What happens to CFCs in the stratosphere?
Once in the atmosphere, CFCs drift slowly upward to the stratosphere, where they are broken up by ultraviolet radiation, releasing chlorine atoms, which are able to destroy ozone molecules. The seasons have an impact on the Antarctic ozone hole.
Why CFC can be found in the stratosphere?
CFCs reach the stratosphere because the Earth’s atmosphere is always in motion and mixes the chemicals added into it. Gases such as CFCs that do not dissolve in water and that are relatively unreactive in the lower atmosphere are mixed relatively quickly and therefore reach the stratosphere regardless of their weight.
Which layer of the atmosphere has CFCs?
ozone layer
The ozone layer, our Earth’s sunscreen, absorbs about 98 percent of this devastating UV light. The ozone layer is getting thinner. Chemicals called chlorofluorocarbons (CFCs) are a reason we have a thinning ozone layer. A chlorofluorocarbon (CFC) is a molecule that contains the elements carbon, chlorine, and fluorine.
How will CFCs interact with solar radiation in the stratosphere?
When a CFC molecule reaches the stratosphere, it eventually absorbs UV radiation, causing it to decompose and release its chlorine atoms.
Why CFCs are considered as pollutants?
The chlorofluorocarbons release chlorine atoms when they break down in the presence of UV radiations and thus deplete the ozone layer. The chlorine released reacts with ozone molecules and forms oxygen which reduces the ozone quantity causing its depletion. This is the reason why CFCs are considered as pollutants.
How do CFCs enter the atmosphere?
The most common emitter of CFCs are refrigerants, particularly those used after the 1930s. When the coolant used in old refrigerators, cars, air conditioners and other machines is not properly disposed of, it leaks CFCs into the atmosphere as liquids evaporate or work their way into the soil.
What is the strongest evidence that CFCs are in the stratosphere?
Air samples taken in the stratosphere provide the strongest evidence that it is refrigerant chemicals that are destroying the ozone. Air samples of the stratosphere contain significantly increased amounts of CFCs and HCFCs, as well as carbon monoxide.
How long can CFCs stay in the stratosphere?
These compounds are chemically inert and may remain in the atmosphere for 40-150 years, and concentrations can be expected to reach 10 to 30 times present levels.
How are CFCs added in atmosphere?
Chlorofluorocarbons (CFCs) are anthropogenic compounds that have been released into the atmosphere since the 1930s in various applications such as in air-conditioning, refrigeration, blowing agents in foams, insulations and packing materials, propellants in aerosol cans, and as solvents.
How do CFCs pollute the atmosphere?
Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and halons destroy the earth’s protective ozone layer, which shields the earth from harmful ultraviolet (UV-B) rays generated from the sun. CFCs and HCFCs also warm the lower atmosphere of the earth, changing global climate.
How long do CFCs stay in the stratosphere?
The environmental concern for CFCs follows from their long atmospheric lifetime (55 years for CFC-11 and 140 years for CFC-12, CCl2F2)9 which limits our ability to reduce their abundance in the atmosphere and associated future ozone loss.
How do CFCs affect ozone production in the stratosphere?
Gaseous CFCs can deplete the ozone layer when they slowly rise into the stratosphere, are broken down by strong ultraviolet radiation, release chlorine atoms, and then react with ozone molecules.
Why do CFCs diffuse into the stratosphere?
CFCs’ lack of reactivity gives them a lifespan that can exceed 100 years, giving them time to diffuse into the upper stratosphere. Once in the stratosphere, the sun’s ultraviolet radiation is strong enough to cause the homolytic cleavage of the C-Cl bond.
Are CFCs still a problem in the atmosphere?
Even though the production of CFCs was restricted or eliminated by an international treaty in 1987, the long lifetime of these molecules in the troposphere and their slow migration to the stratosphere means that they will be a problem for many more years. Reactions of Chlorine Atom
Do CFCs destroy ozone?
Rowland, a professor of chemistry at the University of California, Irvine, and Molina, a postdoctoral fellow in Rowland’s laboratory, had shown that chlorofluorocarbons—CFCs—could destroy ozone, a molecule made up of three oxygen atoms, O 3, in Earth’s stratosphere.
Do CFCs react with hydroxyl radicals in the stratosphere?
CFCs in the Stratosphere Photolysis Chlorofluorocarbons, because they don’t have any C-H bonds, don’t react with hydroxyl radical in the troposphere. They have a very long lifetime in the troposphere and eventually migrate to the stratosphere.