Ozone is a gas composed of three oxygen atoms and occurs both near the Earth’s surface (ground-level or tropospheric ozone) and high up in the stratosphere. Ground-level ozone is a harmful air pollutant formed by chemical reactions between nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of sunlight, often emitted from vehicle exhaust, industrial emissions, and household products like paints and solvents. This ozone is a major component of smog and can cause respiratory problems and environmental damage. In contrast, stratospheric ozone, located 6 to 25 miles above the Earth, forms the ozone layer that protects life by absorbing 95-99% of the sun’s harmful ultraviolet radiation. While ground-level ozone contributes to air pollution and is detrimental to health, stratospheric ozone plays a vital role in regulating Earth’s climate and protecting organisms from UV damage.
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