Ozone depletionOzone depletion

Gregušová MichaelaGregušová MichaelaTetivová PetraTetivová Petra

What is ozone?What is ozone?

Ozone is a gas that forms in the Ozone is a gas that forms in the atmosphere when three atoms of atmosphere when three atoms of oxygen are combined (0oxygen are combined (033) )

Ozone is formed by complex Ozone is formed by complex chemical reactions between chemical reactions between volatile organic compounds volatile organic compounds (VOCs) and nitrogen oxides (VOCs) and nitrogen oxides (NOx). (NOx).

Sunlight and hot temperature Sunlight and hot temperature stimulate the chemical reactions. stimulate the chemical reactions.

volatile nestabilní

Ozone LayerOzone Layer

The "ozone layer" is defined between about 25 and 35 km. The ozone region has a very important role for life on Earth. It absorbs the UV-B radiation that is emitted by the Sun (UV-B: wavelengths between 280 and 320 nm). Only ozone has this ability to efficiently absorb the UV-B.

ability schopnost efficiently účinně

Depletion of ozoneDepletion of ozone The initial step in the depletion The initial step in the depletion

of stratospheric ozone by of stratospheric ozone by human activities is the emission human activities is the emission of ozone-depleting gases of ozone-depleting gases containing chlorine and bromine containing chlorine and bromine at Earth ’s surface.Most of these at Earth ’s surface.Most of these gases accumulate in the lower gases accumulate in the lower atmosphere. atmosphere.

When exposed to ultraviolet When exposed to ultraviolet radiation from the Sun,these radiation from the Sun,these halogen gases are converted to halogen gases are converted to more reactive gases.more reactive gases.

These and other reactive gases These and other reactive gases participate in “catalytic ”reaction participate in “catalytic ”reaction cycles that efficiently destroy cycles that efficiently destroy ozone.ozone.

Initial počáteční expose vystavit

depletion vyčerpání participate účastnit

ChloroflurocarbonsChloroflurocarbons

Chloroflurocarbons Chloroflurocarbons are the gas, that are the gas, that destroy ozone. They destroy ozone. They evolve from the spray evolve from the spray and refrigeratorsand refrigerators. .

Now is produce of flurocarbons reducing.Now is produce of flurocarbons reducing.

Ozone holeOzone hole The ozone hole is a well-The ozone hole is a well-

defined, large-scale defined, large-scale destruction of the ozone layer destruction of the ozone layer over Antarctica that occurs over Antarctica that occurs each Antarctic spring. each Antarctic spring.

The word "hole" is a The word "hole" is a misnomer; the hole is really a misnomer; the hole is really a significant thinning, or significant thinning, or reduction in ozone reduction in ozone concentrations, which results concentrations, which results in the destruction of up to in the destruction of up to 70% of the ozone normally 70% of the ozone normally found over Antarctica. found over Antarctica.

large-scale rozsáhlý

misnomer nesprávný název

thinning ztečování

significant významný

Monitoring of ozoneMonitoring of ozone

On the all world are observatory sites in which is ozone measured. Ozone is On the all world are observatory sites in which is ozone measured. Ozone is monitored from the space too.monitored from the space too.

Ozone is evaluated by the Dobson Spectophotometer.Ozone is evaluated by the Dobson Spectophotometer.

Important websitesImportant websites http://www.epa.govhttp://www.epa.gov

http://www.noaa.govhttp://www.noaa.gov

http://www.wmo.chhttp://www.wmo.ch

http://asd-www.larc.nasa.govhttp://asd-www.larc.nasa.gov

http://www.bom.gov.auhttp://www.bom.gov.au

http://www2.nature.nps.gov/airhttp://www2.nature.nps.gov/air