Carbon Monoxide

Posted September 12th, 2011 by

Carbon MonoxideCarbon monoxide (CO), also called carbonous oxide, is a colorless, odorless, and tasteless gas which is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal biological functions.

Carbon monoxide consists of one carbon atom and one oxygen atom, connected by a triple bond which consists of two covalent bonds as well as one dative covalent bond. It is the simplest oxocarbon. In coordination complexes the carbon monoxide ligand is called carbonyl.

Carbon monoxide is produced from the partial oxidation of carbon-containing compounds; it forms when there is not enough oxygen to produce carbon dioxide (CO2), such as when operating a stove or an internal combustion engine in an enclosed space. In the presence of oxygen, carbon monoxide burns with a blue flame, producing carbon dioxide. Coal gas, which was widely used before the 1960s for domestic lighting, cooking and heating, had carbon monoxide as a significant constituent. Some processes in modern technology, such as iron smelting, still produce carbon monoxide as a byproduct.

Worldwide, the largest source of carbon monoxide is natural in origin, due to photochemical reactions in the troposphere which generate about 5 x 1012 kilograms per year. Other natural sources of CO include volcanoes, forest fires, and other forms of combustion.

In biology, carbon monoxide is naturally produced by the action of heme oxygenase 1 and 2 on the heme from hemoglobin breakdown. This process produces a certain amount of carboxyhemoglobin in normal persons, even if they do not breathe any carbon monoxide. Following the first report that carbon monoxide is a normal neurotransmitter in 1993, as well as one of three gases that naturally modulate inflammatory responses in the body (the other two being nitric oxide and hydrogen sulfide, carbon monoxide has received a great deal of clinical attention as a biological regulator. In many tissues, all three gases are known to act as anti-inflammatories,  vasodilators, and promoters of neovascular growth. Clinical trials of small amounts of carbon monoxide as a drug are ongoing.

Sources Of Emission
The sources of emission consist of the following listed below:

1. Industrial plant exhaust to air
2. Volcanoes
3. Marsh gases
4. Natural gases in coal mines
5. Forest fires
6. Lightning
7. Vehicle exhaust
8. Tobacco (smoke)
9. Internal combustion engines
10. Heaters (non-electric)
11. Charcoal grills
12. Woodstoves, etc.

Carbon Monoxide Exposure
Most exposure is in the home, by smoking, using unflued gas heaters, malfunctioning equipment (gas water heaters, fuel fired heaters, fireplaces and wood stoves, gas stoves, gas dryers) and using charcoal grills. Exposure may also occur in poorly vented automobiles with defective exhaust systems. Workers in industries that use or produce carbon monoxide are also at risk of exposure.

Carbon monoxide will enter the body if we breathe in contaminated air. Caron monoxide is quickly absorbed into the bloodstream from the lungs.

Carbon Monoxide Environmental Effects
Carbon monoxide increases the amount of other greenhouse gases (methane), and eventually oxidizes into carbon dioxide. Greenhouse gases are linked to global warming. Very high levels of carbon monoxide will cause the same problems to birds and animals that are experienced by people, although these levels are very unlikely to be encountered in the environment except during extreme events like bush fires. At high levels, carbon monoxide will cause illness (fatigue, gastric upset). At very high levels, carbon monoxide will be life-threatening. Long-term (chronic) exposure to low levels of carbon monoxide may produce heart disease and damage to the nervous system. Exposure of pregnant animals to carbon monoxide may cause low birth weight, increased fetal mortality and nervous system damage to the offspring.

Carbon Monoxide Health Effects
Carbon monoxide quickly enters the blood when inhaled into the lungs. Levels normally present in the atmosphere are unlikely to cause ill effects. Carbon monoxide concentration may reach harmful levels in poorly ventilated rooms during operation of unflued gas heaters or defective non-electric heating appliances, or in the passenger compartment of vehicles with defective exhaust systems. At low levels it may cause poor concentration, memory and vision problems, and loss of muscle coordination. At higher levels (200 ppm for 2–3 hours), it may cause headaches, fatigue and nausea. At very high levels (400 ppm) the symptoms intensify and will be life-threatening after three hours. Exposure to levels of 1200 ppm or greater are immediately dangerous to life. Carbon monoxide combines with haemoglobin to form carboxyhaemoglobin, reducing the oxygen-carrying ability of the blood. Long-term (chronic) exposure to low levels of carbon monoxide may produce heart disease and damage the nervous system. Exposure of pregnant women to carbon monoxide may cause low birth weight, increased fetal mortality and nervous system damage to the offspring. Carbon monoxide is classified by the National Occupational Health And Safety Commission (NOHSC) as a Category 1 reproductive toxicant (substance known to cause developmental toxicity to humans).

In conclusion, to be free from this hazard  produced by carbon monoxide the world needs to look for alternative energy solutions.

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