O3 atmospheric gas

noun

1. A triatomic very reactive form of oxygen that is a bluish irritating gas of pungent odor, that is a major air pollutant in the lower atmosphere but a beneficial component of the upper atmosphere, and that is used for oxidizing, bleaching, disinfecting, and deodorizing
2. Pure and refreshing air

   "relished the ozone of morning"

noun

1. An area of the ozone layer (as near the south pole) that is seasonally depleted of ozone

noun

1. An atmospheric layer at heights of about 20 to 30 miles (32 to 48 kilometers) that is normally characterized by high ozone content which blocks most solar ultraviolet radiation from entry into the lower atmosphere

adjective

1. Not reducing the ozone in the upper atmosphere

   "an ozone-friendly product"