1.  Metropolitan Portland Air Quality Region.  The Metropolitan Portland Air Quality Region shall consist of the Counties of York, Cumberland, Sagadahoc and the municipalities of Brownfield, Denmark, Fryeburg, Hiram and Porter in the County of Oxford.  

1-A.  Portland Peninsula Air Quality Region.  The Portland Peninsula Air Quality Region shall consist of that section of the City of Portland bordered on the west by Interstate 295, on the south and east by the Fore River and on the north by Casco Bay and the inlet to Back Bay.  

2.  Central Maine Air Quality Region.  The Central Maine Air Quality Region shall consist of the Counties of Androscoggin, Kennebec, Knox, Lincoln and Waldo; of the municipalities of New Portland, Embden, Solon, Athens, Harmony, Cambridge, Ripley and all other municipalities in Somerset County to the south of these; of the municipalities and unorganized territory of Township No. 6, Phillips, Salem Township, Freeman Township and all other municipalities and unorganized territory in Franklin County to the south of these; and of the municipalities and unorganized territory of Stow, Batchelder, Grant, Gilead, Riley T.A. No. 1, Grafton T.A. No. 2, Andover North Surplus, Byron and all other municipalities in Oxford County to the south and east of these with the exception of those municipalities within the Metropolitan Portland Air Quality Region.  

3.  Downeast Air Quality Region.  The Downeast Air Quality Region shall consist of the Counties of Hancock and Washington; of the municipality of Stacyville, the unorganized territory of T.3, R.7, W.E.L.S., T.3, R.8, W.E.L.S. and all other municipalities and unorganized territory in Penobscot County to the south of these; and of the municipalities and unorganized territory of Blanchard Plantation, Monson, Willimantic, Bowerbank, Barnard Plantation, T.6, R.8, W.E.L.S. (Williamsburg Township), Brownville, Lake View Plantation and all other municipalities and unorganized territory in Piscataquis County to the south of these.  

4.  Aroostook Air Quality Region.  The Aroostook Air Quality Region shall consist of all municipalities and unorganized territory in Aroostook County not included within the Northwest Air Quality Region.  

5.  Northwest Maine Air Quality Region.  The Northwest Maine Air Quality Region shall consist of the municipality of Upton, the unorganized territory of C Surplus Township, C Township and all other municipalities and unorganized territory in Oxford County to the north of these; the municipalities and unorganized territory of D Township, E Township, Madrid, T.4, R.1, B.K.P., W.K.R., Kingfield and all other municipalities and unorganized territory in Franklin County to the north of these; of the municipalities and unorganized territory of Lexington Plantation, Concord Township, Bingham, Brighton Plantation and all other municipalities and unorganized territory in Somerset County to the north of these; of the municipalities and unorganized territory of Shirley, Elliottsville Plantation, T.7, R.9, W.E.L.S., T.6, R.9, W.E.L.S. (Katahdin Iron Works), T.5, R.9, W.E.L.S., T.4, R.9, W.E.L.S. and all municipalities and unorganized territory in Piscataquis County to the north of these; of the municipality of Patten, the unorganized territory of T.4, R.7, W.E.L.S., T.4, R.8, W.E.L.S., and all other municipalities and unorganized territory in Penobscot County to the north of these; and the municipality of St. Francis, the unorganized territory of T.16, R.9, W.E.L.S., T.15, R.9, W.E.L.S., T.14, R.9, W.E.L.S., T.13, R.9, W.E.L.S., T.12, R.9, W.E.L.S., T.11, R.9, W.E.L.S., and all other municipalities and unorganized territory in Aroostook County to the west of these.