Welcome to this week’s episode of the DOSH DISCOVERY CHANNEL.

We’ll take a flight to the stratosphere to get a glimpse of the OZONE layer. Join the flight as we look into the tremendous benefits of this part of the atmosphere.

How can it be that these things that we can hardly live without are what hurts us the most? This is the most likely question that will run through your mind when you discover how the things that make our lives more comfortable end up hurting us and our planet.

I’m talking about basic stuff like Perfumes and deodorants, Air-conditioning machines, Insecticide sprays, etc. Though these things are requirements for our daily lives, they may also be the basis for the destruction of our world.


The Earth’s atmosphere is composed of several layers. The lowest layer, the troposphere, extends from the Earth’s surface up to about 6 miles or 10 kilometers (km) in altitude. Virtually all human activities occur in the troposphere. Mt. Everest, the tallest mountain on the planet, is only about 5.6 miles (9 km) high. The next layer, the stratosphere, continues from 6 miles (10 km) to about 31 miles (50 km). Most commercial airplanes fly in the lower part of the stratosphere.

Most atmospheric ozone is concentrated in a layer in the stratosphere, about 9 to 18 miles (15 to 30 km) above the Earth’s surface (see the figure below). Ozone is a molecule that contains three oxygen atoms. At any given time, ozone molecules are constantly formed and destroyed in the stratosphere. The total amount has remained relatively stable during the decades that it has been measured.


The ozone layer in the stratosphere absorbs a portion of the radiation from the sun, preventing it from reaching the planet’s surface. Most importantly, it absorbs the portion of UV light called UVB. UVB has been linked to many harmful effects, including skin cancers, cataracts, reduced immunity to diseases and harm to some crops and marine life.

Scientists have established records spanning several decades that detail normal ozone levels during natural cycles. Ozone concentrations in the atmosphere vary naturally with sunspots, seasons, and latitude. These processes are well-understood and predictable. Each natural reduction in ozone levels has been followed by a recovery. Beginning in the 1970s, however, scientific evidence showed that the ozone shield was being depleted well beyond natural processes


When chlorine and bromine atoms come into contact with ozone in the stratosphere, they destroy ozone molecules. One chlorine atom can destroy over 100,000 ozone molecules before it is removed from the stratosphere. Ozone can be destroyed more quickly than it is naturally created.

Some compounds release chlorine or bromine when they are exposed to intense UV light in the stratosphere. These compounds contribute to ozone depletion and are called ozone-depleting substances (ODS). ODS that release chlorine include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), carbon tetrachloride, and methyl chloroform.

Sources of CFC

a) Refrigerators and air conditioners – Refrigerants are the most common emitter of CFC. If the coolant used in refrigerators, air conditioners, and cars, is not properly disposed of it will leak CFCs into the atmosphere. Either the coolant will evaporate or get into the soil, contaminating both with CFC.

b) Aircraft halon – Aviation industries in some countries are still using fire suppression systems with halon. Also, it is a coolant having CFC in it. Conclusive measures should be followed to dispose of this dangerous chemical or to recycle the material.

c) Aerosol sprays – Aerosol cans and propellant liquid use gases containing CFCs. Slowly this industry is using less harmful hydrocarbon. However, CFCs have a life span of 50 to 100 years, still having an impact on the damage done in previous decades.

d) Rogue CFCs – Without any proper dumping method and recycling process, the older and obsolete Refrigerants and aerosol cans are thrown in the open environment. CFCs leak from them further contaminating the environment.


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May 2024