That's why you should install a portable carbon monoxide detector in your motor, not just your home, warns a leading gas safety expert.
"Changes in mood, sudden bursts of anger and loss of concentration could be indicators you are being exposed to CO emissions in your car," warns Ranjen Gohri a carbon monoxide safety expert at 24/7 Home Rescue and Vehicle Service.
While most of us are aware of the risks of carbon monoxide poisoning from a leaky boiler at home, many don't realise their car could be leaking the deadly gas too.
"Being stuck in increasingly heavy traffic could be putting motorists at even greater risk," says Ranjen.
"The threat is real and exposure can have devastating consequences."
The good news, however, is you can take precautions to greatly reduce the risks, and drive your vehicle with peace of mind.
Ranjen says: "There are a number of measures you can take to dramatically reduce your risk of carbon monoxide poisoning in your vehicle.
"These include ensuring your exhaust system is in good working order," he notes.
Ranjen suggests a portable carbon monoxide detector ensures extra safety and points out, "You have them in your home, you should have one in your car too."
Known as the silent killer, carbon monoxide is a colourless, odourless, toxic flammable gas which is formed by the incomplete combustion of carbon.
High levels of exposure can cause death rapidly, while low levels can gradually take their toll without the victim suspecting CO emissions are to blame.
Common signs of lower levels of exposure include headaches, tiredness, dizzy spells, shortness of breath and nausea.
Mental health and behavioural issues may also be signals because lower level poisoning affects white matter and a part of the central brain called the basal ganglia which is associated with a variety of movements, habit learning, cognition and emotions.
Disrupting this part of the brain can induce the unusual behaviour. This can range from random out of character acts to different emotional waves.
"Carbon monoxide poisoning could cause a person to behave in a way they don't usually behave," says Ranjen.
"Long-term exposure to low levels means temperament can get worse so if you're getting a daily dose of carbon monoxide in your car, it could potentially affect your driving and behaviour behind the wheel."
Ranjen's concerns are backed up by brain injury charity Headway who say low-level CO poisoning may not be recognised:
"The symptoms include milder versions of those seen in acute CO poisoning, with headache, nausea, dizziness, light-headedness, fatigue and sleepiness, difficulty concentrating and memory problems, as well as changes in mood.
"People may be aware that something is wrong, but be unable to identify exactly what is the matter, or may attribute the problems to overwork, stress or depression. If symptoms disappear while away at work, reappearing on returning home, or if other people in the same premises develop similar symptoms, it may become more obvious that there is an environmental cause."
Around 50 Brits die from carbon monoxide poisoning each year. A further 4,000 make medical visits, according to the Department of Health.
Here are Ranjen's safety tips to ensure your car is CO free:
The exhaust system is crucial and must be checked regularly, he stresses.
"You should inspect and get it repaired frequently. Leaks can mean carbon monoxide enters your vehicle.
"It's especially dangerous if the exhaust system is leaking between the engine and catalytic converter," says Ranjen.
Make sure you engine is tuned up and your emissions system is regularly checked.
"Usually the concentration of carbon monoxide in the exhaust of newer cars is low," notes Ranjen.
"But levels can go through the roof if the engine is out of tune or the emissions system is faulty."
Never have your engine running if your motor is partially covered in snow.
Ranjen explains: "If the tailpipe is partially blocked with snow exhaust fumes may be redirected under the car and enter the passage compartment."
Avoid driving a car with holes in the floor or in the trunk, or with the trunk open.
"If there are holes in the bottom of the car it may mean exhaust fumes are entering your vehicle.
"This is especially dangerous if you sit in traffic a lot or if your exhaust system has leaked," Ranjen explains.
If you drive a pick-up truck you should never let anyone ride in the back with the canopy over the top.
"They aren't sealed like a passenger compartment, so this means carbon monoxide levels can quickly rise with the driver completely unaware."
Always avoid running your car inside a garage or any closed space.
"Even if your windows are rolled up or the garage door is wide open you are still at great risk of carbon monoxide levels spiking to dangerous levels."
Stoping and starting your engine in a bid to keep your car warm can also generate more carbon monoxide fumes.
'It can generate more carbon monoxide than if you just run it continuously," warns Ranjen.
Lastly and most importantly install a battery powered carbon monoxide detector.
"Carbon monoxide is odourless and colourless, you can't see it or smell it. So get a detector for your car, its the only way to know your safe," Ranjen urges.
https://www.247homerescue.co.uk