6.2: Stratospheric ozone Flashcards
outline the potentially harmful effects of ultraviolet radiation on living tissue?
damages human tissue, increasing the incidents of cataracts, mutation during cell division, skin cancer and suppression of the immune system.
Damages to photosynthetic organisms, espseically phytoplancton.
Explain how increased levels of UV radiation can influence biological productivity?
UV radiation destroys chromophils which reduce rate of photosynthesis. Phytoplankton which live in the upper layer of water are the most affected.
As phytoplankton is consumbed by zooplankton their numbers are depleted- reducing overall productivity.
With reference to three types of UV radiation, outline how the frequency of the radiation effects is potential to cause harm to living tissue.
UVa- low energy, long wave leant, least harmfull.
UVb-
UVc- high energy, shortest wave leanth, most harmfull.
state why the stratospheric ozone is said to exist in a dynamic equilibrium?
ozone formation and break down is a natural process. Ozone is contantly pocussed by sunlight destoryed by Nox in startosphere.
draw a diagram to summarise the natural formation and destruction of ozone in the presens of UV radiation in the stratosphere.
Answer in hot girl atmosphere.
CFCs can delpete ozone levles. List uses of CFCs?
manafacturing of aresol sprays, foams, packaging materialsand pestidides.
There is a diagram in pink on hotgirl atmosphere, what are the thre epoin you need to take away from this diagram?
1) chlorofluorocarbons realase chlorine atoms when exposed to UV radiation in the atmosphere.
2) The chlorine atom interacts with ozone and breaks it down to molecular oxygen (and produces CIO)
3) CIO can then be split up to regenerate a chlorine attom. This can continue to deplete of stratospheric ozone.
State the effect of CFC relase on the amound of UV radiation reachig living things?
More Uv reaches earth and effects more tissue and productivity.
explain the formation of the ‘hole’ in the ozone layer?
the amount of Ozon in the atmosphere above Antartica decreases significantly during spring (september and October) and increases again in november.
Appart from the annual cycle during the last 30 years the minimum thickness of the ozone layor has reduced dirastically and recovary has been taking longer hence the use of the word ‘hole’ .
Ozone depeletion is the resuult of air pollution by chemical which are mostly human made.
what are some ozone delpeting substanses and what are their sources?
CFCs- propellants in spray cans
HCFCs- and alternatiev to CFCs, less harmfull but still harmfull.
Halons - fire extinguiers
Methyl Bromide- pesticide
Nox- bacterial breakdown of nitrates, high lying supper soinic aircrafts.
what methods can we employ to reduce ozone delpeting substanses?
ALTERING HUMAN ACTIVITY- replace gas blown plastics, replace aerosols with pump action sprays.
REGULATING POLUTANTS AT THE SOURCE- legistate the recovary and recycling of CFC from refridirators and AC units. Capture CFCs from scape cair AC units.
CLEAN UP AND RESTORATION- add ozone to or remove chlorine from stratosphere (however this is not practical).
talk about a group which has made a diffrence in the ozone health and how they did it?
UNEP has played a key role in providing information, creating and evalyating international agreements for the protection of stratospheric ozone.
in 1987 UNEP bought together 24 countires the initial montereal protocol on substanses that delpete the ozone layor. by 2024, 197 countires have signed the protocol. The sucess of this has lead to a reduced phasing out scedual. Productions of ODSs fell from 1.8 million tonnes in 1987 to just 45000 tonnes in 2010.
How is the ozone doing today?
ozone layer is slowly but noticeably healing at a pace that would fully mend the hole over Antarctica in about 43 years, a new United Nations report says.
The progress is slow, according to the report presented Monday at the American Meteorological Society convention in Denver.
The global average amount of ozone 30 kilometers high in the atmosphere won’t be back to 1980 pre-thinning levels until about 2040, the report said.
can youu expand on the montereal protocol on a socitital levle?
The protocol raised public awarness of the use of CFCs and provided an incentive four countires to find an alternative.
Tecnologiy has been transfered to LEDCs to allow them to replace ODSs, but some sutabsces still used are ozone depleting such as HCFCs. some HCFCs have been replaced by HFCs but these are powerfull greenhouse gasses.
what are some trubbled that persist even after the monertreal protocol?
it is harder for LEDC to impliment changes
the second hand applicance market means that old fidges are still in curculation.
it is a protocol which is dependant on goverments being willing to comply.
the long life of the chemicals in the atmosphere means that damage will continue for some time- until 2100.
