Princeton's WordNet (3.00 / 1 vote) Rate this definition: opacity (noun) the phenomenon of not permitting the passage of electromagnetic radiation. opacity, opaqueness (noun) incomprehensibility resulting from obscurity of meaning. opacity, opaqueness (noun) the quality of being opaque to a degree; the degree to which something reduces the passage of light
Ozone is a gas that is naturally present in our atmosphere. It was first identified in laboratory experiments in 1839 and has the chemical formula O3 because an ozone molecule has three oxygen atoms attached to it.zone is a gas that is naturally present in our atmosphere. It was first identified in laboratory experiments in 1839 and has the chemical formula O3 because an ozone molecule has three oxygen atoms attached to it.
Ozone is a colorless gas found in the air we breathe. Ozone can be good or bad depending on where it occurs: Ozone occurs naturally in the Earth s upper atmosphere (the stratosphere), where it shields the Earth from the sun s ultraviolet rays. Ozone occurs naturally in the Earth s upper atmosphere (the stratosphere), where it shields the Earth from the sun s ultraviolet rays. 2  At ground-level, ozone is an air pollutant that can harm human health.