Please Name 4 major sources of chlorofluorocarbons.
carbon dioxide is produced mainly from six processes:
1. From combustion of fossil fuels and wood;
2. As a by-product of hydrogen production plants, where methane is converted to CO2;
3. As a by-product of fermentation of sugar in the brewing of beer, whisky and other alcoholic beverages;
4. From thermal decomposition of limestone, CaCO3, in the manufacture of lime, CaO;
5. As a by-product of sodium phosphate manufacture;
6. Directly from natural carbon dioxide springs, where it is produced by the action of acidified water on limestone or dolomite.
Release to the atmosphere is primarily from CFC-containing aerosols, refrigeration equipment and some foams. There are no natural sources of CFCs.
Global environmental effects
The major impacts of CFCs occur at the global level. CFCs gasses have both global warming impacts and ozone depleting effects. Although total emissions of CFCs are relatively small, they have a very high Global Warming Potential (GWP). CFCs are primarily responsible for depletion of the Earth's stratospheric ozone layer, which shields life on earth form harmful ultraviolet radiation. The chemical stability of CFCs allows them to reach the stratosphere, where intense ultraviolet radiation causes them to break apart and release chlorine, which in turn reacts with ozone. The result is a reduction in stratospheric ozone, which protects the earth from the sun's ultraviolet rays. CFCs also absorb reflected infrared radiation and they are potent 'greenhouse gases' with long lifetimes.
Possible health concerns
Excessive exposure to some chlorofluorocarbons may affect the brain, eye, heart, kidney, liver, pancreas, reproductive system and skin. The Environment Agency aims to ensure that environmental exposures are too low to harm human health.
sources of ozone
Ground-level ozone is not emitted directly into the atmosphere. It results from photochemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOCs) in the presence of sunlight. High levels typically occur from May to September, between noon and early evening.
effects of ozone
O3 irritates the respiratory tract and eyes. Exposure to high levels of O3 results in chest tightness, coughing and wheezing. People with respiratory and heart problems are at a higher risk. Ozone has been linked to increased hospital admissions and premature death. Ozone causes agricultural crop loss each year in Ontario and noticeable leaf damage in many crops, garden plants and trees.
A type of air pollution causes acid rain. When people burn fossil fuels like oil and coal, the smoke has a chemical in it called sulfur dioxide. When the sulfur dioxide gas comes into contact with water droplets in the atmosphere, it changes into sulfuric acid. This is one of the ways acid rain forms. Volcanoes also give off sulfur dioxide gas.
Sulfuric acid isn't all bad, though. People use this acid in lots of ways. Batteries in cars have sulfuric acid in them. Some drain cleaners do too. Humans make more than 100 million tons of sulfuric acid each year!
The hot atmosphere of the planet Venus has sulfuric acid in it. That makes it really hard to build spacecraft that can last very long in the atmosphere of Venus.
Chlorofluorocarbons are compounds containing the elements chlorine, fluorine and carbon. CFC's are known by the DuPont brand name Freon. There are no recognized natural sources of CFC's, and their manufacture has largely been phased out under the Montreal Protocol in response to destruction of the stratospheric ozone layer. Sources of CFC's may be or have been some (not all): 1. spray can propellants (aerosols) 2. cleaning solvents 3. insulating materials 4. foams 5. refrigerants 6. air conditioning ("freon" gas) 7. electrical components