Reducing Ozone Layer Hole

SYNOPSIS

The procedure in this paper approaches Ozone depletion from the Stratosphere, a layer surrounding the Earth's Atmosphere. Stratospheric ozone layer protects Planet Earth from dangerous Ultra Violet (UV) radiation (or rays) emanating from the Sun. Ozone Layer as named is made up of ozone gas; it is formed in chemical reactions involving UV rays and oxygen molecules in the stratosphere. When Sunlight breaks an oxygen molecule into two oxygen atoms, the atoms react separately with two oxygen molecules to produce two ozone molecules. These ozone molecules are dissociated by UV rays; the process of dissociation and combination in the presence of sunlight prevents planet Earth from harmful UV rays. Man use of certain gases (called ozone depleting substances) reacts with ozone molecules producing compounds that cannot prevent harmful UV rays from reaching planet Earth. Exposure to UV rays may cause damage to plants; skin cancer and cataract in humans. This paper presents a procedure on injecting oxygen gas to depleted parts of the ozone layer to replenish lost molecules and make injected oxygen join natural combination. The oxygen gas to be discharged under high pressure will join dissociation and recombination as the process that protects man from harmful UV rays. Wide as stratosphere is, this research reviews a process to add oxygen gas

to the ozone layer using aerodynamic objects directed to areas thinned.

1.0 INTRODUCTION

Ozone is the triatomic form of oxygen abundant in the atmosphere but predominant in the stratosphere, a region that is roughly between 19 and 48km above sea level. About 90% of ozone is found in the stratosphere. Most ozone resides in the lower stratosphere in what is known as the ozone layer. The remaining 10% is found in the troposphere, the lowest region of the Earth

atmosphere. [1]

The ozone layer is a protective shield, it prevents harmful Ultra Violet (UV) rays from reaching the Earth surface. UV ray have wavelengths shorter than light but longer than X-rays lying outside the visible spectrum at its violet end. UV etymology comes from the fact that the color with the highest frequency humans can see is violet, and ultra- means far beyond normal, so being undetectable to the human eye, it is ultraviolet.

Ultraviolet radiation is measured in wavelength, with units in nanometers (nm) or electron volts (eV). The amount of UV rays that reaches the ground is mainly controlled by cloud cover, pollution and amount of atmospheric ozone. If all other factors remain same, UV at the Earth's surface increases as the amount of total ozone decreases, because ozone absorbs UV radiation. [1]

Electromagnetic spectrum of UV rays can be subdivided by their wavelength range; UV-A measures between (400 nm - 315nm); UV-B measures between (315nm - 280nm); UV-C measures between (280nm – 100nm). UV-B and UV-C are screened out by the ozone layer while UV-A reaches the Earth surface. [1]

This paper presents replacing depleted parts of the ozone layer or ozone hole artificially; the Ozone hole is expected to be replaced naturally at the middle of the 21st Century, this maybe longer because certain emissions persist. This procedure posits artificial replacement; scientific and technical review will have it formed and saved for future use as necessary.

Feasibility of this procedure quite high since the method of approach tackles possible impediments. An aerodyne (heavier than-air-craft) or aerostat (lighterthan-air-craft) is expected to carry liquid oxygen to the stratosphere, because more volume of the same mass can be carried as liquid than gas. It will be discharged through a hull as gas under high pressure. Carrier aircraft should

hover around depleted area in lower stratospheric altitude where ozone depletion is observed and wind and turbulence is bearable.

2.0 THEORETICAL DEVELOPMENT

Long-term fluxes have had natural balance of ozone molecules creation and destruction in the stratosphere; with reduced use of ozone depleting substances by man, the ozone hole will not fully repair itself until the middle of the 21st Century. This is many years away even as effects of harmful UV rays are seen. [2]

The photochemical process leading to creation and destruction of ozone molecules in the ozone layer favors this artificial approach. Atomic Oxygen (O), Oxygen molecule (O2) and Ozone Molecule (O3) are some allotropes of oxygen; these are structurally different forms of oxygen with different physical and chemical properties.

In the ozone layer, UV light {<240nm} dissociates an oxygen molecule to form two atoms of oxygen, these atoms separately reacts with two other oxygen molecules to form two ozone molecules. UV rays {300-210nm} dissociate ozone molecules formed in this process. The overall process of dissociation and combination in presence of UV rays makes the ozone layer protect man and his

environment from harmful UV rays. UV rays with wavelength {enclosed} are absorbed by oxygen atoms and ozone atoms preventing these harmful UV rays from getting to the Earth Surface.

Oxygen gas to be injected in depleted parts of the ozone layer will be useful in at least two ways; it can react with oxygen atoms to create more ozone molecules or can be dissociated by UV rays to form oxygen atoms that will continue in photochemical reactions described.

Ozone gas, O3 itself is unstable and dissociates to diatomic oxygen, O2 at high concentrations in about half an hour under atmospheric conditions.

2 O3 → 3 O2

Heat intensity in the stratosphere dissociates Oxygen molecule to atomic oxygen,

O2 → O + O

O2 + solar energy of wavelength less than 242nm → 2 O2

O + O2 → O3

O + O3 → 2 O2

O3 + solar energy of wavelength less than 336nm → O* + O2

O* is an exited state of oxygen. It can be de-excited through thermal collisions and become a single oxygen atom. It can be seen that light with wavelength from 336nm down will be absorbed. Only the lowest-energy UV radiation will reach the

surface. All these transformations are encapsulated in what is called the Chapman cycle. [3]

A large percentage of ozone is formed over the equator where sunshine (heat) amount are preeminent. It is transported by moving air towards the South Pole and North Pole. At high latitudes, very high amounts of ozone are found in the upper atmosphere; its thickness is subject to change with seasons and geography.

Injecting oxygen gas to ozone depleted parts in lower stratospheric altitude will mitigate the depletion. This will be noticed by re-observing the hole after time. This process can be used recover thinned ozone over Antarctica during its spring which will help reduce fractional melting of glaciers caused by increased solar intensity during that period. [4]

Ozone Depleting Substances (ODS) are chemical elements or combination of elements of natural and artificial sources; they find their way to the stratosphere and react with ozone molecules reducing them to oxygen molecules. Natural ODS have been existent for hundreds of years but have not had the summated effect artificial ODS (of the last 30-40years) have on ozone molecules in the

ozone layer. Chlorofluorocarbons (CFC's) used as refrigerants for refrigerators and propellants in aerosols are examples of artificial ODS. CFC's contain chlorine while some others contain bromine. CFC's for example, once at the stratosphere gets dissociated by sunlight releasing chlorine, Cl-, this Cl- react with ozone molecule, O3 to produce chlorine monoxide, ClO and one oxygen molecule, O2 Cl- + O3 → ClO + O2 --- equation (i) ClO + O3 → Cl- + 2 O2 --- equation (ii)

The monoxide reacts with another ozone molecule to release two oxygen molecules, 2 O2 and chlorine,Cl-; this Cl- continues to react with ozone molecules as in equation (i) and occurs thousands of times more.

This, a brief of how ozone gas is been depleted in the stratosphere, chlorine, bromine from man-made sources add to the atoms in the stratosphere making oxygen allotropes available for UV rays protection shortened.

When oxygen gas is injected as described in the next heading, it increases the total volume of oxygen in the layer. Some injected oxygen molecules will form 'new' ozone molecules by absorbing UV rays to form ozone molecules, this will add to the number of lost ozone and oxygen molecules in the stratosphere.

*O2 → O + O

O + 'O2 → O3

*O2 is one of injected oxygen molecules that is split by UV rays into single oxygen atoms; 'O2 is part of the injected oxygen molecules that reacts with already split oxygen atom to form ozone molecule.

With this, injected oxygen molecules can solely form ozone molecules without 'likely to occur' combination with already existing oxygen molecules. The artificial method for ozone recovery suggested here is workable.

3.0 EXPERIMENTAL PROCEDURE

Since space science is fast-past tertiary stage, available technology will produce desired result for this procedure. These heading present sections relevant to achieve the objective.

3.1 Oxygen Tank

Liquid Oxygen will be carried into the stratosphere but will be released as gas because more volume of oxygen is stored as liquid than as gas. The tank capacity should contain around 200m3 of liquid oxygen per aerodyne; the liquid will be made to vaporize in the next chamber before discharge as gas. It will be ejected under high pressure to trigger reactions in the stratosphere immediately.

A non-reactive pressurized gas like Nitrogen may be held above the oxygen storage tank to force the oxygen gas to a vaporization chamber before discharg. The oxygen gas will join naturally existing molecules and let natural process of creation and collapse of Ozone molecules occur as it were.

3.2 Aerodynamic use

To get to the stratosphere with a liquefied oxygen tank an aircraft will be used; examples are: airships, rotorcrafts, drone, rocket and jumbo jet. The one with little or no aftereffect to the ozone layer, large storage capacity for the oxygen tank, high altitude capability and speed will be considered.

The problem of pollution especially to that region may hamper the use of jet engine or rocket engine. This gives light to airships but altitude and load capacity questions their ability to convey the oxygen tank and discharge the gas.

Aerodynes and aerostats have their disadvantages, but a way to discharge the oxygen gas to depleted areas of the ozone layer is a novel objective; achieving it should be possible.

3.2.1 Airship

Recent developments in airship industry especially for defense systems needles airship use for this objective. Hybrid configuration used for flying High Altitude Airships and Cargo Airships gives aerostats the advantage to get this done. Airships also called blimps or dirigibles are self-propelled lighter-than-air craft with directional control surfaces or steering systems. They may also be defined

as powered, gas-filled balloon which can be steered, not requiring movement through surrounding air. They were used for transportation many years ago; they have been modernized lately for high altitude and better transport capability. [5]

Operating capability of airships used in space defense system gives it an advantage to deliver oxygen to the ozone layer. The oxygen gas to be discharged is expected to pass through a hull and should pass through it without causing critical loss of helium in the airship. The internal hull pressure will be maintained around 1-2% above surrounding air pressure.

Previously developed stratospheric airships flew at 22km where wind and turbulence is bearable. The oxygen gas will be discharged at relatively low stratospheric altitude (20-22km). The discharged oxygen cum ozone is expected go higher in the stratosphere by natural processes.

The HiSentinel Airship, a United States Army Space and Missile Defense Command project to demonstrate powered stratospheric airship at high altitudes was tested for five hours in 2005 and could carry medium weight between 9-90kg; It flew around 18km above sea level. [6]

This example presents two barriers for the ozone replacement purpose: timing (depending on the tank capacity could discharge oxygen gas in a few hours) and its load capacity.

There are cargo airships not reaching 20km that stay longer in air and carry more weight. The airship to be used will have an equipment pod; a propulsion system and a liquid oxygen tank; it is required to discharge oxygen gas at hypersonic speed, spending few hours hovering ozone depleted space.

The airship once at the desired altitude will be programmed to immediately release the gas from the chamber at high pressure to the stratosphere; this should make the airship stay there in a short time. The airship will also release gas as it comes down steadily from its maximum altitude within the stratosphere.

Airships should be designed specifically for this procedure, there maybe twin airship design that will have both fly simultaneously and are dependent to achieve this goal.

Recent technologies have hybrid airships that can fly around 26km above sea level, stay longer in air and carry more weight. With this or special purpose airships built for ozone hole recovery, Man can be at ease for harmful Ultra Violet radiation effects and also know that comparatively cheap airship will discharge oxygen and emit little or negligible pollution.

3.2.2 Unmanned Aerial Vehicle

An unmanned aerial vehicle also called Unmanned Aircraft System or drone is defined as a powered, aerial vehicle that does not carry a human operator, it uses aerodynamic forces for lift, can fly autonomously or be piloted remotely. [7]

An unmanned aerial vehicle can help deliver oxygen gas to ozone hole since existing ones have been successfully used for reconnaissance and defense discharge at stratospheric height with weight capacity far exceeding 500kg. [8]

The design, performance, flight altitude, load capacity, Integrated system and sensor packages gives a vertex mark for expected outcome for ozone recovery. This flight presents two drawbacks, cost and pollution. We are trying to recover depleted ozone in the stratosphere but taking a flight to that level that will eject some gases that may react with naturally produced ozone and further deplete them is not nice.

Tank containing liquid oxygen with weight of about 900kg can be carried by the RQ-4 Global Hawk; the Northrop Grumman RQ-4 Global Hawk was used by the United States Air Force as a surveillance aircraft; a high altitude (21km), long endurance unmanned aerial reconnaissance system with an integrated sensor suite that provides military field commanders with high resolution, near real-time imagery of large geographic areas. [9]

A more recent Unmanned Aircraft is the Boeing X-37B, operated by the United States Air Force for space experimentation, risk reduction and a concept of operations development for reusable space vehicle technologies. It can carry a reasonable amount of load and is powered by Gallium Arsenide Solar Cells with Lithium-Ion batteries. [10] No pollution fears if this aircraft is used for this research objective; It can spend desired time and more in the stratosphere, however, it is extremely expensive to build and run.

The liquid oxygen tank will be connected to a chamber where it is expected to vaporize and released under pressure through a hull; the hull will also prevent gases from space to enter the tank. High Cost remain the major demerit of UAV's for this objective, since this research is in review stage, groups may extemporize for UAV usage.

4.0 RESULTS AND DISCUSSION

Using either of the two aerodynamic systems, at the expected altitude oxygen will be discharged to places where ozone depletion has been observed. After discharge, wind is expected to carry discharged oxygen gas or oxygen cum ozone gas higher.

The airship will linger the depleted area while it discharges the gas at high pressure for immediate reaction with existing oxygen atoms or molecules. This research is not oxygen recovery, it is ozone recovery because of processes that lead to ozone molecule formation in the stratosphere, discharged oxygen will add to the total volume of oxygen at depleted places and join in reactions.

I have carried out in-depth studies for several months on this objective, it presents overly review on having a method to artificially mitigate the ozone hole. Further validation by the research community is needed to have this procedure documented and developed overtime; it will provide an available alternative to natural recovery. Except the ozone layer does not exist and there are no holes in

some parts of it, this procedure is void.

This method seek to add oxygen gas to the stratosphere not ozone gas because adding ozone gas is practically impossible because it is delivering a large volume of gas to that height. Injecting oxygen gas is not expected to upset the existing

balance, since there is a range of ozone molecules amount in the stratosphere, incoming oxygen molecules will not exceed that range.

This approach is suggested for depleted parts of the layer not everywhere in the stratosphere, discharged gas from a number of flights should protectively cover. It is also not intended to be a continuous process because when directed to depleted parts, it will recover lost ozone molecules to a good extent that season, natural recovery will definitely be continuous not artificial recovery.

Amounts of ozone are often described in terms of the thickness of ozone in a column of air that stretched from the Earth's surface to the top of the atmosphere. The most common measurement of total ozone values in the column are called Dobson's unit (DU). [1]

One DU is equal to the number of molecules of ozone that will be needed to create a layer of pure ozone 0.01millimeter thick. Typical amounts vary between 200 and 500 DU world wide. The total ozone value of the ozone hole is only 100DU. This is equivalent to a layer of pure ozone gas on the Earth Surface having a thickness of only 1millimeter. [1]

4.1 CONCLUSION

The ozone hole can be recovered artificially from the procedure detailed in this research work, as we await natural repair in time to come, we should skillfully do by having this research analyzed and developed because we have always been a prepared world.

Development in science is beyond staying at a corner of impossibility; it is with scientists, institutions and nations to use every technology, procedure and research to save our World. This research is an option for protection, further scientific and technical review will have it on hand.

APPENDIX

Global Warming

The concept of global warming became existent with observed and measured rise in temperature in the 20th Century. Global warming is usually caused by the heat trapping actions of Greenhouse Gases (GHG). GHG are heat trapping gases that helps the Earth absorb heat within the thermal infra red range. [11]

Sunlight shines on the Earth emitting radiations in all direction including infrared radiation, some of the infrared radiation passes through the atmosphere, and some is absorbed and re-emitted in all directions by GHG. The effect is to warm the Earth's surface and the lower atmosphere.

GHG in upper atmosphere is on the increase because they are emitted mostly by human activities. Examples of GHG are water vapor, carbon (IV) oxide, methane, Nitrous oxide and ozone gas. (Ozone is a Greenhouse Gas around sea level; it causes photochemical smog and reduces visibility) Some of these gases are emitted from processes like burning fossil fuel and deforestation.

Each GHG contribution to Green House effect depends on its characteristics and abundance, in the upper atmosphere. Normally without GHG, planet Earth will be colder on average than what is obtainable.

Other dangerous substances that make it to the upper atmosphere are halogens (chlorine family of element) released when sun dissociates chlorofluorocarbons compounds used in freezer, refrigerators, fire extinguishers and air conditions. These gases once at the ozone layer react with ozone molecules and form monoxides that cannot protect us from Ultra Violet (UV) radiation.

Greenhouse gases traps heat in the troposphere, a surrounding layer of the Earth Atmosphere which is up from 10km above sea level, it precedes the stratosphere. This makes fewer heat gets to the ozone layer. Additional heat will also be useful in making ozone molecule dissociate and recombine, a process that prevents harmful Ultra Violet rays. If greenhouse gases are more in the troposphere, they trap more heat than re-emit; making the stratosphere colder. Usually re-emitted heat supports ozone molecule formation and dissociation process. A colder stratosphere results in a weaker ozone layer, which can make harmful UV rays to reach the Earth Surface. Cutting and capping GHG emissions will help stay recovery.

ACKNOWLEDGEMENT

Sometimes, I believe the World belong to Scientists; not just any person involved with scientific topics; but those whose findings are contributing or will contribute progressively towards present and future change. Scientists are sincerely appreciated.

REFERENCES

1. U.S. Climate Change Science Program, (2008) Trends in Emissions of Ozone-Depleting substances, Ozone Layer Recovery and Implications for Ultra Violet Radiation Exposure. Synthesis and Assessment Product 2.4.

2. Australian Academy of Science, (2008) Enhanced Greenhouse effect – a hot international topic: nova 016 / 016 key.

3. Wilkins J, (2006) How the Earth got its ozone layer. Energy, publication of Department of Physics, Ohio State University, E01.1 .

4. McKenzie, R., B. Connor, and G. Bodeker, (1999) Increased summertime UV observed in New Zealand in response to ozone loss. Science 285 (10 September): 1709-1711.

5. John M, Introduction of Airships. Article Alley Publications 1437412_31.

6. Smith S Jr., and L. Michael, (2007) The HiSentinel Airship, presented paper at the 7th AIAA Aviation Technology, Integration and Operation (ATIO) 2nd C, Belfast, Northern Ireland.

7. Wagner. W, (1982) Lightning Bugs and other Reconnaissance Drones, Armed Forces International Journal Page XI.

8. Axe, D, (2009) Strategist: Killer Drone Level Extremist Advantage, Wired.

9. United States Air Force, (2009) RQ-4 Global Hawk, Fact Sheet by the Air combat command, Public Affairs office, Virginia Unites States Of America.

10. United States Air Force, (2010) X-37B Orbital Test Vehicle, Fact Sheet from the Office of the Secretary of the Air Force (Public Affairs), Washington, USA.

11. United States National Academy of Sciences, (2008) "Understanding and Responding to Climate Change".

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Reducing Ozone Layer Hole

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