Carbon Monoxide- the Silent Killer

Carbon Monoxide- the Silent Killer

What is carbon monoxide, and how does it affect humans?

Carbon monoxide is a gas found in air. It is a colourless, tasteless and odourless compound produced by incomplete combustion of carbon-containing materials. High levels of carbon monoxide are poisonous to humans and, unfortunately, it cannot be detected by humans as it has no taste or smell and cannot be seen. It is also difficult to treat once the damage is done, carbon monoxide is known as the silent killer.

Carbon monoxide affects healthy and unhealthy people. Increased levels of carbon monoxide reduce the amount of oxygen carried by haemoglobin around the body in red blood cells. The result is that vital organs, such as the brain, nervous tissues and the heart, do not receive enough oxygen to work properly.

For healthy people, the most likely impact of a small increase in the level of carbon monoxide is that they will have trouble concentrating. Some people might become a bit clumsy as their coordination is affected, and they could get tired more easily.

People with heart problems are likely to suffer from more frequent and longer angina attacks, and they would be at greater risk of heart attack. Children and unborn babies are particularly at risk because they are smaller and their bodies are still growing and developing.

How does carbon monoxide detectors work?

Carbon monoxide detectors sound an alarm when they sense a certain amount of carbon monoxide in the air over time. Different types of alarms are triggered by different types of sensors.

  • Biomimetic sensor: A gel changes colour when it absorbs carbon monoxide, and this colour change triggers the alarm.
  • Metal oxide semiconductor: When the silica chip’s circuitry detects carbon monoxide, it lowers the electrical resistance, and this change triggers the alarm.
  • Electrochemical sensor: Electrodes immersed in a chemical solution sense changes in electrical currents when they come into contact with carbon dioxide, and this change triggers the alarm.

Once the alarm sounds, the carbon monoxide detector must be in a carbon monoxide-free environment to reset itself.

Carbon Monoxide is released as a by-product of a combustion (burning) process. Any household appliance that burns natural gas, coal, oil, bottled gas, paraffin, wood, petrol, diesel or charcoal will produce some levels of CO. The level produced will vary depending on the type of fuel being burnt and the quality of the service and maintenance of the appliances.

  • Always fit a CO alarm in rooms with fuel burning appliances
  • Fitting at least 2 interconnected alarms will:
    • Enhance early detection of CO
    • Raise the alarm sound levels throughout the house
  • If there is only one appliance in the house, consider fitting an additional alarm in the bedroom area.
  • CO alarms must always be fitted in conjunction with a standard smoke alarm they are not intended to be used as the sole detection device.

Where should you place carbon monoxide detectors?

  • Living rooms with high occupancy
  • Bedrooms above or adjacent to room with appliance
  • Rooms with chimney breasts passing through them, e.g. upstairs bedroom
  • Rooms with portable gas / oil heaters
  • Parking garages

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