Carbon monoxide
(CO) is a pretty simple gas, consisting of one carbon and one oxygen atom. It
will eventually mate with a spare oxygen atom and reform into the more natural –
and relatively harmless – carbon dioxide, or CO2. But it remains as
CO more than long enough to cause real harm to us mere mortals! Moreover, carbon
monoxide poisoning can be very difficult to treat.
While carbon dioxide (CO2) is not poisonous
as such (in fact the air we breathe naturally contains around 0.03% carbon
dioxide), in sufficient quantity it can displace oxygen in the air and therefore
cause suffocation.
However, carbon monoxide (CO) in any significant
quantity is poisonous because it affects the carrying of oxygen in
our blood. One of the main problems is that CO has 200 times greater affinity
with the haemoglobin in your blood than does oxygen. It literally stops the
blood supply from carrying oxygen around the body and, most importantly, to the
brain. When the brain suffers from oxygen starvation, permanent damage and even
death can result in an amazingly short time – just a few minutes.
Therefore, even if there is a relatively good supply of fresh
air, a relatively small concentration of CO in that air places you in
significant danger.
Where vehicles are concerned, CO is almost always accompanied
by exhaust fumes which do have an odour, so preventative/remedial action can
hopefully be taken. But if you’re a smoker (with already elevated CO levels in
your blood) or suffering from an allergy such as hay fever, there is a real
chance that your sense of smell might be compromised enough not to notice.
So you really need to avoid breathing in CO. The effects also
tend to be cumulative – the body can get rid of it over time but prolonged
exposure can be deadly – literally.
You may have seen those signs in tunnels and deep, long
cuttings asking you to turn off your car engine during delays. There’s a good
reason for that – unfortunately, the signs are ignored by many.
