Smoking is hazardous to health. When cigarette smokers inhale the cigarette smoke into their lungs, a number of toxic substances contained in the smoke enter the body.
Toxic chemicals in cigarette smoke
Cigarette smoke contains over 1000 different chemicals , about sixteen of which are carcinogens ( 致癌物質 ) .The main carcinogens are a group of sweet-smelling chemicals usually referred to as ' tar '( 焦油 ).Cigarette smoke also contains nicotine and carbon monoxide. Each of these ingredients has its own effect on the body.
Lung cancer ( 肺癌 )
Cigarette smoke contains tar which consists of chemicals which cause cancer. A filter will not remove all the tar. These are described at carcinogens. Carcinogenic chemicals make the cells of various tissues reproduce in an uncontrolled way. Affected tissue grows but cannot function in the normal way. When this happens to lung tissue, people often die of lung cancer.
Bronchitis
Substances in cigarette smoke also irritate the walls of the trachea and the bronchial tubes. Extra mucus is produced which clogs up the respiratory passages. This makes breathing difficult and leads to a 'smoker's cough'. Very often, the bronchial tubes become infected and the disease lasts a long time instead of clearing up in a few days. This is called chronic bronchitis.
Emphysema( 肺氣腫 )
Cigarette smoke contains acidic and irritant substances. These substances attack the sensitive walls of the alveoli. The alveoli break down and this reduces the surface area in the lungs over which gaseous exchange can occur. This disease is called emphysema. Smokers suffering in this way become very short of breath.
Although smoking mainly affects the lungs, it has other harmful or unpleasant effects:
It gives your breath and clothes an unpleasant smell.
- It increases the risk of coronary thrombosis (heart attack) and other diseases of the blood system.
- It can cause cancer of the mouth or throat.
- It reduces your senses of taste and smell.
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