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Substances that are Harmful to the Human Respiratory System
Substances that are Harmful to the Human Respiratory System
Cigarette tar
Cigarette tar is one of the toxic substances found in cigarette smoke. Cigarette tar in inhaled air sticks to and kills cells in the air passage such as the thorax, pharynx, epiglottis, larynx, bronchi, bronchioles and alveoli. Cigarette tar also increases the production of mucus and phlegm in the lungs.
Cigarette tar is an example of a substance in cigarette smoke that can cause lung cancer.
Carbon monoxide
Carbon monoxide is usually found in cigarette smoke and exhaust gases of motor vehicles. Carbon monoxide is a colourless and odourless gas. When carbon monoxide diffuses from the alveoli into the blood capillaries, it will combine chemically with haemoglobin to form carboxyhaemoglobin which is a stable compound.
This causes a shortage of oxyhaemoglobin in blood that transports oxygen to the body cells. Due to this shortage, the body cells are unable to produce the required amount of energy through cellular respiration.
Nitrogen dioxide
Nitrogen dioxide that is released into the air is normally produced by the combustion of fuels such as petrol and diesel in motor vehicles. Nitrogen dioxide is a brown-coloured gas with a pungent smell. This gas irritates the air passage and causes cough, difficulty in breathing and asthma.
Sulphur dioxide
Sulphur dioxide that is released into the air is normally produced by the combustion of coal from power stations. Sulphur dioxide is a colourless gas with a pungent smell. It irritates the air passage causing cough, difficulty in breathing, bronchitis and lung cancer.
Haze, dust and pollen
Haze, dust and pollen are solid particles which are fine, light and suspended in the air. The smoke from motor vehicle exhaust, open burning and forest fires produces haze and dust. Pollen released from anthers into the air is carried by the wind over long distances in all directions. Haze, dust and pollen irritate the respiratory system and cause respiratory diseases such as asthma
Respiratory Diseases and their Symptoms
Respiratory Diseases and their Symptoms
Asthma
Asthma is triggered by the presence of dust, pollen, haze, smoke from cigarette and motor vehicle exhaust, open burning and forest fires. Symptoms of asthma include shortness of breath, wheezing and coughing.
Bronchitis
Bronchitis is an inflammation of the bronchus caused by tar and irritants in cigarette smoke. Symptoms of bronchitis include shortness of breath, persistent coughing and insomnia.
Emphysema
Emphysema is the condition of the alveoli in the lungs which are damaged by harmful substances in the air such as irritants in cigarette smoke. Symptoms of emphysema include shortness of breath, pain when breathing and feeling tired from doing even a light task. Emphysema patients cannot be cured but the symptoms of this disease can be controlled.
Lung cancer
Lung cancer is caused by cancer causing chemical substances known as carcinogens. These chemical substances are inhaled during breathing. Cigarette smoke contains various carcinogens, for example tar that causes lung cancer. Symptoms of lung cancer include persistent coughing, blood in the phlegm and feeling pain when breathing. Observe the difference between healthy lungs and the lungs of a cancer patient shown in photograph below.
Effects of Smoking on the Lungs
Effects of Smoking on the Lungs
Experiment 2.2
To study the effects of smoking on the lungs
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