Stratospheric Ozone

difference between statospheric & tropospheric ozone

• Stratospheric ozone blocks incoming UV radiation from the sun

• Tropospheric ozone can damage respiratory tracts

description of how ozone absorbs incoming UV radiation

• ozone molecule absorbs the UV

• it breaks into in oxygen molecule (O2) and atom (O)

• these molecules can then recombine into ozone again

• dynamic equilibrium

ozone depleting substances

• refrigerants - CFCs & HFCs

• pesticides

• flame ratardants - halogens

• gas blown plastics

• aerosols

effect of UV on cells

• UV indues mutations in DNA during cell division, causing cancer

• sunburn is an inflammatory response to excessive UV

• premature skin ageing is caused by the breakdown of collagen & elastin fibres

• cataracts = clouding of the lens in the eye → blurry vision & blindness

effects of UV on biodiversity

• damage to photosynthetic organisms (phytoplankton) → reduced photosynthesis

  • also decreased nutrient cycling, effect on higher trophic levels

description of Montreal Protocol

• 1987

• 197 signatories

• emissions of ODSs fallen from 1.5m to 400k toonnes

• illegal market = significant challenge

• burden on national governments

reducing emission of ODS

• recycling refrigerants

  • collection, purification, reuse

  • green freeze tech uses propane/butane instead of ODS

• alternatives to halogenated pesticides

  • organic pest control

  • beneficial insects, neem oil

• alternatives to aerosols

  • pump action sprays

  • soap bars > shaving foam