question_answer

Read the passage given below and answer the questions that follow:

1. 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. All, is there in the air is inhaled by one and all living in those surroundings.

2. 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 dusts 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.

3. 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 an increase 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.

4. What is more common in a poorly ventilated home is a vague constellation of symptoms described as the sick-building syndrome. It is characterised 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 commoner in big cities with the small houses, which are generally over- furnished. 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 other indoor products.

5. 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.

6. 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.

7. 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.

8. 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 hypersensitivity - diseases.

9. 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,

(a)      (i) What is an air pollutant?

 

Answer:

Air pollutant is defined as a substance which is present in the air while normally, it is not present in an amount exceeding the normal concentrations.