It’s in the Air – Carbon Monoxide

Colourless, odourless and imperceptible to the senses, if there ever was a literary description for a perfect assassin, then the adjectives listed above must have been used to describe one. However, a gas that is lethal at as little as 0.5% volume per one’s body weight and since the mid-2000s has become increasingly ubiquitous poses undeniable danger and a cause for concern.

CO1-WarningCarbon monoxide is formed when carbon combines with a limited supply of oxygen. By far the most common source of carbon monoxide is from vehicular traffic and research has shown that the engines of larger vehicles like trucks especially produce significantly higher levels of carbon monoxide than smaller vehicles. In addition to the difference in the sizes and age of engines/vehicles, the types of fuels being used by the engines also plays a significant role as diesel engines have been shown to produce more carbon monoxide than petrol engines and this applies not just to vehicles but electricity generators as well. Carbon monoxide is also formed naturally during volcanic activity as well as in the upper atmosphere when ozone is broken down and forced to react with atmospheric carbon dioxide. In the UK, heaters and cookers/ovens were usually powered by coke gas: a combination of CO and hydrogen gas, although it has been banned due to the deleterious health effects from accidents involving this gas and in some cases people used it as a means to commit suicide.

In blood, haemoglobin (Hb) is the compound that is responsible for the exchange of oxygen and carbon dioxide between the cells and in the lungs. Haemoglobin however, has an uncanny characteristic of having higher affinity for carbon monoxide than it has for either carbon dioxide or oxygen. When carbon monoxide combines with haemoglobin, it forms an unyielding new compound (carboxyhaemoglobin – COHb) that rids blood off its ability to act as a medium of exchange for respiratory gases. The end result here is something called asphyxiation, the equivalent of which is a fish drowning in water.


Lagos is a special case due not only to the traffic volume especially in areas like Apapa and the Mile 2 – Festac environs where there are significant levels of HGV traffic or along the Lagos-Abeokuta Expressway that arguably hosts the highest daily traffic volume in West Africa as it carries commuters from Alimosho (Lagos’ most populated LGA) to the Island (Lagos’ Corporate HQ). It is also the reality that Lagos is the single region in Africa having the highest numbers of portable and industrial electricity generators and these work in some cases for 24 hours around commercial and residential buildings.

Research has shown the levels of CO that are produced by different sources that may be encountered in everyday living. They range from burning firewood where levels may be significantly lower than 5ppm; to operating petrol and diesel engine generators; to emissions from vehicles where they may get as high as 500ppm.

sources 2
levels of CO per source (Kayode & Kamson, 2013)

From all considered sources, it becomes imperative that people who spend longer periods in traffic like commercial traffic workers and commuters on their ways to and from places of work are at greater risk of suffering the ill effects of carbon monoxide exposure. Also, people such as truck technicians as well as those who live and work around places where they are constantly operated may be at significant risk.

According to chemistry, as little as 0.5% volume of per body weight of carbon monoxide in a human will result in death and this is something that has been widely reported albeit under the guises of headlines that read “Generator Kills Family of 5” and similar titles. In instances when the carbon monoxide concentration is not high enough to cause death to the people around, it exhibits its effects by inducing cardiac events; it has been known to cause seizures in grown adults; headaches; dizziness; tightness in the chest/shortness of breath; loss of nervous composure; and may induce personality changes that express themselves as shortness of temper, rage and confusion and funny enough these are tell-tale signs that are exhibited by people who have spent some time in Lagos traffic. It is an interesting proposition anyway; could it be possible that the pollutants in the ambient air are responsible for Lagos’ driver unbearable driving behaviours?

carbon-monoxide1Away from traffic, carbon monoxide exerts a strong negative effect in the residential areas through generator fumes. These fumes generally hang around homes as generator fumes and are particularly harmful to the more active little children. Breathing in carbon monoxide over long periods does not only add to instances where children develop respiratory conditions like asthma, it reduces children’s immunity and leaves them more predisposed to other diseases especially malaria. Other long-term effects include stunted growth and reduction in mental acuity that sees the affected child seeming intellectually slow (does bad at school, does not retain information properly and is often lethargic) compared with their peers. Also, due their bodies being considerably smaller, children are at greater risk of death by carbon monoxide poisoning as a lot less of the gas is needed in their system to cause death.

Guidelines regarding exposure limits for humans have been ascertained and given by invested agencies like the US Environmental Protection Agency (US-EPA). Over one hour, if exposure to CO is kept under 9ppm (parts per million of atmospheric air), there would be little or no adverse effects; over 8 hours (long term exposure) if kept CO levels under an average of 24ppm it may be relatively safe; and as a “fun fact”, CO levels reaching 12,800ppm (starting a generator in a poorly ventilated area would make this happen in a few minutes) would kill a full-grown adult in less than 3 minutes. However, research studies conducted around Lagos show that the average CO levels measured hourly around major areas with varying levels of vehicular traffic volumes are as high as almost 80ppm while those from generators (petrol and diesel) produced an average of around 70ppm. Compared against standards protecting human welfare, this is undeniably unhealthy but in open air, the wind acts primarily as a dispersal mechanism and spreads the ambient pollutants over wider regions of lower concentration (but even when this happens and hourly average measurements still look like what is shown below with Isolo which is has the lowest recorded levels from this study being over 3 times the 9ppm limit for hourly exposure, don’t take risks with your health; protect yourself.)

CO Concentrations from cars in different locations (Akinyemi & Usikalu, 2013)

Although the focus has primarily been on carbon monoxide, it is by no means the only dangerous pollutant of concern. Compounds like nitrogen oxides, volatile organic substances, sulphur oxides and even lead have been recorded in significant levels from vehicular traffic. These compounds have been known to exert effects that range from respiratory irritations to cancer and even more recently, being identified as teratogens meaning they are substances that contribute to the manifestation of deformities in unborn children. The EU as at 2015 spent an incredible £1.6tr on cleaning and maintaining the air; an effort that has reflected in the average levels of air quality and corresponding health issues although, the situation in bigger cities like London and Paris still remains a cause for concern. In Africa however where trillions of pounds are not available to be thrown in the air – quite literally, the fact remains that driving through traffic in bigger cities like Lagos, is a health hazard.

However, staying off the road especially during traffic peak periods is a good first step in protecting oneself from CO exposure especially if you have kids. In the events that they have to be dropped off at school, etc. using the vehicle’s air conditioner is a good idea – it protects your health and that of the children on board. Practically, do everything possible – look for alternative routes even if they may be longer – to ensure you spend as little time in congested traffic as possible. Keep away from areas with high truck/trailer traffic or if you reside in places where the infrastructure is available; just take the train or another non-road alternative. In dealing with generators, considering the health effects, it is advisable that one invests in more sustainable source of electricity i.e. solar panels, inverters, etc. and paying regularly paying electricity bills. Reducing the periods generators are run for and keeping them a considerable distance from human habitations is another noble way to go; if your health and that of your kids isn’t your concern then perhaps, other people care about themselves and their kids a lot more than you do and their sacrifice need not be demeaned (this is without event talking about the psychological effects of generator noise). By far however, educating other people about the dangers that this pollutant poses is the most powerful means of bringing it under control. In the time between now and when the authorities can afford to protect the health of citizens by pursuing cleaner air through better monitoring, regulation, traffic control and power supply, doing our best to protect ourselves will not be the worst of ideas.

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