How much Carbon Monoxide can harm me?

Even tiny amounts of carbon monoxide can cause harm; and long term exposure to small amounts of CO (assuming they are not fatal) can even cause permanent brain damage.

The presence of Carbon Monoxide is measured in parts per million.  The following table gives an indication of the harm different amounts of the gas can cause:

A Carbon Monoxide Alarm should give a shrill alarm within the following timetables (according to European Standard EN50291:2001), so protecting you from illness or death, even if you are asleep:

Carbon Monoxide harms by entering the lungs as you breathe normally and displacing oxygen from the bloodstream.  This interrupts the normal supply of oxygen to the vital organs and puts your life at risk.