The Hangover!!!

Intro

Our group consists of people who came from different background and field. We believe that we have been assigned into the same group as we all have the same passion in science, we concern about the environmental issues occurring currently and the impact of chemistry on society. We hope that we can really enjoy this course, enjoy what chemistry bring to us and “hangover” together!”

Team member

Name: Xing Hua

School: School of Electrical and Electronic Engineering

Course: Electrical and Electronic Engineering

Year: 2

Why taking this course:  Everything is made of chemicals, so as the human and all the stuff we can see in daily life. Many of the changes that we may observe are also caused by chemical reactions. Knowing some chemistry helps us to make decisions and troubleshoot problems in a more reasonable way.

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 Name: Yan Qucheng

School: School of Mechanical and Aerospace Engineering

Course: Mechanical Engineering

Year: 2

Why taking this course: Want to figure out how chemistry change our life.

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Name: Yeo Teck Yeow

School: Renaissance Engineering/ Year 1

Course: Renaissance Engineering

Year: 1

Why taking this course: Chemistry has always been a favorite subject and it would be interesting to look at it outside of usual academic content.

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Name: Yang Xiao Bin

School: School of Mechanical and Aerospace Engineering

Course: Mechanical Engineering with business minor

Year: 1

Why taking this course :Passion in chemistry and concern about the impact of chemistry on our society and raise awareness on environmental issue.

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Name: Yap Keni

School: School of Biological Sciences

Course: Biological Sciences

Year: 1

Why taking this course: It is always fun to learn how different fields of sciences are correlated and their impact on society. Besides, I believe that the team based learning carried out in this course is going to benefit me and my team members in many ways.

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Name: Xu Ziyi

School: School of Civil and Environmental engineering

Course: Maritime Studies with a second major in Business

Year: 1

Why taking this course: Interest to chemistry & concern to the society. This course is related to my another course which is also about the environment. I hope that I can apply what I’ve learned to the reality, not just some theories.

What Is The Ozone Layer?

The ozone layer refers to a region of Earth’s stratosphere which absorbs most of the Sun’s UV radiation. It contains high concentrations of ozone (O3) as compared to the other levels of the atmosphere, however, the concentration is still relatively small compared to other gases in the stratosphere. The ozone layer contains fewer than ten parts per million of ozone, whereas the average ozone concentration in Earth’s atmosphere as a whole is only about 0.3 parts per million. The ozone layer is mainly found in the lower portion of the stratosphere, approximately 20 to 30 kilometres above the earth surface. Factors such as the season and geographical location affects the thickness of the ozone layer.

The ozone layer absorbs 97–99% of the Sun‘s medium-frequency ultraviolet light which has a wavelength of about 200 nm to 315 nm, stopping potential damage to exposed life forms near the surface.

Chemical Process

Ozone in the Earth’s stratosphere is created through two processes. Firstly, when ultraviolet light strikes oxygen molecules containing two oxygen atoms (O2), it splits them into individual oxygen atoms (atomic oxygen)

O2 + ℎνuv → 2O

The atomic oxygen then combines with unbroken O2 to create ozone, O3. However, the  ozone created is chemically unstable and when ultraviolet lights strikes it, it splits into a molecule of O2 and an atom of atomic oxygen. This results in a continuing process known as the ozone-oxygen cycle.

O + O2 ↔ O3

Ozone Depletion

There are many various causes of ozone depletion.

But the largest cause would due to the reaction of ozone with free radicals such as nitric oxide (NO), nitrous oxide (N2O), hydroxyl (OH), chlorine (Cl), and bromine (Br). While most of them can be found naturally, the concentrations of chlorine, and bromine have increased significantly in recent years due to the release of large quantities of man-made organohalogen compounds, especially chlorofluorocarbons (CFCs) and bromofluorocarbons. These highly stable compounds are capable of surviving the rise to the stratosphere, where the radicals are liberated by the action of ultraviolet light. Each radical is then free to initiate and catalyze a chain reaction capable of breaking down over 100,000 ozone molecules. This results in a reduced capability of the ozone layer to absorb the ultraviolet radiation.

Other causes of ozone depletion can be natural such as large volcanic eruptions which can have an indirect effect on ozone levels. When volcanoes erupt, they produce massive clouds of ashes into the troposphere, and then they drift upward into the stratosphere. These ashes contain high concentration of bromine and chlorine. Ashes can stay in the stratosphere for about two to five years, and causing chemical reactions that can damage the ozone layer withn this period of time.

Effect of Ozone Depletion

Ozone depletion results in the amount of UV light reaching the earth surface to increase which has a varied impact on the various living things on earth. For example, in the case of humans, this leads to a rise in getting skin cancer and possibly cataracts — a clouding of the eye’s lens. As for plants, UV light results in various changes in the growth mechanisms of the plant, some possibly more beneficial than damaging. Other affected parties include the marine ecosystem, biogeochemical cycles, materials and et cetera.