IT is common to see people sleeping in their vehicles. This issue is related to the case of a woman found dead in her car at Ipoh's Raja Permaisuri Bainun Hospital parking lot on Tuesday.
I see this among stall owners in wet markets. They arrive in the early hours of the morning to arrange their goods.
The managing of the stalls will then be handed to their assistants and the owners will sleep in their cars. Some sleep with the engine running and some sleep with the engine switched off. In most cases, the windows are closed.
In the Ipoh case, the victim succumbed to asphyxiation. Death due to sleeping in cars is most often the result of asphyxiation. Atmospheric air contains 21 per cent oxygen.
When we breathe, our body uses up about five per cent of the oxygen. The air we exhale contains about 16 per cent oxygen.
When a car is moving, the oxygen content in the car is replenished with external air forced into the car.
For a stationary car, the oxygen content gradually drops because of human respiration.
No external air will get into the car if the windows are fully wound up.
When the oxygen level drops to 19 per cent, occupants in the car will start to yawn and feel sleepy. This is a reaction of the body trying to get more oxygen.
When the oxygen level drops to 16 per cent, the occupant will be unconscious. If the victim is discovered at this moment, the person can be saved.
When the oxygen level drops to 10 per cent and below, death will occur.
So roll down the window an inch or more to prevent asphyxiation when sleeping in cars.
During asphyxiation, cyanosis (skin turning blue) occurs. In carbon monoxide poisoning, the skin of the victim will be pink and the lips will turn bright red.
WONG SOO KAN
Petaling Jaya, Selangor
