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The Ozone Layer and CFCs Presentation

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Doricah kerubo

on 11 February 2016

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Transcript of The Ozone Layer and CFCs Presentation

How do Chemical Reactions deplete the natural Ozone Cycle?
Chlorofluorocarbons and other ODSs are non-metal molecules composed of covalent bonds.
Normally stable at sea level in the troposphere under benign UV-A and visible light
In the stratosphere the stronger sun radiation reacts with these gas molecules
They decompose, forming free radical chlorine or bromine atoms
One chlorine catalyst can destroy 100 000s of ozone molecules

How have we
taken action to
reduce the Ozone Hole?
CFC's and other ODSs phased out since 1987 (Montreal Protocol agreed with by 196 nations by 2010)
Were replaced by HCFCs, now by HFCs
By using Eco-friendly household or other cleaning agents.
Limit private vehicle driving to decrease vehicle emissions.
Spreading awareness
This is what
Earth would be like
without the Ozone Layer
What is the Ozone Layer?
The Chapman Cycle
Natural Ozone Creation and Destruction
The Different Types of UV Radiation
What are CFCs?
Chlorofluorocarbons (or CFCs) are one of a number of Ozone Depleting Substances (ODS) which were used:
as propellants
coolants in fridges
in air conditioning systems
in fire extinguishers
for blowing foam plastics

Other examples of ODSs are
Hydrochlorofluorocarbons (HCFCs)
Halons (Bromine gases)
Carbon tetrachloride
Hydrofluorocarbons (HFCs)
How do the CFCs do it?
A short quiz

Why do we like sunlight?
Ozone Layer,
located in the
prevents harmful short wave-length UV radiation from reaching the earth in the
It is a defence system from solar radiation
Varies in % seasonally and is thicker at the equator than the poles
Helps in balancing the ecosystem by preventing too much UV-B reaching living organisms
Good v Bad Ozone
and CFCs
Rowie Christopher, Doricah Kerubo, Lydia Trafford January 2016
Increased exposure to harmful UV
On humans
Damage to genetic materials in the cells
Increase in cataracts in humans
Higher incidence of skin cancers
On the environment
Reduction of plankton (micro marine life) in oceans
Destruction of plants including crops
Excessive UV-B inhibits the growth of green plants
It can lead to development of cancer and birth defects
in animals

What are the effects of the pollution?
Blue areas show thinning of the ozone layer over Antarctica since 1982
What is ozone?
Why is it important?
How can you protect yourself from UV-B?
How can you help protect the Ozone Layer?
The Earth is also surrounded by a
Magnetic Field.
This acts like an umbrella, deflecting the bulk of the strong solar wind and cosmic rays from stripping away our atmsphere.
It has decreased by 10% over the last 150 years, a natural process, that might be contributing to declining of stratospheric ozone
What is Ozone?
Ozone Concentration vs. Height (Ajavon, et al., 2007)
What the Ozone Layer filters out
The Ozone Hole
Polar Stratospheric Clouds
The extreme cold and high altitude create
perfect conditions for Ozone depletion via Cl and ClO as well as other ODSs
Ozone hole 2014

Twenty Questions and Answers about the Ozone Layer. Available from <http://ozone.unep.org/Assessment_Panels/SAP/Scientific_Assessment_2010/SAP-2010-FAQs-update.pdf >[27 Jan 2016]

ESA, Netherlands, Earth’s magnetic field provides vital protection, Astronomy magazine, 13 March, 2012. Available from <http://www.astronomy.com/news/2012/03/earths-magnetic-field-provides-vital-protection> [27 Jan 2016]

Is Ultraviolet light harmful? Understanding UV-C – Lumalier UV Surface and Air Disinfection. Available from <http://www.lumalier.com/why-uv-works/understanding-uv-c>[27 Jan 2016]

Stallard, B., Our Ozone Hole is Still Shrinking, says NASA, Nature World News, 14 Oct, 2014. Available from <http://www.natureworldnews.com/articles/9992/20141031/ozone-hole-still-shrinking-nasa.htm> [27 Jan 2016]

Lewis, R. and Evans, W., Ozone Layer Depletion - Environmental Chemistry - Atmospheric Pollution, Chemistry, 4 edition, Palgrave Foundations 2011, pp.408

BBC Bitesize: Stable Earth -The ozone layer, 6 Dec 2015. Available from <http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway/home_energy/stable_earthrev3.shtml> [accessed 7 Dec 2015]

CFF Conserve Energy Future: What is Ozone Layer, 7 Dec 2015. Available from <http://www.conserve-energy-future.com/ozone-layer-and-causes-of-ozone-depletion.php> [Accessed 7 Dec 2015]

HerrPingui, When CFCs meet Ozone, YouTube, 25 April 2008. Available from < [7 Dec 2015]

Nasa Goddard, Why is the Ozone Hole Getting Smaller? Nov 7, 2014. Available from < [7 Dec 2015]

Angelica Laurnte, CFCs and Ozone Depletion, YouTube, Oct 13, 2014. Available from <https://www.youtube.com/watch?v=a17IvL12bDo>[11 Jan, 2016]

The Ozone Hole - Ask the Scientist, Frequently Asked Questions. Available from <http://www.theozonehole.com/askthescientist.htm>
<http://www.theozonehole.com/>[16 Dec, 2015]

Goddard Media Studios, Big Ozone Holes Headed for Extinction by 2040, NASA, May 6, 2015. Available from <https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11781> [16 Dec, 2015]
Full transcript