Document 2
Document 2
Document 2
OF
PACHAIYAPPA’S TRUST
B.SC II YEAR
DEPARTMENT OF ADVANCED ZOOLOGY & BIOTECHNOLOGY
NAME : BANULAKSHMI P
REGISTER NO. : 222105374 SIGNATURE OF THE EXAMINER
YEAR : 2022 - 23
Air pollution occurs when gases, dust particles, fumes (or smoke) or odour are
introduced into the atmosphere in a way that makes it harmful to humans, animals and
plant. Air pollution threatens the health of humans and other living beings in our
planet.
It creates smog and acid rain, causes cancer and respiratory diseases, reduces the
ozone
layer atmosphere and contributes to global warming.
In this industrial age, air pollution cannot be eliminated completely, but steps
can be taken to reduce it. The government has developed, and continues to develop,
guidelines for air quality and ordinances to restrict emissions in an effort to control air
pollution. On an individual level, we can reduce our contribution to the pollution
problem by carpooling or using public transportation. Additionally, buying energy-
efficient light bulbs and appliances or otherwise reducing our electricity use will
reduce
the pollutants released in the production of electricity, which creates the majority of
industrial air pollution.
Introduction
Air pollution is the introduction into the atmosphere of chemicals,
particulates, or biological materials that cause discomfort, disease, or death to
humans,
damage other living organisms such as food crops, or damage the natural
environment
or built environment.
A substance in the air that can be adverse to humans and the environment
is known as an air pollutant. Pollutants can be in the form of solid particles, liquid
produced from a process, such as ash from a volcanic eruption, the carbon
monoxide gas from a motor vehicle exhaust or sulphur dioxide released from
factories. Secondary pollutants are not emitted directly. Rather, they form in the air
when primary pollutants react or interact.
An example of a secondary pollutant is ground level ozone – one of
the many secondary pollutants that make up photochemical smog. Some
pollutants may be both primary and secondary: that is, they are both emitted directly
and formed from other primary pollutants.
Major primary pollutants produced by human activity include:
Sulphur oxides (SOx) - especially sulphur dioxide, a chemical compound with the
formula SO2. SO2 is produced by volcanoes and in various industrial processes.
Since coal and petroleum often contain sulphur compounds, their combustion
generates sulfur dioxide. Further oxidation of SO2, usually in the presence of a
catalyst such as NO2, forms H2SO4, and thus acid rain. This is one of the causes for
concern over the environmental impact of the use of these fuels as power sources.
Nitrogen oxides (NOx) - especially nitrogen dioxide are expelled from high
vegetation, and sea spray. Human activities, such as the burning of fossil fuels in
vehicles, power plants and various industrial processes also generate significant
amounts of aerosols. Averaged over the globe, anthropogenic aerosols—those
made by human activities – currently account for about 10 percent of the total
amount of aerosols in our atmosphere. Increased levels of fine particles in the air
are linked to health hazards such as heart disease, altered lung function and lung
cancer.
Ground level ozone (O3) formed from NOx and VOCs. Ozone (O3) is a key
constituent of the troposphere. It is also an important constituent of certain regions
of the stratosphere commonly known as the Ozone layer. Photochemical and
chemical reactions involving it drive many of the chemical processes that occur in
the atmosphere by day and by night. At abnormally high concentrations brought
about by human activities (largely the combustion of fossil fuel), it is a pollutant,
and a constituent of smog.
Natural sources
Dust from natural sources, usually large areas of land with few or no
vegetation.
Methane, emitted by the digestion of food by animals, for example cattle.
Radon gas from radioactive decay within the Earth's crust. Radon is a
colorless, odorless, naturally occurring, radioactive noble gas that is formed from the
decay of radium. It is considered to be a health hazard. Radon gas from natural
sources
can accumulate in buildings, especially in confined areas such as the basement and
it is the second most frequent cause of lung cancer, after cigarette smoking.
Smoke and carbon monoxide from wildfires.
fatalities may be caused by using pesticides and other chemical sprays indoors
without
proper ventilation.Carbon monoxide (CO) poisoning and fatalities are often caused
by
faulty vents and chimneys, or by the burning of charcoal indoors.
Biological sources of air pollution are also found indoors, as gases and
airborne particulates. Pets produce dander, people produce dust from minute skin
flakes and decomposed hair, dust mites in bedding, carpeting and furniture produce
enzymes and micrometer-sized fecal droppings, inhabitants emit methane, mold
forms in walls and generates mycotoxins and spores, air conditioning systems can
incubate Legionnaires' disease and mold, and houseplants, soil and surrounding
gardens can produce pollen, dust, and mold. Indoors, the lack of air circulation
allows
these airborne pollutants to accumulate more than they would otherwise occur in
nature.
Health Effects
Air pollution is a significant risk factor for multiple health conditions
including respiratory infections, heart disease, and lung cancer, according to the
WHO. The health effects caused by air pollution may include difficulty in
breathing,
wheezing, coughing, asthma and aggravation of existing respiratory and cardiac
conditions. These effects can result in increased medication use, increased doctor
or
emergency room visits, more hospital admissions and premature death.
The human health effects of poor air quality are far reaching, but
principally affect the body's respiratory system and the cardiovascular system.
Individual reactions to air pollutants depend on the type of pollutant a person is
exposed dangerous of , the individual's health status and genetics.
The most common sources of air pollution include particulates, ozone,
nitrogen dioxide, and sulfur dioxide. Both indoor and outdoor air pollution have
caused approximately 3.3 million deaths worldwide. Children aged less than five
years that live in developing countries are the most vulnerable population in terms
of total deaths attributable to indoor and outdoor air pollution. The World Health
Organization states that 2.4 million people die each year from causes directly
attributable to air pollution, with 1.5 million of these deaths attributable to indoor
air
pollution. The worst short term civilian pollution crisis in India was the 1984
Bhopal
Disaster.
Leaked industrial vapours from the Union Carbide factory, belonging to
Union Carbide, Inc., U.S.A., killed more than 25,000 people outright and injured
anywhere from 150,000 to 600,000. The United Kingdom suffered its worst air
pollution event when the December 4 Great Smog of 1952 formed over London. In
six days more than 4,000 died, and 8,000 more died within the following months.
An
accidental leak of anthrax spores from a biological warfare laboratory in the former
USSR in 1979 near Sverdlovsk is believed to have been the cause of hundreds of
civilian deaths.
Around the world, children living in cities with high exposure to air
pollutants are at increased risk of developing asthma, pneumonia and other lower
respiratory infections. Because children are outdoors more and have higher minute
ventilation they are more susceptible to the dangers of air pollution. Risks of low
initial birth weight are also heightened in such cities.
Environmental Effects
Poisonous air pollutants (toxic chemicals in the air) can form acid rain. It
can also form dangerous ground level ozone. These destroy trees, crops, farms,
animals and continue to make water bodies harmful to humans and animals that live
and depend on water.
Economical Effects The effect of air pollution on the economy may be a
derived one. In simple language, the economy thrives when people are healthy, and
business that depends on cultivated raw
materials and natural resources are running at full efficiency.
.
Control devices
The following items are commonly used as pollution control devices by
industry or transportation devices. They can either destroy contaminants or
remove
them from an exhaust stream before it is emitted into the atmosphere.
Mechanical collectors (dust cyclones, multi-cyclones)
Electrostatic precipitators: An electrostatic precipitator (ESP),
or electrostatic air cleaner is a particulate collection device that removes particles
from a flowing gas (such as air) using the force of an induced electrostatic charge.
Electrostatic precipitators are highly efficient filtration devices that minimally
impede the flow of gases through the device, and can easily remove fine
particulates
such as dust and smoke from the air stream.
Bag houses: Designed to handle heavy dust loads, a dust collector consists
of a blower, dust filter, a filter-cleaning system, and a dust receptacle or dust
removal system (distinguished from air cleaners which utilize disposable filters to
remove the dust).
Particulate scrubbers: Wet scrubber is a form of pollution control
technology. The term describes a variety of devices that use pollutants from
furnace flue gas or from other gas streams. In a wet scrubber, the polluted gas
stream is brought into contact with the scrubbing liquid, by spraying it with the
liquid, by forcing it through a pool of liquid, or by some other contact method, so
as to remove the pollutants.
Conclusion
Air pollution can be prevented only if individuals and businesses stop
using
toxic substances that cause air pollution in the first place. This would require
the
cessation of all fossil fuel-burning processes, from industrial manufacturing
home use of air conditioners. This is an unlikely scenario at this time. However,
we have to make rules which set stringent regulations on industrial and power
supply manufacturing and handling. The regulations are to be designed to
further
reduce harmful emissions into the Earth's atmosphere.
Reference
The above contents are referred from the websites
www.unacademy.com, www.researchgate.com , www.embibe.com , vedantu ,
byju’s and www.careerpowers.com and submitted to the examiner.