Definition and Types of Pollution Hazards

Introduction

Pollution can be defined as "an undesirable change in the physical, chemical or biological characteristics of air, water and soil that may create a hazard to the health, safety or welfare of living species. -K.C. Agrawal

There are different types of pollution hazards on health. Such as:

• Air pollution 
• Noise pollution
• Land pollution etc.

Air Pollution

The air that makes up a person's immediate surroundings is essential for all life forms. In addition to providing life-sustaining oxygen, air and atmospheric conditions have other uses. The unique senses of hearing and smell work through air-transmitted stimuli, and disease agents may be transferred by air. Air contact cools the human body. The Earth's temperature rises as a result of these greenhouse gases' ability to trap heat inside the atmosphere. When fossil fuels are used, more hazardous gases are emitted. These gases have serious detrimental consequences on both human health and the environment. The "Big Six" air pollutants, which are gases, are as follows:

• Carbon Dioxide
• Hydrocarbons (Benzene, Terpene, etc.)
• Particulates
• Nitrogen Oxide
• Carbon Monoxide
• Sulfur Oxide

Sources of Air Pollution

The air becomes polluted in different ways:

Automobiles: Motor vehicles are a major source of air pollution throughout the urban areas. They produce hydrocarbons, carbon monoxide, lead, nitrogen oxides & particulate matter. In strong sunlight, certain of these hydrocarbons & oxides of nitrogen may be converted in the atmosphere into "photochemical" pollutants of oxidizing nature.

Industries : Industries produce large amounts of pollutants into the atmosphere. Many industries such as, chemical industries, oil refineries etc, have been established. Petrochemical industries generate hydrogen fluoride, hydrochloric acid & organic halides. Many industries discharge carbon monoxide, carbon dioxide, ozone, and hydrogen sulphide and sulphur dioxide. Industries discharge their wastes from high chimneys at high temperature & high speed.

Domestic Sources: Domestic combustion of coal, wood or oil is a major source of smoke, dust, and sulphur dioxide & nitrogen oxides.

Tobacco Smoke: The most direct & important source of air pollution affecting the health of many people is tobacco smoke. Even those who do not smoke may inhale the smoke produced by others (passive smoking).

Miscellaneous: These include burning refuse, incinerator, pesticide spraying, natural sources (e.g. wind borne dust, fungi, molds. bacteria) & nuclear energy programmes. All these contribute to air pollution.

Indoor Air Pollution

Indoor air pollution is one of the four most critical global environmental problems, probably exposes more people worldwide to important air pollutants than does pollution in outdoor air. Smokey houses in Nepal have peak level of overline 10 ,000 m/m^ 3 or more. Women & young children suffer the greatest exposure.

Examples of Air Pollution

• Carbon monoxide gas (poisonous) in mines or garages (from petrol exhaust).
• Sulphur dioxide gas (in many industries). which turns into sulphuric acid & destroys buildings in time.
• Bad odours from decomposing refuse, excreta or dead animals.
• Bad odours from industrial manufactures, e.g. leather or soap works.

Effects of Air pollution/health Hazards of Air Pollution

The effects of air pollution on people can lead to health problems. This might happen right away or at a later time. Acute bronchitis is the initial side effect that the respiratory system experiences. If the air pollution is severe enough, it might possibly cause instantaneous asphyxia death.

Chronic bronchitis, lung cancer, bronchial asthma, emphysema, and respiratory allergies are the delayed effects most frequently associated with air pollution.

Lead poisons many bodily systems and is especially harmful to children's developing brains and nervous systems.

Prevention & Control of Air Pollution

The control of air pollution is ultimately an engineering problem. The WHO has recommended the following procedures for the prevention & control of air pollution:

Containment: That is, prevention of escape of toxic substances into the ambient air. Containment can be achieved by a variety of engineering methods such as enclosure, ventilation & air cleaning.

Replacement: That is, replacing a technological process causing air pollution by a new process that does not. Increased uses of electricity, natural gas & central heating in place of coal have greatly helped in smoke reduction.

Dilution: Dilution is valid so long as it is within the self-cleaning capacity of the environment. For eg, same air pollutants are readily removed by vegetation. The establishment of "green belts" between industrial & residential areas is an attempt at dilution.

Legislation: Air pollution is controlled in many countries by suitable legislation, eg. Clean Air Acts. Legislation covers such matters as height of chimneys, power to local authorities to carry out investigations, research & education concerning air pollution.

International Action: To deal with air pollution on a world-wide scale, the WHO has established an international network of laboratories for the monitoring & study of air pollution. These centers will issue warnings of air pollution where & when necessary.

Education of People: In Nepal, a number of houses use wood, charcoal, coal as domestic fuel for cooking & other related purpose. This produces smoke & this contributes significantly to air pollution. Hence educating people about the use of smokeless stoves essential to reduce air pollution.

Noise Pollution

in a very noisy People are living today in a environment. Noise is an unwanted sound at an unwanted place, at the wrong time, perhaps by an unwanted person or equipment. Human is living is an increasingly noisy environment. 

Properties of Noise

Loudness: Loudness or intensity depends upon the amplitude of the vibrations which initiated the noise. The loudness of noise is measured in decibels. Normal conversation produces a noise of 60-65 dB; whispering 20- 30 dB; heavy street traffic, 60-80 dB; & about 120 dB. A daily exposure up to 85 dB is about the limit people can tolerate without substantial damage to their hearing. 

Frequency: The frequency is denoted as Hertz (Hz). One Hz is equal to one wave per second. The human ear can hear frequencies from about 20-20,000 Hz, but this range is reduced with age & other subjective factors. The range of vibrations below 20 Hz are intra-audible & those above 20,000 Hz ultra- sonic. Many animals (e.g. dogs) can hear sounds inaudible to the human ear.

Sources of Noise Pollution

The sources of noise are many & varied. Those are:

• Automobiles
• Factories
• Industries
• Air-craft
• Trains (acute near railway junctions)
• Traffic in this area
• Bus terminuses & airports.
• Use of pressure horns
• Recreational noise of loudspeakers with full volume during celebrations particularly at night are other sources of noise production
• The domestic noises from the mixer grinder, radios, transitory TV set, vacuum cleaner etc.
• Barking of dogs

Prevention & Control of Noise

• Careful Planning of Cities: In planning cities, measures should be taken to reduce noise include:
  • The separation of areas concerned with industry and transport.
  • Division of the city into zones with separation of areas concerned with industry and transport.

  • The separation of residential areas from the main streets by means of wide green belts.

  • Widening of the main streets to reduce the level of noise.

  • House fronts should lie not less than 15 meters from the road and the intervening space should be thickly planted with trees and bushes.

• Control of Vehicles
  • Heavy vehicles should not be routed in narrow streets.
  • Vehicular traffic on residential streets should be reduced.
  • Indiscriminate blowing of the born and use of pressure horn should be prohibited.
• To Improve Acoustic

From the acoustic standpoint the best environment is construction of detached buildings rather than a single large building or one that is continuous. Installations that produce noise or disturb the occupants within dwellings should be prohibited. Buildings should be sound proof where necessary.

• Industries and Railways: Definite area must be earmarked, outside residential areas for industries, for railways, marshalling yards and similar installations. If it is not possible, protective green belts must be laid down between the installations and residential areas.
• Protection of Exposed Person: Hearing protection is recommended for all workers who are consistently exposed to noise louder than 85 decibels in the frequency bands above 150 Hz. Periodical audiogram check- ups and use of ear plugs, earmuffs are also essential as the situation demands.
• Legislation: Legislation providing for controls which are applicable to a wide variety of sources. Workers have the right to claim compensation if they have suffered a loss of ability to understand speech.
• Education: People's participation can be taken by education, and then through all available media is needed to highlight the importance of noise as a community hazard in noise control programmes.

Land Pollution

Land pollution basically refers to the soil and land surface of the Earth being contaminated by harmful agricultural practices, the indiscriminate dumping of industrial waste, the exploitation of minerals, and the dumping of urban waste. Along with the soil itself being polluted, land pollution also includes waste and visible litter.

Causes of Land Pollution

• Land pollution is caused by farms because they allow manure to collect, which leaches into the nearby land areas. The composting and pesticides are the reasons that influence the environment. 
• Oil field is a part of the environment pollution The industries are developing. Also there are a lot of oil factories which are building. 
• Solid waste: Semisolid or solid matters that are created by human or animal activities, and which are disposed because they are hazardous or useless are known as solid waste. 

Effects of Land Pollution

Land pollution can affect wildlife, plants, and humans in a number of ways, such as:

• Cause problems in the respiratory system Cause problems on the skin.
• Lead to birth defects.
• Cause various kinds of cancers.
• Bad smell from the polluted soil affects the surrounding environment.

The toxic materials that pollute the soil can get into the human body directly by:

• Coming into contact with the skin.
• Being washed into water sources reservoirs and rivers.
• Eating fruits and vegetables that have been grown in polluted soil.
• Breathing in polluted dust or particles.

Control Measures

The following measures can be used to control land pollution:

• Anti-litter campaigns can educate people against littering.
• Organic waste can be dumped in places far from residential areas.

Inorganic materials such as metals, glass and plastic, but also paper, can be reclaimed and recycled.

• People should be educated and made aware about the harmful effects of littering.
• Items used for domestic purposes ought to be reused or recycled.
• Personal litter should be disposed properly.
• Organic waste matter should be disposed in areas that are far away from residential places.
• Inorganic matter such as paper, plastic, glass and metals should be reclaimed and then recycled.
• Insecticides and pesticides should be used wisely.

Water Pollution

The polluting of water bodies is known as water pollution (e.g. lakes, rivers, oceans and groundwater).

When dangerous substances are released into water bodies either directly or indirectly without being adequately treated to eliminate them, water pollution results.

The plants and animals that inhabit these bodies of water are impacted by water pollution. The effect harms not only specific species and populations but also the broader natural biological communities almost always.

The biggest health hazard in the world, dirty water continues to endanger both public health and quality of life.

Water sources are getting scarce due to climate change and global warming. Similarly, water resources are getting polluted day by day due to human activities. Water pollution is standing as a biggest challenge for the developing countries. Poor countries of the world are bearing human and financial loss due to water pollution.

Causes of Water Pollution

Soils and groundwater contain the residue of human agricultural practices and also improperly disposed of industrial wastes. The main causes of water pollution are namely; Industrial waste, Household waste and sewage and drainage. The other causes can be listed below.

• Transports and chemical reaction of water pollutants.
• Chemicals and other contaminants.
• Macroscopic pollution.