6.2 Stratospheric ozone

Ozone

molecules that protect the Earth from harsh UV rays. They are mainly found in the strartosphere

Ozone thickness

• Thicker in the spring / thinner in the summer

• Thinner in the equator / thicker near the poles

Ozone's dynamic equilibrium

The UV rays from the sun causes the ozone molecules to break apart in order to absorb the UV rays. However, they later reform under normal conditions.

Halogen atoms

cause chemical depletion of stratospheric ozone over the globe by slowing down the rate of ozone production

CFCs

Destroys the straspheric ozone layer

Ex: Chlorofluorocarbons (CFCs or freons) - propellants in spray cans, foam, refrigerants

• Hydrochlorofluorocarbons (HCFCs) - replacements for CFCs

• Halon - fire extinguishers

• Methyl bromide - pesticides

• Nitrogen oxides - bacterial breakdown of nitrites and nitrates in the soil, supersonic aircraft

• Carbon tetrachloride - cleaning substance

Effects of UV rays

• Increase in mutation rates in DNA causing cancer

• Can cause eye cataracts

• Can damage the ability to carry out photosynthesis in plants and phytoplankton

• Reduces primary production and therefore total productivity

• Damage to immune system

Solutions to helping ozone

• recycling refrigerants

• developing alternatives to gas-blown plastics, halogenated pesticides, propellants and aerosols

• developing non-propellant alternatives.