Carbon Monoxide - What is Carbon Monoxide (CO)?
Carbon Monoxide is the leading cause of accidental poisoning deaths in America, according to the Journal of the American Medical Association (JAMA). 1,500 people die annually due to accidental carbon monoxide poisoning, and additional 10,000 seek medical attention. (Medical experts agree that it's difficult to estimate the total number of carbon monoxide poisoning incidents because the symptoms of carbon monoxide poisoning resemble so many other common ailments.)
Common sources that may lead to carbon monoxide poisoning include house fires, furnaces or heaters, wood-burning stoves, motor vehicle exhaust, propane-fueled equipment such as portable camping stoves, ice resurfacers, forklifts, and gasoline-powered tools such as high-pressure washers, concrete cutting saws, power trowels, floor buffers, and welders used in buildings or semi-enclosed spaces carbon monoxide poisoning can also occur in scuba diving due to faulty or badly sited diving air compressors. Generators and propulsion engines on boats, especially houseboats, have resulted in fatal carbon monoxide exposures. Another source is exposure to the organic solvent methylene chloride, which is metabolized to CO by the body.
Carbon monoxide is a flammable, colorless, odorless, tasteless toxic gas produced during incomplete combustion of fuel - Natural Gas, Oil, Coal, Wood, Kerosene, etc. and can not be detected without the use of a carbon monoxide detector.
During normal combustion, each atom of carbon in the burning fuel joins with two atoms of oxygen - forming a harmless gas called carbon dioxide. When there is a lack of oxygen to ensure complete combustion of the fuel, each atom of carbon links up with only one atom of oxygen - forming carbon monoxide gas.
Carbon monoxide is a significantly toxic gas and has no odor or color. It is the most common type of fatal poisoning in many countries. Exposures can lead to significant toxicity of the central nervous system and heart. Following carbon monoxide poisoning, long-term sequelae often occurs. Carbon monoxide can also have severe effects on the foetus of a pregnant woman.
Carbon Monoxide In The Air
Carbon monoxide is a significantly toxic gas, although patients with carbon monoxide poisoning may demonstrate varied clinical manifestations with different outcomes, even under similar exposure conditions. Toxicity is also increased by several factors, including: increased activity and rate of ventilation, pre-existing cerebral or cardiovascular disease, reduced cardiac output, anemia or other hematological disorders, decreased barometric pressure, and high metabolic rate.
Carbon monoxide poisoning is life-threatening to humans and other aerobic forms of life, as inhaling even relatively small amounts of it can lead to hypoxic injury, neurological damage, and possibly death. A concentration of as little as 0.04% (400 parts per million) carbon monoxide in the air can be fatal. The gas is especially dangerous because it is not easily detected by human senses. One report concluded that carbon monoxide exposure can lead to significant loss of lifespan after exposure due to damage to the heart muscle.
Symptoms of mild carbon monoxide poisoning include headaches and dizziness at concentrations less than 100 ppm. Concentrations as low as 667 ppm can cause up to 50% of the body's haemoglobin to be converted to carboxy-haemoglobin (HbCO). Carboxy-haemoglobin is quite stable but this change is reversible. Carboxy-haemoglobin is ineffective for delivering oxygen, resulting in some body parts not receiving oxygen needed. As a result, exposures of this level can be life-threatening. In the United States, OSHA limits long-term workplace exposure levels to 50 ppm.
The poisoning effects produced by carbon monoxide in relation to ambient concentration in parts per million are listed below:
What is the Danger to Me?
Carbon monoxide inhibits the blood's capacity to carry oxygen. In out lungs, CO quickly passes into our bloodstream and attaches itself to hemoglobin (oxygen carrying pigment in red blood cells). Hemoglobin readily accepts carbon monoxide - even over the life giving oxygen atoms (as much as 200 times as readily as oxygen) forming a toxic compound known as carboxyhemoglobin (COHb).
By replacing oxygen with carbon monoxide in our blood, our bodies poison themselves by cutting off the needed oxygen to our organs and cells, causing various amounts of damage - depending on exposure.
Chart describing symptoms of CO Poisoning from CO SUPPORT study.
Low levels of carbon monoxide poisoning (with COHb levels of 10%) result in symptoms commonly mistaken for common flu and cold symptoms - shortness of breath on mild exertion, mild headaches, nausea.
With higher levels of carbon monoxide poisoning (COHb levels of 30%) the symptoms become more severe - dizziness, mental confusion, severe headaches, nausea, fainting on mild exertion.
At high levels (CHOb of 50% or more) there may be unconsciousness and death.
The mechanisms by which carbon monoxide produces toxic effects are not yet fully understood, but haemoglobin, myoglobin, and mitochondrial cytochrome oxidase are thought to be compromised. Treatment largely consists of administering 100% oxygen or hyperbaric oxygen therapy, although the optimum treatment remains controversial. Domestic carbon monoxide poisoning can be prevented by the use of household carbon monoxide detectors.
HOW DOES CO ENTER THE HOME?
Carbon monoxide can escape from any fuel-burning appliance, furnace, water heater, fireplace, woodstove, or space heater.
Most newer homes are built very air-tight, thus cutting down on the supply of fresh air to your furnace - and creating an oxygen starved flame. Tight closing replacement windows and doors, as well as additional insulation can cause similar problems in older homes.
Carbon monoxide can spill from vent connections in poorly maintained or blocked chimneys. If the flue liner is cracked or deteriorated, CO can seep through the liner and into the house - slowly creeping up to dangerous levels. If a nest or other materials restrict or block the flue, CO will mostly spill back into the house.
Improperly sized flues connected to new high-efficiency furnaces and water heaters can also contribute to CO spillage. (Many new furnaces and water heaters are installed using the existing chimneys which may be the wrong size to allow the furnace to vent properly.)
Warming up vehicles in an attached garage, even with the garage door opened, can allow concentrated amounts of CO to enter your home through the car port door or near-by windows.
WHAT TO DO IN A CO EMERGENCY.
If you are suffering from chronic flu-like symptoms, see your doctor and ask him if it could be a low-level CO poisoning.
If you have a CO detector, and it alarms, open windows and ventilate your home w/ fresh air, have your heating system checked by a professional.
If your alarm sounds and you are feeling drowsy or dizzy, leave the house and call 911 from your neighbors home. You may need medical attention for CO poisoning.
Carbon Monoxide Detectors w/ PPM Displays and Battery Backup
Although all home carbon monoxide detectors use an audible alarm signal as the primary indicator, some versions also offer a digital readout of the CO concentration, in parts per million.
Typically, they can display both the current reading and a peak reading from memory of the highest level measured over a period of time.
The digital models offer the advantage of being able to observe levels that are below the alarm threshold, learn about levels that may have occurred during an absence, and assess the degree of hazard if the alarm sounds.
They may also aid emergency responders in evaluating the level of past or ongoing exposure or danger.