Carbon monoxide can cause harmful effects by reducing oxygen delivery to the body's organs and tissues. CO replaces oxygen in the bloodstream, eventually causing suffocation. Mild CO poisoning feels like the flu, but more serious poisoning leads to difficulty breathing and even death.
Cardiovascular Effects The health threat from lower levels of CO is most serious for those who suffer from heart disease, like angina, clogged arteries or congestive heart failure. For a person with heart disease, a single exposure to CO at low levels may cause chest pain and reduce that person's ability to exercise; repeated exposures may contribute to other cardiovascular effects.
Central Nervous System Effects Even healthy people can be effected by high levels of CO. People who breathe high levels of CO can develop vision problems, reduced ability to work or learn, reduced manual dexterity and difficulty performing complex tasks. At extremely high levels, CO is poisonous and can cause death.
Just how sick people get from CO exposure varies greatly from person to person, depending on age, overall health, the concentration of the exposure (measured in parts per million) and the length of the exposure.
|
Concentration (parts per million)
|
Symptoms
|
|
35 |
No adverse effects within 8 hours. |
|
200 |
Mild headache after 2-3 hours of exposure. |
|
400 |
Headache and nausea after 1-2 hours of exposure. |
|
800 |
Headache, nausea and dizziness after 45 minutes; collapse after 2 hours. |
|
1,000 |
Loss of consciousness after 1 hour. |
|
1,600 |
Headache, nausea and dizziness after 20 minutes; unconsciousness after 30 minutes. |
|
3,200 |
Headache, nausea and dizziness after 5-10 minutes; unconsciousness after 30 minutes. |
|
12,800 |
Immediate physiological effects; unconsciousness and danger of death 1-3 minutes |
Effects of Carboxyhemoglobin (COHb) Saturation
When carbon monoxide replaces oxygen in the blood, a condition known as carboxyhemoglobin (COHb) saturation results. COHb levels do not consider the length of exposure. As more and more CO accumulates in the blood, the percentage of COHb gets higher and higher and people get sicker and sicker.
|
COHb Saturation (%)
|
Symptoms |
|
0-10 |
None |
|
10-20 |
Tension in forehead, dilation of skin vessels. |
|
20-30 |
Headache and pulsating temples. |
|
30-40 |
Severe headache, weariness, dizziness, weakened sight, nausea, vomiting, prostration. |
|
40-50 |
Same as above plus increased breathing and pulse rates, asphyxiation. |
|
50-60 |
Same as above plus coma, convulsions |
|
60-70 |
Coma, convulsions, weak respiration and pulse. Death is possible. |
|
70-80 |
Slowing and stopping of breathing, death within hours. |
|
80-90 |
Death in less than 1 hour. |
|
90-100 |
Death within a few minutes. |
