A student says that the hole in the ozone layer is the primary reason for the wa
ID: 1009585 • Letter: A
Question
A student says that the hole in the ozone layer is the primary reason for the warming of the Earth because it allows more energy to enter the lower atmosphere. Is this student correct? Briefly explain your answer. A council member claims that the air pollution problem in Los Angles could be solved by allowing only zero-emission vehicles to be sold and licensed there. Does this Idea make sense? Briefly explain your answer. A dietician states that the recommendation of 60 g of protein a day is misleading. She says that it Just as important to have the right kind of proteins, with the proper amino acids In them. Otherwise, even a mu Ch larger amount of protein will not be helpful. Does this statement make sense? Briefly explain your answer. An opponent of genetically modified food states that people do not want to eat food with genes in it. Does this statement make sense? Briefly explain your answer. A website states that a chemical in marijuana, THC, is a fat-soluble and should be called "vitamin M". The site says that this is justified because many of the properties of THC are similar to vitamins. Does this claim make sense? Should THS be considered a vitamin? Briefly explain your answer.Explanation / Answer
You probably don't realize that every time you step outside, ozone, a gaseous molecule of three oxygens, makes it possible for you to do so without reaping the harmful effects of the sun's radiation. This helpful ozone is found in the stratosphere, which is the atmospheric layer just above where life exists and weather occurs.
When that same gaseous ozone is found in our lower layer (called the troposphere), it is considered an air pollutant and is very harmful to human health. However, we need it in the stratosphere because even at the low concentration of 12 parts per million, ozone is so effective at absorbing the sun's UV radiation that this small amount is plenty enough to protect us on Earth.
Just how harmful is UV radiation? In humans, UV radiation causes skin cancer and cataracts. UV radiation also affects the fertility of other animals, as well as the viability of their offspring. Plants are affected by UV radiation because it affects their ability to grow and develop correctly. As you'll see later, UV radiation also influences how chemicals break down and react, and this can lead to catastrophic changes in environments and ecosystems.
CFCs Break Down Ozone
You've likely heard about the ozone hole or thinning of the ozone layer, but you may not know what causes these problems. These discoveries came about through many years of scientific research, so let's take a trip back in time to gain a better understanding of how the ozone layer has been affected by human activity.
It all began in the 1960s when scientists noticed that their measurements of ozone in the atmosphere were lower than what their models predicted they should be. The scientists believed that either naturally or artificially created chemicals were somehow depleting the ozone.
It turns out that these chemicals were something called chlorofluorocarbons, or CFCs. These are compounds used for refrigerants, fire extinguishers, and aerosol propellants. CFCs were invented in the 1920s and were originally thought to be environmentally friendly, but in fact, they break down ozone in the presence of UV radiation.
What happens is this: a chlorine molecule from the CFC is released from the compound by the UV radiation. It then reacts with an ozone molecule (O3), leaving a molecule of oxygen gas (O2) and a molecule of chlorine monoxide (ClO). The chlorine on this molecule is free to react with a single oxygen atom and then breaks away, leaving another O2 molecule and the free chlorine atom. This chlorine atom is now floating around the stratosphere, ready to break apart another ozone molecule into atmospheric oxygen, continuing the cycle until the chlorine atom breaks down. Unfortunately, the chlorine may not break down for a thousand years or more!
Early Discoveries
Ok, so now that we know how CFCs break apart ozone, let's go to the early 1970s where CFCs are being mass produced at an annual rate of one million metric tons and growing by 20% each year!
In 1974, two scientists named Sherwood Rowland and Mario Molina were able to demonstrate how CFCs were splitting ozone molecules into atmospheric oxygen and chlorine monoxide molecules, and this work earned them the 1995 Nobel Prize in chemistry. Their research helped put new policy into motion, and by 1979, the U.S. and other countries had banned CFCs in aerosol sprays, but not for other us
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.