Carbon Monoxide (CO)
Can be measured with:
✓ measurable with air‑Q basic and air‑Q pro as well as air‑Q science
air-Qs with a sensor for Carbon Monoxide
Description:
Carbon monoxide (CO) refers to a simple inorganic compound of carbon and oxygen. It is a colorless, odorless and tasteless gas. With oxygen it burns with a blue, transparent flame to form carbon dioxide. The gas is a dangerous respiratory poison. If it enters the bloodstream, for example through smoking tobacco, carbon monoxide binds to the hemoglobin in the blood approximately 210 times more strongly than oxygen. This can permanently impair oxygen transport and cause fatal carbon monoxide poisoning. Even a saturation of 1.28% carbon monoxide in indoor air leads to death within one to two minutes. Carbon monoxide is somewhat lighter than air and tends to rise, but due to air turbulence it can be found anywhere in a room.
In industry, pure carbon monoxide is used to produce formic acid and sodium formate. It is also used to convert chlorine into phosgene and methanol into acetic acid. In addition, it serves as a reducing agent for iron ore.
Limit values for carbon monoxide:
The normal concentration of CO in the air is approximately 0.6 to 6 mg/m³. In unventilated rooms with gas burners, fireplaces or from cigarette smoke, 30 mg/m³ can easily be reached.
According to the German Federal Environment Agency, the highest 8-hour average value must not exceed approximately 10 mg/m³. The maximum workplace concentration (MAK value) for carbon monoxide is given as 35 mg/m³. The WHO recommends values above 25 mg/m³ for a maximum of one hour, and values up to 85 mg/m³ for a maximum of 15 minutes. These values do not apply to pregnant women or people with pre-existing conditions.
| Designation | Carbon monoxide limit values |
| UBA 24h guideline value | 4 mg/m³ (3.2 ppm) |
| UBA 8h guideline value | 10 mg/m³ (8 ppm) |
| WHO recommendation 1h value | 25 mg/m³ (20 ppm) |
| MAK value | 35 mg/m³ (28 ppm) |
| UBA guideline value 15 min | 100 mg/m³ (80 ppm) |
| WHO recommendation 15 min value | 85 mg/m³ (68 ppm) |
Effects of excessive CO concentration:
A continuous eight-hour exposure at a CO concentration below 60 mg/m³ is barely dangerous for healthy adults. However, sick and pre-affected individuals can experience impairments even at low values. For example, hearing loss can be worsened by up to 50% by carbon monoxide.
Even at a relatively low exposure to carbon monoxide of between 80 and 120 mg/m³ over several hours, initial physical impairments can be observed. These mainly include cold-like symptoms, such as a runny nose, headaches, shortness of breath and sore eyes.
If the CO concentration rises to values between 170 and 350 mg/m³, fatigue, dizziness and nausea occur after two to three hours. From a value of 460 mg/m³, exposure is considered extreme and immediately life-threatening. Unconsciousness and permanent brain damage are imminent. After three hours at the latest, such a concentration can lead to death. At even higher values, death occurs even sooner. After carbon monoxide poisoning, it is not enough to simply breathe fresh air to compensate for the oxygen deficiency in the blood. Compensating for the oxygen deficiency in the blood and the body's regeneration can only happen by supplying a disproportionately large amount of oxygen.
Formation of CO:
Indoors, the carbon monoxide content of the air generally enters through ventilation - the main source in residential areas is road traffic. Concentrations of over 5 mg/m³ can prevail, depending on the proximity of the location to traffic. But leaky or malfunctioning fireplaces and stoves, gas stoves and propane-powered heaters also emit CO and increase the concentration. In addition, burning wood, wood pellets or charcoal leads to elevated carbon monoxide levels. If ventilation in the room then does not function correctly, CO poisoning can occur. More on this in the linked blog post.
Sensor used:
Carbon monoxide is measured by means of an electrochemical sensor. CO molecules that "dock" onto the surface of the sensor cause a small current in the sensor. The advantage of our sensor is the individual sensitivity calibration by the manufacturer and its particularly long service life. The disadvantage of electrochemical CO sensors is slight cross-sensitivities.
The sensor we use has a slight cross-sensitivity to hydrogen (H2). It accordingly reacts somewhat to this gas and then shows a reading, even if no CO is present.
Measuring carbon monoxide:
The air-Q air quality measuring device and carbon monoxide detector is a particularly powerful and comprehensive measuring device. Many facts about the technology behind the air-Q can be found here. You can order the air-Q in the online shop.
More measured values / sensors
