Unseen Passage: Air Pollution

Air pollution is an issue which concerns us all alike. One can willingly choose or reject a food, a drink or a life comfort, but unfortunately, there is little choice for the air we breathe. Everything there in the air is inhaled by all living in those surroundings.

Air pollutant is defined as a substance which is present in an amount exceeding the normal concentrations. It could either be gaseous or a particulate matter. The important and harmful polluting gases are carbon monoxide, carbon dioxide, ozone and oxides of sulphur and nitrogen. The common particulate pollutants are the dust of various inorganic or organic origins. Although, we often talk of the outdoor air pollution caused by industrial and vehicular exhausts, the indoor pollution may prove to be as or a more important cause of health problems.

Recognition of air pollution is relatively recent. It is not uncommon to experience a feeling of ‘suffocation’ in a closed environment. It is often ascribed to the lack of oxygen. Fortunately, however, the composition of air is remarkably constant all over the world. There is about 79 percent nitrogen and 21 percent oxygen in the air the other gases forming a very small fraction. It is true that carbon dioxide exhaled out of lungs may accumulate in a closed and over-crowded place. But such increment is usually small and temporary unless the room is really air-tight. Exposure to poisonous gases such as carbon monoxide may occur in a closed room, heated by burning coal inside. This may also prove to be fatal.

What is more common in a poorly ventilated home is a vague constellation of symptoms described as the sick-building syndrome. It is characterized by a general feeling of malaise, head-ache, dizziness and irritation of mucous membranes. It may also be accompanied by nausea, itching, aches, pains and depression. Sick building syndrome is getting common in big cities with the small houses, which are generally overfurnished. Some of the important pollutants whose indoor concentrations exceed to those of the outdoors include gases such as carbon monoxide, carbon dioxide, oxides of nitrogen and organic substances like spores, formaldehydes, hydrocarbon aerosols and allergens. The sources are attributed to a variety of construction materials, insulations, furnishings, adhesives, cosmetics, house dusts, fungi and the other indoor products.

By-products of fuel combustion are important in houses with indoor kitchens. It is not only the burning of dried dung and fuelwood which is responsible, but also kerosene and liquid petroleum gas. Oxides of both nitrogen and sulphur are released from their combustion.

Smoking of tobacco in a closed environment is an important source of indoor pollution. It may not be high quantitatively, but significantly hazardous for health. It is because of the fact that there are over 3000 chemical constituents in tobacco smoke, which have been identified. These are harmful for human health.

Micro-organisms and allergens are of special significance in the causation and spread of diseases. Most of the infective illnesses may involve more persons of a family living in common indoor environment. These include viral and bacterial diseases like tuberculosis.

Besides infections, allergic and hypersensitivity disorders are spreading fast. Although asthma is the most common form of respiratory allergic disorders, pneumonias are common, but more persistent and serious. These are attributed to exposures to allergens from various fungi, molds, hay and other organic materials. Indoor air ventilation systems, coolers, air-conditioners, dampness, decay, pet animals, production or handling of the causative items are responsible for these hypersensitive-diseases.

Obviously, the spectrum of pollution is very wide and our options are limited. Indoor pollution may be handled relatively easily by an individual. Moreover, the good work must start from one’s own house.

Q. Answer the following:

  1. What is an air pollutant?
  2. In what forms are the air pollutants present?
  3. Why do we feel suffocated in a closed environment?
  4. What is sick building syndrome? How is it increasing?
  5. How is indoor smoking hazardous?
  6. How can one overcome the dangers of indoor air pollution?
  7. Find the words from the above passage which mean the same as the following:
    1. Giddiness (para 4)
    2. Constant (para 8)
    3. Humidity (para 8)


  1. Air pollutant is a gaseous or a particulate matter present in the air in an amount exceeding the normal concentrations.
  2. Air pollutants are present in gaseous form such as carbon monoxide, carbon dioxide, ozone and oxides of sulphur and nitrogen. The pollutants are also in the form of dust of various inorganic or organic origins.
  3. We feel suffocated in a closed environment due to lack of oxygen. Accumulation of carbon dioxide exhaled out of lungs and more exposure to carbon monoxide are also the reasons of suffocation.
  4. Sick building syndrome is characterised by a general feeling of malaise, headache, dizziness and irritation of mucous membrane. It may be accompanied by nausea, itching, aches, pains and depression.
  5. It is increasing due to poorly ventilated and over furnished houses in big cities in which there is high concentration of carbon dioxide, carbon monoxide and oxides of nitrogen and other harmful substances.
  6. Indoor smoking is hazardous in the way that there are 3,000 chemical constituents in tobacco smoke which are harmful to human health.
  7. The houses should be properly ventilated with more and more greenery around them. Smoking of tobacco and burning of coal inside the houses should also be avoided to overcome the dangers of indoor air pollution.
  8. Words are:
    1. Dizziness
    2. Persistent
    3. Dampness

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