How Long After Smoking Can Carbon Monoxide be Detected (And Why)?

Exact Answer: 20-25 Minutes

No one is unaware of the harmful effects smoking can have on one’s body. Yet many of the people around the world prefer to have it. No doubt smoking has continued its lineage to be the primary reason for lung cancer around the world.



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Carbon monoxide, one of the major components of smoking, is much harmful than you can imagine. The poisonous gas is known to replace the oxygen level in the red blood cells with itself which in turn leads to severe tissue damage or death.

There are variations where the CO concentration ought to be detected in your body- be it some interview or some court proceedings. It becomes really important to know stuff about it.

How Long After Smoking Can Carbon Monoxide be Detected

How Long After Smoking Can Carbon Monoxide be Detected?

Carbon monoxide can be detected in the body, 20 minutes after you have smoked. After 20-25 minutes of smoking, the carbon monoxide content dissolves in your bloodstream, reducing the overall oxygen content in the blood cells.

Now that the time of detection of carbon monoxide is known, you should also be aware of the other stuff related to it. Many people don’t realize how fatal carbon monoxide can be, to the human body.

This gas replaces the oxygen content of the RBCs. The red blood cells consisting of carbon monoxide are much sticky. Due to this, the arteries carrying blood develop a layer of fatty acid around its walls. It causes blockage of the arteries and there is not enough supply to the heart.

The above-mentioned information is to make you aware that, those smoking are at a greater risk of stroke and cardiac arrest. Well if you are thinking about what to do, it’s simple. Quit smoking. All the smokers out there will feel overwhelmed after hearing this. But it’s true, the moment you quit, your body begins to heal in its own way.

The carbon monoxide gas is detectable after 20 minutes because it takes that much time to dissolve in the bloodstream. The gas slowly reaches to normal level after 8-24 hours of smoking.

Carbon Monoxide detectionTime
Presence in the body20 minutes after smoking
Undetectable8-24 hours of smoking

Why Does It Take So Long to Detect Carbon Monoxide After Smoking?

Well, carbon monoxide can be detected in the body after 20 minutes of smoking. It takes this long because of the various changes taking place in the body. Soon after you smoke, the nose linings and esophagus becomes red because of the chemicals and smoke.

After the process, nicotine and carbon monoxide (CO) enters the bloodstream, replacing the oxygen content of the red blood cells. Due to the stimulants present, your brain release (feelgood)chemicals. This is why it takes so long for carbon monoxide to be detected after smoking.

Now there are further changes taking place in the body, once the feel-good chemicals are released by the brain. The chemicals make you want more and more to smoke and as a result, you will end up feeling irritated and anxious.

And now that you know about the detection of carbon monoxide, you should be aware as to when it becomes undetectable. Carbon monoxide starts to leave the system within 10-48 hours of smoking (given, you haven’t tried a single puff during that period).

Smoking not only releases thousands of unwanted chemicals in your system but also reduces your life span. It affects your lungs, heart, and brain severely.

Firstly, smoking lets into your body, almost 70 cancer-causing consists of substances that make you feel addicted. It may also lead to hearing loss and loss of smell taste. Besides, it will stain your teeth and nails. So overall, the wiser option is to quit smoking.


Carbon monoxide is the major component that goes into your body once you smoke. They not only reduce the oxygen component in blood but also prove to be fatal for the body.

There are various instances when there is a need for detection of CO gas, to know about the smoking status. Be it an interview of some firm or some court proceedings. It is always best to know about the knowledge of the presence of carbon monoxide in the body.

The gas can be detected in the body, 20-25 after smoking. And if you are wondering how long the gas to be undetectable, the safe time is 24-25 hours of smoking. Also, smoking is injurious and does no good to the body. Quit smoking. It’s a wiser option.



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