SECTION 1.  Chapter 270 of the of the General Laws, as appearing in the 2010 official edition, is hereby amended by inserting after section 22 the following section:-

As used in this section, the following words shall have the following meanings:

(a) “Common area” means every enclosed area of a senior housing building that residents of more than one unit of that building are entitled to enter or use, including but not limited to, halls, lobbies and courtyards, elevators and stairs, community rooms, gym facilities, swimming pool areas, parking garages, shared restrooms, shared laundry rooms, shared cooking areas, and shared eating areas.

(b) “Inhabitant” means any person legally entitled to reside in a unit.

(c) “Senior housing building” means any residential property restricted to adults aged 65 and older that contains more than 3 units in a single building.

(d) “Unit” means a personal dwelling space, even where lacking cooking facilities or private plumbing facilities, and includes any associated exclusive use area.

(e) “Smoking” means the lighting of a cigar, cigarette, pipe or other tobacco product or possessing a lighted cigar, cigarette, pipe or other tobacco or non-tobacco product designed to be combusted and inhaled.

SECTION 2.  When an inhabitant of a senior housing building uses oxygen for medical purposes, smoking is prohibited in all units and common areas.