Emphasis on "just". Yes, obviously getting fresh air is an important step when you suffer from CO poisoning but it's not sufficient. Even the site you linked to mentions you should get additional treatment.
Intuitively most people would think that just stopping to breathe CO is sufficient and breathing fresh air would displace it as quickly as with other common gasses (i.e. you may cough for a bit but recover in minutes) but the point is that CO is clingy.
EDIT: Elsewhere you agree with the assessment that the half-life under "fresh air" is somewhere around 4 hours, so I think you would agree that "just breathe fresh air for a bit" (implying minutes, maybe an hour) isn't a satisfactory treatment in serious cases.
3-4 hours is "a bit" when compared to the multiple weeks the GP suggested...
You should absolutely seek medical treatment if you suspect you have been exposed to CO. I'm not trying to make light of that. My point is simply that CO is not actually as "clingy" as some in this thread are making it out to be.
I am a paramedic. We carry a portable CO meter on our "BLS bag" (the bag that gets brought in on the vast majority of calls), because more than once a "general illness" call has turned out to be CO poisoning.
"Standard" PPE (personal protective equipment) is basically our standard uniform[1], plus nitrile gloves and a radio. Additional levels of PPE include safety glasses, gowns[2], and full face shields. We also carry ballistic vests in the event a potentially violent scene.
We are a combination fire/EMS agency, so I am also a firefighter, with all the gear that goes along with that.
As far as the bags go, we have three main bags:
-The "BLS" or "Airway" bag, which contains a lot of "basic" equipment (bandages, oxygen, some common meds, etc), as well as more advanced airway management equipment (laryngoscopes and endotracheal intubation tubes, etc).
-The "ALS" or "Med" bag, which contains all ~30 medications we carry, as well as IV fluids and all the necessary pointy things to get medications into people.
-The "Pediatric" or "Peds" bag, which contains most of the same stuff as the other two bags, just in smaller quantities, and sized for kids.
There are also a few other more specialized bags (the burn bag, the trauma bag, etc), and portable equipment (portable heart monitor[3], suction[4], etc)
"After the patient has been removed to a safe area, it is important to immediately begin administration of high concentration oxygen to maximize hemoglobin oxygen saturation. Treatment and monitoring of the patient with CO exposure should continue on scene and en route to the hospital. Continuously monitor SpO2 and SpCO levels, obtain a 12-lead EKG and monitor the ECG en route. Remember that SpO2 monitoring alone is unreliable as you may get a falsely normal reading in the presence of carbon monoxide poisoning."
As with all poisons, that depends on the dose... For a low level exposure, fresh air is truly all that's needed.
I'm not trying to suggest that more advanced treatment is never necessary (I am the person who provides that treatment...), my point is simply that there are _many_ people who experience low level, chronic exposures to carbon monoxide that require no further treatment than leaving the environment.
Yes you can...
http://www.remsaeducation.com/news/carbon-monoxide-poisoning...