The New Straits Times, October 17, 1997
Q: According to the API reading of Oct 5, carbon monoxide was the 'dominant pollutant' for Seberang Perai. I also noticed that this was the only place that registered carbon monoxide as the dominant pollutant then. I find this rather strange because the API is rather low Could you please elaborate on this substance?
A: Indeed, carbon monoxide or CO is a common air pollutant, source states that CO accounts for 52 per cent of the pollution caused 98 per cent of total pollution.
In comparison, sulphur oxides account for 18 per cent; hydrocarbon, 12 per cent; particulate matter, 10 per cent, and nitrogen oxides, six per cent. Therefore, it is important to know more about the amount of CO in our air and in our bodies.
Nevertheless, Seberang Perai seems to fit the above typical pattern at the given time. During massive traffic jams, especially, the level of CO can be dangerously high. Whether the description 'dominant pollutant' actually meets the criteria as being hazardous is not clear by just looking at the API.
Although the gas is normally a by-product of a fuel-burning process especially when there is an incomplete combustion of any carbon-containing material, how much of the CO detected in this case is due to the current forest fires in difficult to tell.
More likely, however, this is due to other localised sources like automobile exhaust fumes. Under normal circumstances, carbon dioxide gas is formed.
CO has been described as a 'silent killer ' as it is an odourless, colourless and tasteless gas. It is also non-irritating (unlike sulphur dioxide, nitrogen dioxide and ozone).
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As such it can be completely insidious, and cause death if one is exposed over a long period of time.
In view of this, one needs to be quite careful in interpreting what 'dominant pollutant' means.
In all probability, it is better to avoid any exposure to such a gas. Exposure to high ambient concentrations can result in sufficient haemoglobin saturation to produce unconciousness within minutes, with few if any, premonitory signs.
The initial adverse symptoms of CO can be likened to that of the flu. It causes headaches, nausea, fatigue, dizzy spells as well as irregular breathing. However, unlike the flu, there is no fever.
Fortunately, CO is not a cumulative poison in the usual sense, that is, its effects will generally subside or disappear if one movers away from the area polluted by the gas. On the hand, if the area is revisited, the symptoms will return or recur.
Exposure to low concentration over several hours can be as dangerous as exposure to high levels for a few minutes. Thus, it is important tat we are aware of the symptoms we are experiencing if CO gas is suspected.
If any of these symptoms are present, emergency response is normally indicated.
The US Environmental Protection Agency has established that residential levels are not to exceed nine parts per million (ppm) over an eight-hour average. This is far lower that the US Occupational Safety and Health Administration minimum safety working of 35 ppm for CO over an eight-hour period.
Normally its presence in the body is almost negligible, if any, especially in non-smokers. Because CO is also produced during smoking, the levels in smokers are considerably higher.
The overall concern to our health is the fact that CO can bind thousands of times more readily than oxygen to special cell pigments called haemoglobin (forming carboxyhaemoglobin) in the blood. This will cause the blood cells to carry and deliver a reduced amount of oxygen in the body. By substituting oxygen with CO in our blood, our bodies are poisoned since the needed oxygen is cut off from the organs causing variable damages.
Thus, CO can disrupt many other cellular activities, contributing to the impairment of the function of organs that use large amounts of oxygen, especially the brain and the heart. The elderly, children and unborn children are at greater risk when exposed to the gas in view of the vulnerability of such organ system.
