ozó

Ozó, commonly known as ozone, is the triatomic allotrope of oxygen with the chemical formula O3. It is a pale blue gas with a sharp odor that can be detected after electrical discharges or lightning. At ordinary temperatures it is unstable and decomposes to diatomic oxygen (O2).

In Earth's atmosphere, Ozó is formed primarily by photochemical reactions: ultraviolet radiation splits O2 into oxygen atoms, which then combine with O2 to form O3. The ozone layer resides in the stratosphere, roughly 10 to 50 kilometers above the surface, where it absorbs most of the Sun’s harmful ultraviolet radiation, protecting life from DNA damage.

Ozone also forms at lower altitudes due to human activity and natural processes. In the troposphere, reactions involving nitrogen oxides (NOx) and volatile organic compounds (VOCs) with sunlight produce Ozó, making it a major component of smog and a local air pollutant. Tropospheric Ozó poses health risks and can affect climate.

Industrial and environmental applications exploit Ozó’s strong oxidizing properties. Ozonation is used to purify drinking water, treat wastewater, and sterilize foods and medical equipment. Ozone can be generated by electrical discharges (corona discharge) or by ultraviolet lamps, depending on the application.

Measurement and impact: Ozó concentrations are reported in Dobson Units for the atmospheric column or in parts per billion by volume (ppb) for surface air. Health and environmental guidelines set exposure limits to minimize respiratory irritation and other adverse effects, while stratospheric ozone remains essential for UV protection.