BBC: Carbon monoxide's damaging role in heart rhythm found
The BBC reports on a study showing that low levels of carbon monoxide, in the range encountered from vehicle traffic, can cause cardiac arrhythmia:
Carbon monoxide is produced by faulty boilers, cigarettes and car exhausts.
It is deadly at high levels as it "shoulder-barges" oxygen out of the blood, meaning less is transported around the body. Carbon monoxide poisoning kills more than 50 people in the UK each year and many more around the world.