Sunday, 26 January 2014


Air is the mixture of gases that surround earth due to its gravitational pull. It is colourless, odourless and tasteless mixture that forms earth’s atmosphere. It contains Nitrogen (79.1%), Oxygen (20.0%), Carbon dioxide (0.03%) and traces of inert gases like argon, krypton, xenon, neon, helium, ammonia, ozone, water vapour and suspended particles (0.07%).

We need air to perform certain vital life functions. All human beings and animals breathe in Oxygen and breathe out Carbon dioxide. Plants breathe in Carbon dioxide and breathe out oxygen in the day time to manufacture their own food through Photosynthesis. But they follow the pattern of animals at the night. Without Air there would be no transmission of sound and radiation waves, no burning of fire and cycle of seasons.


When the natural composition of air is altered to such an extent, so as to make it harmful for living creatures primarily due to human activities, air is said to be ‘polluted’. Any substance that causes pollution is called pollutant. Pollutants can be solid, liquid or gaseous substance.

Air is polluted by natural ways of volcanic eruptions, forest fires, pollen from plants etc. However, nature has a way of balancing itself. Our concern here is man caused pollution which is looming largely as a threat to modern civilization. Pollution can be INDOOR as well as OUTDOOR:

INDOOR AIR POLLUTION refers to the physical, chemical, and biological characteristics of air in the indoor environment within a home, building, or an institution or commercial facility. Indoor air pollution is a concern in the developed countries, where energy efficiency improvements sometimes make houses relatively airtight, reducing ventilation and raising pollutant levels. Indoor air problems can be subtle and do not always produce easily recognized impacts on health. Tobacco smoke, cooking and heating appliances, and vapors from building materials, paints, furniture, etc. cause pollution inside buildings.

Volatile organic compounds originate mainly from solvents and the main indoor sources are perfumes, hair sprays, furniture polish, glues, air fresheners, moth repellents, wood preservatives, and many other products used in the house. Their main health effect is the imitation of the eye, nose and throat. In more severe cases there may be headaches, nausea and loss of coordination. In the long term, some of the pollutants are suspected to damage to the liver and other parts of the body.

Tobacco smoke generates a wide range of harmful chemicals and is known to cause cancer. It is well known that passive smoking causes a wide range of problems to the passive smoker (the person who is in the same room with a smoker and is not himself/herself a smoker) ranging from burning eyes, nose, and throat irritation to cancer, bronchitis, severe asthma, and a decrease in lung function.

Biological pollutants include pollen from plants, mite, hair from pets, fungi, parasites, and some bacteria. Most of them are allergens and can cause asthma, hay fever, and other allergic diseases.

Formaldehyde is a gas that comes mainly from carpets, particle boards, and insulation foam. It causes irritation to the eyes and nose and may cause allergies in some people.

Asbestos is mainly a concern because it is suspected to cause cancer.

Radon is a gas that is emitted naturally by the soil. Due to modern houses having poor ventilation, it is confined inside the house causing harm to the dwellers.

OUTDOOR AIR POLLUTION is the pollution that occurs outside homes through automobiles, industrial emissions etc.

1) Oxides of sulphur 2) Oxides of Nitrogen 3) Suspended Particulate Matter 4) Carbon Monoxide 5) Lead 6) Benzene 7) Hydrocarbons

Health impacts of air pollution depend on pollutant type, its concentration in air, interaction with other pollutants, and length of exposure and individual vulnerability.

Air Pollution has both acute and chronic effects on Human health. It has both long term and short term effects. It may range from minor irritation to most chronic respiratory problems.

Ø  Aggravated cardiovascular and respiratory problems
Ø  Burden on heart and lungs, causing them to work harder to supply the body with oxygen
Ø  Damage the cells in respiratory organs
Ø  Damage to deeper portions of lungs, even after symptoms of coughing or sore throat disappear
Ø  Wheezing, chest pain, dry throat, headache or nausea
Ø  Increased reactivity to allergens and particles
Ø  Eye irritation
Ø  Reduced body immunity to infection and increased fatigue

Ø  Accelerated ageing of lungs and loss of lung capacity
Ø  Decreased lung function
Ø  Diseases like, asthma, bronchitis, emphysema and cancer
Ø  Is a potential cause of human mortality

1. Acute respiratory infections (ARI) in children:   ARI in children under 5 years in India cause: 13% of deaths; 11% of NBD; 24% of NBD for children under 5 years (NBD- National Burden of Disease)
ARI is the largest single disease category for India, accounting for about one-ninth of the national burden. For the world as a whole, ARI is also the largest category, accounting for about 8.5% of the global burden.
Acute respiratory infections as pneumonia, is one of the chief killers of children in Developed Countries. It is well known to be enhanced by exposure to urban air pollutants and indoor environmental tobacco smoke at levels of pollution that are some 10-30 times less than that typically found in villages.
A recent study of 642 infants conducted in urban slums of New Delhi. The incidence of acute respiratory infection was more in highly polluted areas than less polluted areas. In India, children have to bear the double the burden of diseases that have persisted for generations as well as of new diseases caused by various environmental factors.

Asthma: Asthma causes: 0.2% of deaths; 0.5% of NBD in India. Although Asthma rates are officially low in India, there is some recent evidence that the true prevalence is higher than previously thought. Associated with urban outdoor pollution and ETS (Environmental Tobacco smoke), typical solid-fuel indoor smoke exposures are much higher. Undoubtedly, the rates of Asthamatic patients have been increasing; it might be due to increase in the environmental pollution. 

2. Chronic obstructive pulmonary disease: Today in developed countries, nearly all cases of COPD are attributable to tobacco smoking. Undoubtedly, smoking is also a significant factor in COPD incidence among LDC (Less Developed Countries) men. In India, even though relatively few rural women smoked during the past decades, COPD in rural women today is not uncommon. Chronic obstructive lung disease, for which tobacco smoking is the major risk factor remaining in the developing countries is known to be an outcome of excessive exposure to air pollution.

3. Cancer: There are many chemicals in biomass smoke, which are carcinogenic in nature. In recent study in Japan on the other hand, found that women aged 30 years old cooking with wood fuel have an 80% increased chance of having lung cancer in later life.

4. Tuberculosis: India has a larger fraction of its national burden of disease attributable to TB than any other region, although the actual risk per person is less than that in Sub-Saharan Africa. A large scale survey in India reported that women using bio fuels were three times more likely to have tuberculosis than women using cleaner fuels.

5. Blindness: India has a larger burden of blindness than any other major region of the world. Indeed, globally, one out of three cataracts occurs in India where they are responsible for 80% of blindness in the country. One case-control study in Delhi found an excess cataract risk of about 80% among people using biomass fuel.  

The Health Information of India reports show that environmental reasons are increasingly responsible for increased mortality in women and children (see graphs: What kills India’s children). According to the report, 55 percent of child mortality in India is due to conditions originating in the prenatal period. A significant proportion of the tables are strongly related to environmental causes. 

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