offering upon the two altars was concerned—seems to have been confined to the descendants of Zadok (see 1 Chronicles 6:49–53). Perhaps the other offices, such as those mentioned in Ezekiel 40:45, were performed by the descendants of Abiathar and Ithamar (compare 1 Samuel 2:36; and see below regarding Ezekiel 43:19; Ezekiel 44:15).

The priests who had charge of the sacrifices were distinguished from the rest of the Levitical priests, as they which come near to the Lord, and (Ezekiel 42:13) the priests that approach unto the Lord.