18 March – Minutes

Location: South Spine 2 Tutorial Room 97

Time: 1630

Duration of the meeting: 1hr 30mins

Team members who attended: ALL

Topic discussed: Video, updating of blogs

Tasks to be done before the next meeting :

1. Finish up blog entries

2. Edit Video

References

Brian Dunbar, Shelley Canright (2009) ‘Ozone: What is it, and why do we care about it?’ Retrieved on 15 March, 2015 from  http://www.nasa.gov/audience/foreducators/postsecondary/features/F_Ozone_prt.htm

Caroline Tran, Dan Chong , Anne Keith, Jordan Shively (n.d.) ‘Depletion of the Ozone Layer’ Retrieved on 15 March, 2015 from http://chemwiki.ucdavis.edu/Physical_Chemistry/Kinetics/Case_Studies%3A_Kinetics/Depletion_of_the_Ozone_Layer

Charles Welch (n.d.) ‘The Ozone Hole’ Retrieved on 18 March, 2015 from www.theozonehole.com

Freddy (n.d.) ‘Layers of the atmosphere’ Retrieved on 15 March, 2015 from http://clccharter.org/freddy1/weather/atmosphere/layers.html

H. S. Rzepa (2015) ‘On the overall reaction of Ozone decomposition catalysed by chlorine radical’ Retrieved on 24 March, 2015 from  http://www.ch.ic.ac.uk/rzepa/mim/environmental/html/cfc.htm

Larry West (n.d.) ‘Ozone: The Good and Bad of Ozone’ Retrieved on 18 March, 2015 from  http://environment.about.com/od/ozonedepletion/a/whatisozone.html

Lee Soo Ying (n.d.) CM1041 Kinetics Notes ‘On the catalysed and uncatalysed reaction energy diagram’ Retrieved on 24 March, 2015

NASA. (June 2000)’Studying Earth’s Environment From Space’ Retrieved on 6 March, 2015 from  http://www.ccpo.odu.edu/SEES/index.html.

Unknown (n.d.) ‘Ozone layer’ Retrieved on 15 March, 2015 from http://en.wikipedia.org/wiki/Ozone_layer

Unknown (2010) ‘ The Ozone Layer’ Retrieved on 15th February, 2015 from http://eschooltoday.com/ozone-depletion/where-is-the-ozone-layer.html

Unknown (n.d.) ‘How Ozone protect us’ Retrieved on 11 March, 2015 from http://earth.rice.edu/mtpe/atmo/atmosphere/topics/ozone/o3.html

Unknown (n.d.) ‘The Impacts of Ozone Depletion’ Retrieved on 17 March, 2015 from http://www.bcairquality.ca/101/ozone-depletion-impacts.html

Unknown (2011) ‘ Health and Environmental Effects of Ozone Layer Depletion’ Retrieved on 17 March, 2015 from  http://www.epa.gov/spdpublc/science/effects/index.html

Unknown (n.d.) ‘Ozone Depletion’ Retrieved on 17 March, 2015 from http://en.wikipedia.org/wiki/Ozone_depletion#Increased_UV

Unknown (n.d.) ‘Ozone Depletion’ Retrieved on 15 March, 2015 from http://www.ozone-hole.org.uk/09.php

Unknown (n.d.) ‘Ozone Depletion’ Retrieved on 17 March, 2015 from http://www.ozone-hole.org.uk/14.php

Unknown (n.d.) ‘Ozone Depletion’ Retrieved on 17 March, 2015 from http://www.ozone-hole.org.uk/16.php

Unknown (2010) ‘ Ozone Layer’ Retrieved on 11 March, 2015 from  https://www.ec.gc.ca/ozone/default.asp?lang=En&n=DB5CBDE6-1

Unknown (n.d.) ‘Ozone-oxygen cycle’ Retrieved on 6 March, 2015 from http://en.wikipedia.org/wiki/Ozone-oxygen_cycle

 

How does the destuction of the ozone layer affect Singapore?

Sea level rise

As a low-lying island, the rise in sea level poses the most immediate threat to Singapore. Much of our nation lies only 15 m above the mean sea level, with about 30% of our island being less than 5 m above the mean sea level.

Water resources

An increase in the intensity of weather variability could present significant challenges to the management of our water resources. Periods of drought can affect the reliability of Singapore’s water supply, while sudden episodes of intense rainfall could overwhelm our drainage system and lead to flash floods.
Biodiversity and greenery

A mean temperature increase of 1.5°C to 2.5°C could affect the natural diversity of Singapore’s plants and animals at risk, as this alters our ecosystem’s natural processes such as soil formation, nutrient storage and pollution absorption.

Effect on public health

Singapore is situated in a region where vector-borne diseases are endemic. Most cases of vector-borne diseases like dengue are observed during warmer periods of the year. In addition, frequent and severe instances of warm weather may lead to more occurrences of heat stress and discomfort among the elderly and sick.
Urban heat island effect

Urban areas tend to be warmer due to the replacement of natural land cover with buildings and other infrastructure that retain or produce heat. Higher annual temperatures can also lead to heat stress as well as greater use of air-conditioning, increasing Singapore’s energy demands. This in turn results in higher domestic carbon emissions.
Food security

The effects of climate change, such as intense storms, flooding and prolonged droughts, are one of the trends threatening global food security. In Singapore, we are particularly vulnerable to fluctuations in global food supply and prices, as we import more than 90% of our food.

Effects of CFC on Ozone Layer

HI!! I would like to bring to your attention how your air conditioners are stabbing you on the back with the CFCs produced.

Giving you a rough idea before going into the details, CFC catalyses the decomposition of Ozone to diatomic Oxygen. Hence, the amount of Ozone decreases.

Screen Shot 2015-03-24 at 12.38.54 am

CFCs, are molecules in which all four atoms attached to one central carbon are Chlorines and Fluorines. The catalytic properties is due to the Chlorine atom present in the one carbon molecule. When “activated”, CFCs exerts their sinister reactions.

CFCs can be activated by UV light. When shined with UV, which the stratosphere has high exposure to, CFCs undergo a reaction to produce a Chlorine Radical, an atom with an unpaired electron.

Screen Shot 2015-03-24 at 1.01.00 am

 

This is known as the Initiation Step, which is UV-induced.

Then, the chlorine radical acts as the catalyst for the destruction of Ozone. As the radical acts as a catalyst, the radical is not consumed  and is able to catalyse more ozone destruction reactions.

Screen Shot 2015-03-24 at 1.03.33 am

 

This is known as the Propagation Step, which can go on and on untill several millions of ozone molecules are destroyed. However, two chlorine radicals can react to terminate this propagation, hence, known as the Termination Step.

Hence the overall reaction is depicted as follow.

Screen Shot 2015-03-24 at 1.29.08 am

To summarise, the chlorine radical provides an alternative pathway for the degradation of Ozone. If uncatalysed, the conversion of ozone molecules to diatomic molecules requires a high input of energy (activation energy) which makes the reaction very very very slow. Below shows the two step pathway that the chlorine radical provides to reduce the energy required to kick start the reaction.

Screen Shot 2015-03-24 at 1.37.37 am

 

 

Hope you enjoyed. Thanks 🙂

References:

H. S. Rzepa (2015) ‘On the overall reaction of Ozone decomposition catalysed by chlorine radical’ Retrieved on 24 March, 2015 from  http://www.ch.ic.ac.uk/rzepa/mim/environmental/html/cfc.htm

Lee Soo Ying (n.d.) CM1041 Kinetics Notes ‘On the catalysed and uncatalysed reaction energy diagram’ Retrieved on 24 March, 2015

 

Positive effects of Ozone

Although ozone is an highly reactive form of oxygen and unstable, there are some benefits that it is able to provide us with. Below of some positive effects of the ozone.

 Small concentrations of ozone occurs naturally in the stratosphere. which is part of the Earth’s upper atmosphere. At that level, ozone layer do provide us to a certain level of protection, as seen in the diagram below.

 

By absorbing those ultraviolet radiation, it can help block to certain extent those harmful UV radiation that causes skin cancer, damage crops, destroy some type of marine life  and cataracts.

References:

Charles Welch (n.d.) ‘The Ozone Hole’ Retrieved on 18 March, 2015 from www.theozonehole.com

Larry West (n.d.) ‘Ozone: The Good and Bad of Ozone’ Retrieved on 18 March, 2015 from  http://environment.about.com/od/ozonedepletion/a/whatisozone.html

13feb -minutes

Location:  Whatsapp chat

Time: 20 00

Duration of the meeting: 20mins

Team members who attended: ALL

Topics discussed: Topic videos ,updating of blogs etc.

Tasks to be done before the next meeting:  

1.Research on sub topics and update blog.

 

03 cycle, equations involved and factors affecting the cycle (Amelia)

Effects of  ozone depletion (YatYan)

 

2. Date to meet up as a group for video making: 18 /03/15 after lecture.

3. Style of video we are intending to make: khan academy style. Narration /explanation and drawing on a white screen.

Implications to society

The world is currently still facing the problem of ozone depletion. Though there are efforts trying to reduce the use of CFCs and other contributory substances, we cannot ignore the serious impact of ozone depletion on the society.

ozoneOn the whole, impact of ozone depletion can be categorize into 2 types: Environmental effects and health effects. The ozone screen/layer is responsible for absorbing UVB ultraviolet light from the sun. Hence, with ozone depletion, the UVB level on the whole reaching earth surface increased.

Health Effects:

Prolonged exposure to the UV rays can cause sun burn, skin cancer, premature skin aging in both humans and animals.  It can weakens the human immune system according to some research, a probable cause to skin cancer. Furthermore, given too much exposure of the eyes to UV rays could lead to cataracts, blindness or other eye diseases.

In addition, the increase in surface UV leads to increase tropospheric ozone. As ozone is very toxic and hence could badly affect the health of those with respiratory issues.

Environmental Effects:

Plants are affected by the increased UV radiation, especially rice crops. The increase in UV radiation prevents nitrogen from retaining at the roots, thus affecting its growth rate.

Marine life is also affected by the increase in UV radiation. Organisms like Phytoplankton  is  threatened by the increase in UV radiation and the supply of such basic food for marine creatures is hence greatly reduced. That in turn affects other marine creatures like fishes to have lack in food supply. Size of those population of marine animals that consumes the planktons are directly affected.

Another implication that ozone depletion brings about is the increase degradation of materials. Materials that are composed of polymers are affected by the solar UV radiation. It accelerates the breakdown of such materials and may leads to such materials being less durable and usable in the future.

References:

Unknown (n.d.) ‘The Impacts of Ozone Depletion’ Retrieved on 17 March, 2015 from http://www.bcairquality.ca/101/ozone-depletion-impacts.html

Unknown (2011) ‘ Health and Environmental Effects of Ozone Layer Depletion’ Retrieved on 17 March, 2015 from  http://www.epa.gov/spdpublc/science/effects/index.html

Unknown (n.d.) ‘Ozone Depletion’ Retrieved on 17 March, 2015 from http://en.wikipedia.org/wiki/Ozone_depletion#Increased_UV

Unknown (n.d.) ‘Ozone Depletion’ Retrieved on 17 March, 2015 from http://www.ozone-hole.org.uk/14.php

Unknown (n.d.) ‘Ozone Depletion’ Retrieved on 17 March, 2015 from http://www.ozone-hole.org.uk/16.php

Factors affecting Chapman Cycle

Factors that imbalance the Chapman cycle can lead to ozone depletion such as:

1. The Release of Free Radicals

As ozone and free oxygen atoms are highly unstable, they react very easily with nitrogen, hydrogen, chlorine and bromine compounds which  are found naturally in Earth’s atmosphere.

2. The uses of Ozone-depleting substances (ODS)

ODS are very stable, nontoxic and environmentally safe in the lower atmosphere. However, their very stability allows them to float up, intact, to the stratosphere. Chlorofluorocarbon, Methyl Chloroform, Halons, Carbon Tetrachloride and hydrofluorocarbon are common OCD.

Molecules that are no longer shielded from ultraviolet radiation by the ozone layer will break up and release chlorine atoms which reacts with the ozone.

3. Natural influences on Stratospheric Ozone

Sunspots, Stratospheric winds and Volcanic Eruptions are Natural variations which influence the amount of ozone in the upper atmosphere.

The effect caused by solar activity and Atmospheric Winds does not have a large impact. Large eruptions can potentially inject significant quantities of chlorine. Majority of volcanic eruptions are too weak to reach the stratosphere remains in the troposphere where it is quickly dissolved and washed out by rain.

 

Resources:

Brian Dunbar, Shelley Canright (2009) ‘Ozone: What is it, and why do we care about it?’ Retrieved on 15 March, 2015 from  http://www.nasa.gov/audience/foreducators/postsecondary/features/F_Ozone_prt.htm

Caroline Tran, Dan Chong , Anne Keith, Jordan Shively (n.d.) ‘Depletion of the Ozone Layer’ Retrieved on 15 March, 2015 from   http://chemwiki.ucdavis.edu/Physical_Chemistry/Kinetics/Case_Studies%3A_Kinetics/Depletion_of_the_Ozone_Layer

Unknown (n.d.) ‘Ozone Depletion’ Retrieved on 15 March, 2015 from http://www.ozone-hole.org.uk/09.php

Importance of Ozone

The ozone layer in the atmosphere protects living organisms on Earth from harmful ultraviolet (UV) rays from the Sun. It acts as a shield to absorb the UV rays, and keep them from doing damage at the Earth’s surface.

Reference:

Unknown (n.d.) ‘How Ozone protect us’ Retrieved on 11 March, 2015 from http://earth.rice.edu/mtpe/atmo/atmosphere/topics/ozone/o3.html

AY2014/15 Sem 2

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