Carbon Monoxide— an introduction
Shivi Jain
When you generally combust a carbon fuel, the phenomenon that takes place is complete combustion. It happens in the presence of sufficient oxygen, and the products formed are always Carbon dioxide + water vapor.
The general equation then would be given by– Fuel+ O2 → CO2+H2O
But what happens when oxygen isn’t sufficient?
What happens is incomplete combustion, And as in so many other cases where lack of oxygen is always harmful, so is the case here again. Because in incomplete combustion, the carbon monoxide gas is formed alongside H2O. and CO is much more hazardous than CO2. Now in an atmosphere with abundant oxygen, how does incomplete combustion even happen?
There are many reasons for this. For example, malfunctioning ventilation in fuel burning appliances- such as, furnaces, stoves, water heaters, and even our cars in garages.
| Composition and presence in the air
A single molecule of Carbon Monoxide is formed when one oxygen atom and one carbon atom form a coordinate covalent triple bond. This also makes it an unsaturated compound, seeing as it is triple bonded.
The presence of this gas in the air is so less in amount, and so widespread around the atmosphere, that it’s quite literally negligible. Take it this way- in every billion parts of air, only around a hundred parts of those are typically CO in the troposphere outdoors.
The normal background level of CO indoors, may depend upon factors such as cigarette smoke, and the types of heating and cooking fuels used.
The World Health Organization (WHO) estimates that indoors the concentration of CO should be no more than 9 ppm for any eight-hour period, and 25 ppm for one hour period, and no more than 90-100 ppm for fifteen minutes.
| Why is it harmful?
As in regular respiration, when you accidentally (or purposefully- don’t do that!) inhale CO, it diffuses into your bloodstream.
The pigment hemoglobin present in blood, has an affinity for oxygen. Molecules of Oxygen bind to the pigment and that is what helps transport Oxygen all through the body. But Carbon Monoxide binds to hemoglobin much more strongly than Oxygen does. And when this happens, the CO starts displacing the Oxygen molecules.
The CO binding with hemoglobin largely reduces its ability to carry oxygen, and hence there is a scarcity of Oxygen (hypoxia) in the blood cells. This further leads to tissue hypoxia.
When the tissues in our body don’t get enough oxygen, cells are unable to function properly. Energy generation also gradually declines when respiration becomes anaerobic. When you first inhale the gas, you’ll initially feel dizzy, and may get a headache. These short-term symptoms also include feeling weakness, nauseous or even confusion. Long term symptoms are much more harmful.
CO poisoning is a pretty serious case. In many cases, the person may lose consciousness, even get a seizure, go into a coma, or eventually die.
| Sensors
Now, how do you avoid a gas you can’t even see?
To tackle this problem we have gas sensors, and there are also ones specifically for the gas. Installing these in homes is certainly one way we can avoid CO poisoning.
Industrial carbon monoxide (CO) sensors are used to detect dangerous levels of CO in industrial facilities, such as warehouses, breweries, and parking garages. A standard CO sensor can measure up to 1,000 or 1,500 ppm, which might not be enough for all industries and applications. For example, the Carbon Monoxide high range sensor is commonly used in the steel industry and mine rescue applications.
Other than the big and expensive industrial use sensors there are also gas detectors you can install at homes. A CO alarm is a time-weighted alarm. It works by calculating the accumulation of Carbon Monoxide in a house. To get CO poisoning, you need to be uncovered to 50 ppm for eight hours. The response of the CO alarm depends on the amount of CO in the air. The alarm will make noise after half an hour of continuous exposure at a level of 50 ppm.
| It’s not all bad
Though it is a lethal and deadly gas– CO is actually also a vital component in the industry.
• For example, when compressed under great pressure it turns to liquid. CO in liquid form is used in industrial processes as a fuel. And other than in industries it is also used in homes as a cooking fuel, in heaters and in motor vehicles.
• Carbon Monoxide is also useful in metallurgy. It is passed through hot iron oxides, which reduce to metallic iron, while carbon monoxide is oxidized to carbon dioxide.
• CO reacts with Cobalt, Iron and Nickel to form compounds called Carbonyls. Carbonyls have abnormal chemical and physical properties that are used in the industry for loading and unloading of cargos.
• Now CO sure is a deadly gas, but despite that it can act as a neurotransmitter created in small amounts by enzymatic and non-enzymatic processes and is used as a medicinal agent.
| How we can prevent CO poisoning
• Care should be taken while installing appliances as per the instructions of manufacturer and professionals.
• Chimneys should be checked for any defaults in the metal or imperfect connections. Further, your heating systems should be serviced at least once a year.
• In a bedroom, fuel using appliances should not be used, and never use a kitchen range to heat the house. In garages, even if the door is open, it is not advisable to leave a car running.
• CO detectors should of course be placed. Make sure the alarm sound is working, and the batteries should be tested and replaced at least twice a year.
• Open the windows at least once a day- preferably in the mornings to let fresh air circulate through the house.
