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Air pollution

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A brief information about Air Pollution for Primary and Upper Primary level Teachers

Contents

Introduction

Air pollution is increasing these days.

It has become an universal problem. It has to be inculcated to every young mind that we should try to reduce air pollution.Therefore, this Module focuses on the concept of air pollution for the teachers of Primary and Upper primary levels. The Teacher has to instruct and illustrate the topic in the classroom , therefore, the module tries to delve on the topic with the help of appropriate multimedia support like images, video files.

Definition

Pollution may be defined as an undesirable change in the physical, chemical and biological characteristics of air, water, land etc., that will harmfully affect our life. The agents that pollute the environment are called as pollutants.

Objectives

After going through this module you will be able to

  • understand air pollution.
  • identify the various pollutants causing air pollution.
  • describe the various types of air pollution.
  • understand the effects of air pollution.
  • create awareness about air pollution.
  • appreciate the preventive measures of air pollution.
  • initiate measures to prevent air pollution.
Types of Air Pollution and its Pollutants

Air Pollution: Types

The common atmospheric pollution and its pollutants are displayed in the following table and the types of air pollution based on the locus is described below.

Common atmospheric pollution sources and their pollutants
Sl. No. Category Source Emitting Pollutants
1 Agriculture Open burning Suspended particulate matter, carbon monoxide, volatile organic compounds
2 Mining and quarrying Coal mining; crude oil and gas production; stone quarrying Suspended particulate matter, sulphur dioxide, oxides of nitrogen, volatile organic compounds
3 Power generation Electricity; gas; steam Suspended particulate matter, sulphur dioxide, oxides of nitrogen, carbon monoxide, volatile organic compounds, sulphur trioxide, lead
4 Transport Combustion engines Suspended particulate matter, sulphur dioxide, oxides of nitrogen, carbon monoxide, volatile organic compounds, lead
5 Community service Municipal incinerators Suspended particulate matter, sulphur dioxide, oxides of nitrogen, carbon monoxide, volatile organic compounds, lead

Air Pollution caused by Natural Forces

Volcanic Eruption

Probably the most important natural source of air pollution is volcanic activity, which at times pours great amounts of ash and toxic fumes into the atmosphere, have been related to measurable climatic changes.

The concentrations of different volcanic gases can vary considerably from one volcano to the next. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other principal volcanic gases include hydrogen sulfide, hydrogen chloride, and hydrogen fluoride. A large number of minor and trace gases are also found in volcanic emissions, for example hydrogen, carbon monoxide, halo carbons, organic compounds, and volatile metal chlorides.

Increased carbon dioxide produced by volcanic eruptions with mass extinctions. However, because of the very long term warming effect that occurs with increased atmospheric carbon dioxide (as we see with current climate change) the causal link between global environmental changes and volcanic eruptions has been hard to confirm.

Volcanic Eruption fumes with vast dust particles and ashes

Forest fires

The most common hazard in forests is forests fire. Forests fires are as old as the forests themselves. They pose a threat not only to the forest wealth but also to the entire regime to fauna and flora seriously disturbing the bio-diversity and the ecology and environment of a region.

During summer, when there is no rain for months, the forests become littered with dry senescent leaves and twinges, which could burst into flames ignited by the slightest spark. The Himalayan forests, particularly, Garhwal Himalayas have been burning regularly during the last few summers, with colossal loss of vegetation cover of that region.

Thumb

Forest fires are caused by

Natural causes as well as Man made causes

  • Natural causes- Many forest fires start from natural causes such as lightning which set trees on fire. However, rain extinguishes such fires without causing much damage. High atmospheric temperatures and dryness (low humidity) offer favorable circumstance for a fire to start.
  • Man made causes- Fire is caused when a source of fire like naked flame, cigarette or bidi, electric spark or any source of ignition comes into contact with inflammable material.

Biological agents

Biological agents are present in the air almost everywhere, and are a common factor in office air pollution. They include bacteria, viruses, fungi, pollen, dust mites and other insects, animal dander (tiny scales from hair, feathers, or skin) and molds.

Biological agents can travel through the air and are often invisible. They are usually inhaled, either alone or by attaching themselves to particles of dust and then entering the respiratory system.

Major sources: Offices can be especially vulnerable to microorganisms, because fungi and bacteria find nourishment in inadequately maintained air-circulation systems and in dirty washrooms.

Health effects: When biological agents are allowed to flourish in poorly maintained ventilation systems, severe health problems can result that can be experienced throughout an entire building.

Infectious and noninfectious diseases can be caused by various biological agents. They can make you sneeze, trigger allergic reactions, cause rashes, watery eyes, hoarseness,coughing, dizziness, lethargy, breathing problems, and digestive problems.

People with asthma are especially susceptible to allergic problems caused by biological agents. Their very sensitive airways can react to various allergens and irritants, making breathing difficult.

Indoor Air Pollution

The major reasons for poor indoor air quality in office and home buildings are the presence of indoor air pollution sources; poorly designed, maintained or operated ventilation systems; and uses of the building that were unanticipated or poorly planned for when the building was designed or renovated.

Indoor pollution components

Frequently, no single pollutant is present in unhealthy amounts, yet because there are so many pollutants present, the total effect may be unhealthy. Pollutants most likely to cause problems in the indoor are:

Volatile organic compounds used in Home and office

Volatile organic compounds (VOCs) are released from certain solids or liquids as gases at room temperature. They include a variety of chemicals (benzene, carbon tetrachloride,styrene) which may have both short-term and long-term health effects.

Major sources: Volatile organic compounds can be found in some furniture, paint,adhesives, solvents, upholstery, draperies, carpet, spray cans, clothing, construction materials, cleaning compounds, deodorizers, copy machine toners, felt-tip markers and pens, and correction fluids.

Health effects: Short-term effects include eye, nose and throat irritation; headaches; and nausea. On a long-term basis, exposure to high levels of some of these substances may produce damage to the liver, kidney and the central nervous system.

Asbestos, Formaldehyde

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.

Tobacco, smoke

Secondhand smoke, the smoke from someone else's cigarette, cigar or pipe, contains more than 4,000 chemicals including nicotine, formaldehyde, carbon monoxide, and other known cancer- causing agents.

While smokers themselves face serious health risks from tobacco, it is now clear that even people who don't smoke may be threatened. Exposure to secondhand smoke, also called environmental tobacco smoke, may have certain harmful, possibly even fatal, health effects such as lung cancer and heart disease.

Health effects: Tobacco smoke can irritate eyes, nose and throat and can cause headaches and nausea. The Surgeon General of the United States has concluded that secondhand smoke is definitely dangerous to human health. Involuntary smoking has now been established as a cause of lung cancer in healthy nonsmokers.

Outdoor Air pollution

image:outdoorpollution.jpg

Small particles and ozone come from things like exhaust from cars and factories, smoke and road dust. When inhaled, outdoor pollutants can aggravate the lungs, and can lead to chest pain, coughing, shortness of breath and throat irritation. Outdoor air pollution may also worsen chronic respiratory diseases, such as asthma. On days when ozone air pollution is highest, ozone has been associated with 10-20% of all respiratory hospital visits and admissions. The remarkable out door air pollutants are:

Automobile exhausts

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Automobile Exhausts

Automobile exhausts cause sever pollution in the environment. The produce a large amount of Carbon monoxide and Carbon-di-oxides also Lead oxides with some amount of Unsaturated hydro carbons.

Carbon mono Oxide (CO)is a colourless, odourless gas that is produced by the incomplete burning of carbon-based fuels including petrol, diesel, and wood. It lowers the amount of oxygen that enters our blood . It can slow our reflexes and make us confused and sleepy.

Carbon dioxide (CO2)is the principle greenhouse gas.

Industrial smokes and fumes

Industrial smokes

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Industrial Smokes: A major pollutant

Like wise the Automobile exhaust gases, The industrial smokes and fumes also consists of Large amount of various pollutants such as Suspended particulate matter, Oxides of Carbon, Nitrogen, Sulfur and Lead etc., also other organic by products.

Fly ash and Smog The industrial smoke and natural disasters such as volcanic eruptions make a larger production of fly ash in the atmosphere. The smog also formed due to higher concentration of smoke with fog. The impacts and effects of the fly ash and smog are illustrated in the following session.

Pollutants involved

Pollutants

Carbon monoxide (CO) It is a colourless, odourless gas that is produced by the incomplete burning of carbon-based fuels including petrol, diesel, and wood. It is also produced from the combustion of natural and synthetic products such as cigarettes. It lowers the amount of oxygen that enters our blood . It can slow our reflexes and make us confused and sleepy.

Carbon dioxide (CO2) is the principle greenhouse gas emitted as a result of human activities such as the burning of coal, oil, and natural gases.

Chloroflorocarbons (CFC) Widely used in refrigeration and coolant industries. These CFCs causes Green house effect. When released into the air, CFCs rise to the stratosphere, where they come in contact with few other gases, which leads to a reduction of the ozone layer that protects the earth from the harmful ultraviolet rays of the sun. Oxides of Sulfur, Nitrogen and Lead. causes smog and acid rain. It is produced from burning fuels including petrol, diesel, and coal. Nitrogen oxides can make children susceptible to respiratory diseases in winters.

Sulphur dioxide (SO2) is a gas produced from burning coal, mainly in thermal power plants. Some industrial processes, such as production of paper and smelting of metals, produce sulphur dioxide. It is a major contributor to smog and acid rain. Sulfur dioxide can lead to lung diseases.

The oxides of lead and mercury causes cancer among animals and human.

Suspended particulate matters. Suspended particulate matter (SPM) consists of solids in the air in the form of smoke, dust, and vapour that can remain suspended for extended periods and is also the main source of haze which reduces visibility. The finer of these particles, when breathed in can lodge in our lungs and cause lung damage and respiratory problems.

Bio-products such as Pollens, Spores etc., These causes allergic, nausea to human. Also act as vector for many microbes.

Impacts and Effects of Air Pollution

Air Pollution: Impacts and Effects

The effects and impacts of air pollution is discussed under the following heads:

  • Smog formation
  • Acid rain
  • Fly ash problems

Formation of Smog

The term smog was first used in 1905 by Dr H A Des Voeux to describe the conditions of fog that had soot or smoke in it. The effects of smog on human health were evident, particularly when smog persisted for several days. Many people suffered respiratory problems and increased deaths were recorded, notably those relating to bronchial causes.

Smog:some basic Information

The industries and the households relied heavily on coal for heating and cooking. Due to the burning of coal for heat during the winter months, emissions of smoke and sulphur dioxide were much greater in urban areas than they were during the summer months. Smoke particles trapped in the fog gave it a yellow/black colour and this smog often settled over cities for many days.

Acid rain

Formation of acid rain

Acid rain is created when gases such as nitrogen oxide (NOx) and sulfur oxide (SOx), generated in the burning of fossil fuels such as coal and oil, react in the atmosphere with sunlight to produce acids such as nitric and sulfuric acid. These acids dissolve in rain to become acid rain.

At what acidity (pH) level is rain considered "acid rain"?

When we observe acid rain, acidity is measured in units called pH, which indicate the acidity of an aqueous solution. pH is a measure of the concentration in the aqueous solution of hydrogen ions: pH 7 indicates neutral acidity, with higher pH numbers signifying alkalinity and smaller numbers denoting an acidic solution. In Japan, rain which registers pH 5.6 or less is considered acid rain; some 80-90% of the rain that falls in Japan in a year is acid rain.

The Effects of Acid Rain

Effect of acid rain on a forest, Jizera Mountains, Czech Republic

The problem is even more serious in North America and Europe. In those regions, forests are withering and lakes becoming uninhabitable to fish, and stone structures such as buildings and bronze statues are being damaged by corrosion.

Fly ash problems

Fly Ash


Thermal power generation through coal combustion produces minute particles of ash that causes serious environmental problems.

Commonly known as fly ash, these ash particles consist of silica, alumina, oxides of iron, calcium, and magnesium and toxic heavy metals like lead, arsenic, cobalt, and copper.

This poses problems in the form of land use, health hazards, and environmental dangers.

Today, fly ash bricks can be used as a building material.

Fly Ash

Air Pollution: Preventive and Remedial measures

Preventive and Remedial measures for Air Pollution

  • Keeping the environment clean and managing the wastes with the Guide lines of respective Government.
  • The Exhausts from the Automobiles and workshop machinery should be controlled.
  • The ISO standards must be followed strictly for Industrial usage.

What you can do to reduce air pollution ?

  • Encourage your family to walk to the neighbourhood market.
  • Whenever possible take your bicycle.
  • Don’t let your father drop you to school, take the school bus.
  • Encourage your family to form a car pool to office and back.
  • Reduce the use of aerosols in the household.
  • Look after the trees in your neighbourhood.
  • Begin a tree-watch group to ensure that they are well tended and cared for.
  • Switch-off all the lights and fans when not required.
  • If possible share your room with others when the air conditioner, cooler or fan is on.
  • Do not burn leaves in your garden, put them in a compost pit.
  • Make sure that the pollution check for your family car is done at regular intervals
  • Cars should, as far as possible, be fitted with catalytic converters.
  • Use only unleaded petrol.
Evaluation

Evaluation

The Teacher can frame up simple questions in different formats using Flash cards, Oral, and Multiple Choice Questions etc., stressing the objective of the module he taught.

Some SIMPLE (SAMPLE) QUESTIONS:

  1. What is pollution ?
  2. What are the contents of atmosphere ?
  3. What is the use of Carbon-di-oxide ?
  4. How the carbon di oxide can be a pollutant ?
  5. What are the air pollutants found in your home ?
  6. Who will be the responsible for pollution by a car or Motor cycle ?
  7. How do you prevent air pollution from your Home ?
  8. What is fly ash ?
  9. What is a smog ?
  10. What is a suspended particulate matter ?
  11. What are the gases evolved from coal burning ?
  12. What is called acid rain ?

SAY TRUE OR FALSE:

  1. The Carbon-di-oxide is an Primary gas causing Green House effect.
  2. The acid rain is caused by pollutants of water.
  3. The air pollution can contaminate the agriculture and architecture through acid rain.
  4. The fly ash can be made useful for construction engineering.
  5. The smog can affect the Ozone layer.


Final Verdict

Summary

The teacher narrate the things described in this module and receive the feed back from evaluation and summarizes the learning experiences regarding with the air pollution.

For the detailed text about our environment from an Upper primary level text book ( Text book on Science VIII standard, Tamil Nadu Text Book Corporation, Chennai-6.) kindly click here.

Our Environment

Our Environment

References

Science Text book for Standard VIII. p200-218, Tamil Nadu Text Book Corporation, College Road, Chennai-6.

http://edugreen.teri.res.in/explore/air/air.htm

http://en.wikipedia.org/wiki/Air_pollution

http://healthandenergy.com/air_pollution_causes.htm

http://edugreen.teri.res.in/explore/air/air.htm

http://www.youtube.com/watch?v=UcWpkWBX04E

T.Madhavan, Lecturer, DIET, Puducherry.

--Madhavan 14:49, 27 August 2009 (IST)

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