Effects on Health - Consequences of Air Pollution
Since the air pollutants are inhaled they attack various parts of the respiratory system on their route to air sacs. Once they reach the blood, they circulate throughout the body and reach the target organs. The extent of damage depends upon a particular pollutant, its concentration in the air and exposure time. Our body's defence mechanism helps to eliminate them. However, exposure to high level overloads and degrades the body's defence mechanism.
Evidences show that air pollutants are linked with respiratory and some other diseases in human beings. Sulphur dioxide is a major contributor to lung diseases. It causes irritation to nose and mucous lining. shortness of breath, tissue fluid accumulation, swelling (edema) and bronchospasm. These are the acute effects. Long- term exposure may result in respiratory diseases like-chronic bronchitis, aggravated asthma, emphysema, pulmonary fibrosis and increased stress on heart. Particulate matter potentiates the effect of SO2. The gas settles on the particles and reaches the deeper parts of respiratory system. Hence the toxicity of low concentration of SO2 can significantly increase.
The exhaust of buses, trucks and two wheelers causes eye and lung irritation. This is due to oxide of nitrogen inhalation in large amounts may give rise to gum inflammation, internal bleeding, pneumonia and cancer. NOx oxidises lipids in the cells. So the cell membranes are disrupted leading to respiratory edema.Carbon monoxide is one of the most poisonous gases. When it enters blood circulation it competitively inhibits the combining of oxygen with haemoglobin. Its affinity for haemoglobin is more than 200 times that of oxygen. That is why even extremely low levels of CO are not safe. High concentrations of CO slow down physical and mental activities and may cause asphyxiation, heart and brain damage.
Ozone and peroxyacyl nitrate (PAN) have a remarkable degree of biological activity. Even very small concentration of PAN or ozone causes irritation of eyes. Ozone causes cough, headache, weakness, difficulty in breathing, bleeding, dry throat and constriction of respiratory passage and weakens the lung tissues.