Atmosphere Project.pdf

The
Atmosphere.
PRESENTED BY: AIDEN, ANNOLLEE, & ZYARIE

Syllabus Objectives
9.1
9.2
9.3
explain how the concentration of ozone in the atmosphere is maintained;
discuss the environmental significance of CFCs in the ozone layer;
9.4
9.5
9.6
discuss the effects of ozone on human life;
explain the importance of maintaining the balance of carbon dioxide
concentration in the atmosphere;
discuss the effects of the products of combustion of hydrocarbon-based fuels;
explain the following terms: green-house effect, global warming, photochemical smog;

Syllabus Objectives
9.7
9.8
explain how the atmospheric concentrations of the oxides of
nitrogen may be altered;
discuss methods of control and prevention of atmospheric
pollution.

THE ATMOSPHERE IS KNOWN AS THE LAYER OF GASES THAT SURROUND A PLANET.
THIS BLANKET OF AIR SURROUNDING EARTH MAKES IT HABITABLE FOR LIFE;
WITHOUT IT, EXISTENCE WOULD NOT BE POSSIBLE AS IT PROTECTS US FROM THE
SUN'S INTENSE HEAT AND RETAINS OXYGEN FOR BREATHING.
ACCORDING TO EDUCATION SITE, VISION LEARNING EARTH'S ATMOSPHERE IS
COMPOSED OF APPROXIMATELY 78 % NITROGEN, 21 % OXYGEN, 0.93 % ARGON,
0.04 % CARBON DIOXIDE AS WELL AS TRACE AMOUNTS OF NEON, HELIUM,
METHANE, KRYPTON, OZONE, AND HYDROGEN, AS WELL AS WATER VAPOR.
What is the Atmosphere?

THE SECOND LAYER OF THE ATMOSPHERE IS REFERRED TO AS THE STRATOSPHERE.
THIS IS WHERE OZONE CAN BE FOUND. OZONE, O3, IS AN ALLOTROPIC FORM OF
OXYGEN THAT ABSORBS HARMFUL UV RADIATION FROM THE SUN.
Ozone

OZONE IS FORMED NATURALLY IN THE
STRATOSPHERE IN A REACTION CALLED
PHOTODISSOCIATION. IN THIS REACTION, LIGHT (UV)
CAUSES BOND BREAKING LEADING TO THE
DISSOCIATION OF NATURAL OXYGEN MOLECULES
INTO FREE RADICLES, WHICH ARE KNOWN TO BE
VERY REACTIVE.
AN OXYGEN MOLECULE CAN REACT WITH A RADICLE
TO FORM OZONE:
Formation of Ozone

IN RETROSPECT, OZONE CAN ALSO BE BROKEN
DOWN BY UV LIGHT TO REFORM OXYGEN AND
OXYGEN FREE RADICLES.
IN ESSENCE, THIS SYSTEM OF REACTIONS ASIDE
FROM ANY OTHER FACTORS MAINTAINS ITSELF AS
THE RATE OF FORMATION AND BREAKDOWN ARE
BALANCED, THEREFORE OZONE THEORETICALLY
REMAINS IN A CONSTANT CONCENTRATION.
THE OZONE LAYER CAN BE VIEWED AS A LAYER IN
THE STRATOSPHERE CONTAINING HIGH
CONCENTRATIONS OF OZONE WHICH PROTECT US
FROM RADIATION AND IMMENSE HEAT FROM THE SUN
Formation of Ozone cont'd

CHLOROFLUOROCARBONS (CCL2F2) UNDER NORMAL CONDITIONS ARE NON-TOXIC AND UNREACTIVE.
THESE CAN BE SEEN USED IN AEROSOLS, REFRIGERANTS, SOLVENTS, AND PACKAGING MATERIALS.
THE DOWNFALL OF CFCS ARE THAT THEY REMAIN IN OUR ATMOSPHERE FOR HUNDREDS OF YEARS AFTER
INITIAL USE. WHEN THESE MOLECULES MAKE IT TO THE STRATOSPHERE AND ARE SUBJECTED TO UV LIGHT,
THEY UNDERGO HOMOLYTIC FISSION WHICH FORMS HIGHLY REACTIVE FREE RADICLES WHICH
BREAKDOWN OZONE.
Chlorofluorocarbons

ONE CHLORINE RADICLE MAY BREAK DOWN ABOUT 100,000 OZONE MOLECULES BEFORE IT REACHES THE
STAGE OF TERMINATION. THEREFORE CFCS PRESENT IN OUR ATMOSPHERE LEAD TO OZONE DEPLETION. IF
THE OZONE LAYER IS DEPLETED WE LOSE OUR PROTECTION FROM HARMFUL RADIATION AND HEAT.
CFC's cont'd

Hole in the Ozone Layer??!
There is a region over
Antartica in which the ozone
levels are severely depleted
and this is referred to as the
ozone 'hole'.
Good news though! Ozone
levels have been slowly
recovering after the adoption
of the Montreal Protocol back
in 1987.

Montreal Protocol
The Montreal Protocol on Substances
that Deplete the Ozone Layer is the
landmark multilateral environmental
agreement that regulates the
production and consumption of nearly
100 man-made chemicals referred to
as ozone depleting substances (ODS).

Effects of Ozone Depletion on Humans
Increased ageing of the skin
Increased risk of cataracts of the eye
Increased risk of skin cancer and sunburn
Reduced resistance to certain diseases
1.
2.
3.
4.

Effects of Ozone on Human Life

Stratospheric ozone is imperative to protect
humans from the harmful UV radiation
emitted by the sun. However, ozone in the
troposphere (the closest layer of the
atmosphere to earth) can be detrimental to
humans, plants, and animals.

IRRITATING THE RESPIRATORY SYSTEM, BEING LINKED TO INCREASED ASTHMA AND BRONCHITIS
CHEST PAIN ASSOCIATED WITH COUGHING AND EMPHYSEMA
AFFECTS BLOOD VESSELS AND THE HEART. IT CAN CAUSE CHOLESTEROL-LIKE COMPOUNDS TO
FORM IN THE LUNGS LEADING TO ATHEROSCLEROSIS (HARDENING OF ARTERIES)
OZONE IS ONE OF THE PRODUCTS OF THE PHOTOCHEMICAL DECOMPOSITION OF OXIDES OF
NITROGEN, AND IS A MAJOR CONTRIBUTOR TO PHOTOCHEMICAL SMOG. WHEN NITROGEN DIOXIDE
PRODUCED BY CAR EXHAUST IS EXPOSED TO UV LIGHT IT UNDERGOES PHOTOLYTIC REACTIONS.
OZONE IN THE TROPOSPHERE AFFECTS HUMANS BY:

Carbon dioxide plays a key role in the Earth's carbon cycle. The carbon
cycle is the series of processes by which carbon compounds are
interconverted in the environment, involving the incorporation of carbon
dioxide into living tissue by photosynthesis and its return to the
atmosphere through respiration, the decay of dead organisms, and the
burning of fossil fuels.
The carbon cycle is therefore essential to the maintenance of of CO2 in
the atmosphere, however, even with the 'recycling' of carbon within the
cycle, the concentration of carbon dioxide in the earth' atmosphere has
been on the rise.
The Importance of Maintaining a
Balance of CO2 in the Atmosphere

The carbon cycle is nature's way of reusing
carbon atoms, which travel from the atmosphere
into organisms in the Earth and then back into
the atmosphere over and over again. Most
carbon is stored in rocks and sediments, while
the rest is stored in the ocean, atmosphere, and
living organisms. The ocean is a giant carbon
sink that absorbs carbon. Marine organisms like
marsh plants, fish, seaweed and birds also
produce carbon through living and dying.
Over millions of years, dead organisms can
become fossil fuels. When humans burn these
fuels for energy, vast amounts of carbon dioxide
are released back into the atmosphere. This
excess carbon dioxide changes our climate —
increasing global temperatures, causing ocean
acidification, and disrupting the planet’s
ecosystems.
The Carbon Cycle

According to NASA, humans have
increased the abundance of carbon
dioxide in the earth's atmosphere by
45% (concentration increased from
280 ppm to 412 ppm) since the
industrial revolution, leading to an
increased greenhouse effect which in
turn lead to an increase in the average
global temperature (global warming)
The Importance of Maintaining a
Balance of CO2 in the Atmosphere

1) Death of Plants and Animals
2) Weathering
3) Methane (from cow flatulence)
4) Aerobic Respiration
5) Deforestation (Burning of forests)
6) Combustion of fossil fuels in cars,
trucks, planes
7) Combustion of fossil fuels such as
coal, oil and natural gas to produce
heat and energy
CO2 Equilibrium
Sources
Sinks
1) Forests (Photosynthesis)
2) The Ocean (absorbs atmospheric
CO2 for biological process of aquatic
life)
3) The soil

Deforestation is the purposeful
clearing of forested land, and as we
progress as a global society, forests
have been razed to make space for
agriculture and infrastructure. Forests
are also cleared to obtain wood for
manufacturing and construction,
however, deforestation not only
directly reduces the amount of carbon
dioxide being absorbed from the
atmosphere by reducing the number
of the #1 carbon absorbers, trees, but
it also emits additional CO2 when the
forests are burned.
Deforestation & Reforestation
In order to combat the effects of
global warming, many reforestation
and forest preservation efforts have
been started around the globe.
Forests are responsible for moving
30% of all CO2 emissions from fossil
fuels through photosynthesis, making
them essential to maintenance of
global CO2 concentrations and
reducing the effects of global
warming.

The effect of the earth’s atmosphere in
trapping long-wave electromagnetic
radiation (Heat) and heating the earth
to a higher a temperature than it
would be without its atmosphere. In
other words, Greenhouse gases
repeatedly absorb and re-radiate
infrared radiation (heat). Energy
radiated from Earth's surface as heat,
or infrared radiation, is absorbed and
re-radiated by greenhouse gases,
impeding the loss of heat from our
atmosphere to space.
The Greenhouse Effect

Global Warming by definition is the
long-term heating of earth’s climate as
indicated by the rise in average global
temperatures.
When the concentration of greenhouse
gases increases, the atmosphere traps
and re-radiations heat for longer than
it should, increasing the average global
temperature, and drastically changing
environmental conditions
Global Warming

Photochemical smog is a mixture of
pollutants that are formed when
nitrogen oxides and volatile organic
compounds (VOCs) react to sunlight,
creating a brown haze above cities. It
is detrimental to human health, and is
responsible for various respiratory
disorders.
Global warming contributes to the
formation of photochemical fog by
increasing the amount of solar
radiation in the Troposphere,
supplying extra energy for the
formation of photochemical smog.
Photochemical Smog

The combustion of hydrocarbon fuels releases carbon dioxide (CO2), as well as other
greenhouse gases that contribute to atmospheric pollution and climate change.
Sometimes unburned hydrocarbons are released into the air during incomplete combustion.
Burning fossil fuels, including gasoline in automobile engines, releases some hydrocarbons
into the air. In a typical urban environment, the atmospheric concentration of hydrocarbons
is around 3 ppm (parts per million). Note that hydrocarbons contribute to photochemical fog.
The combustion of hydrocarbons can also release carbon monoxide if incomplete combustion
occurs and CO is poisonous to humans.
Combustion of Hydro-Carbon Based Fuels

It also releases, Sulfur dioxide. SO2, is a
colorless gas or liquid with a strong,
choking odor. It is produced from the
burning of fossil fuels (coal and oil) and the
smelting of mineral ores (aluminum, copper,
zinc, lead, and iron) that contain sulfur.
Sulfur dioxide dissolves easily in water to
form sulfuric acid. At high concentrations,
gaseous SO2 and other sulfur oxides can
harm trees and plants by damaging foliage
and decreasing growth. SO2 and other
sulfur oxides can also contribute to acid rain
which can harm sensitive ecosystems.

The world started adding lead to gasoline in the
1920s. The reason was that it is an 'antiknock
agent' which improved the efficiency of vehicles
and the performance of the engine. It turned
clunky engines into smoothly running engines.
Upon combustion, the lead atom forms lead oxide
(PbO), which prevents fractions of the fuel mixture
from burning too quickly and causing a highly
undesirable “engine knock.” But lead proved to be
a toxic pollutant – particularly for children. lead
can adversely affect the nervous system, kidney
function, immune system, reproductive and
developmental systems and the cardiovascular
system

The Nitrogen cycle is the process through which the atmospheric concentrations of the
oxides of nitrogen may be altered. The stages of the cycle are as follows:
The Nitrogen Cycle

Atmospheric fixation: The energy from lightning is used to break the triple bond between
the two nitrogen atoms (N2) so that it can then react with oxygen in the air to produce
nitrogen oxides. These nitrogen oxides are dissolved in rain forming dilute acids which are
distributed into the earth by precipitation. Atmospheric nitrogen contributes about 5-8% of
the total nitrogen fixed.
2. Industrial fixation: Under great pressure, a temperature of 600°C and the use of a
catalyst, atmospheric nitrogen and hydrogen combine to form ammonia (NH3). Ammonia
can be used as a fertilizer but most if it is further processed to urea and ammonium nitrate
(NH4NO3).
3. Biological fixation: Nitrogen being a gas cannot be used directly by plants and animals.
Rhizobium and cyanobacteria (blue-green algae) which are nitrogen fixing bacteria, and
present in the roots of plants and in water respectively contain enzymes that transform the
unstable form of nitrogen into a more readily usable form as ammonia (NH3) or nitrates
(NO3).
The Nitrogen Cycle

Assimilation
Nitrates are absorbed by plants through the roots which are then reduced to ammonium ions.
These ammonium ions are then used to make amino acids and further into proteins which
plants and animals can absorb.
Ammonification
Nitrogenous waste from plants and animals or the remains of dead organisms are converted
into ammonium (NH4) by decomposers such as bacteria and fungi.
Nitrification
• Ammonium is converted into nitrites (NO2) by the nitrifying bacteria called nitrosomonas and
the nitrobacter bacteria oxidizes nitrites into nitrates (NO3).
Denitrification
• Denitrifying bacteria reduces nitrate ions from the soil to form several intermediates which
can be released into the atmosphere including nitrous oxide (N2O), nitric oxide (NO) and
nitrogen gas (N2).
The Nitrogen Cycle

Acid decomposition, often known as acid rain, is any type of precipitation that contains
acidic components, such as sulfuric or nitric acid, which falls to the ground from the
atmosphere in wet or dry forms. This can apply to rain, snow, fog, hail, and even acidic
dust. When sulfur dioxide (SO2) and nitrogen oxides (NOx) are released into the
atmosphere and carried by wind and air currents, acid rain is the result. Nitric and sulfuric
acids are created when the SO2 and NOx react with water, oxygen, and other
substances. Then, before hitting the ground, they combine with water and other
substances. Acid rain has a pH between 4.2 and 4.4. The majority of the SO2 and NOx
that contribute to acid rain originates from burning fossil fuels, however a tiny amount
comes from natural sources like volcanoes.
Acid Rain

The main sources of SO2 and NOx in the atmosphere:
1. Power plants
2. Burning of fossil fuels (gasoline) to produce electricity. Electric power generators are
responsible for 2/3 of the SO2 and ¼ of the NOx in the environment.
3. Automobiles and large machinery.
4. Industries such as petroleum refineries, cement manufacturing, metal smelting etc.
SOURCES ON SO2 AND NOx

SCRUBBERS
• Scrubbers are a type of pollution control device that eliminates air pollutants from industrial
emissions, including sulfur dioxide, chlorine, hydrogen sulfide, and hydrogen chloride. The two main
types are wet and dry scrubbers.
• Wet scrubbers use liquids to absorb gases or particles from a steam of air. A spray tower is a
typical low-energy wet scrubber that disperses liquid by sending exhaust through an open vessel
equipped with sprayers. The liquid either absorbs the target gas or takes up floating particles as the
exhaust passes through the device. Similar to wet scrubbers, dry scrubbers spray dry chemicals into
the flue stream in order to neutralize gases before they reach the atmosphere.
• Scrubbers are a very useful technology for pollution management because they keep populations
near industrial hubs like power plants and water treatment facilities from being harmed by harmful
air pollutants. Furthermore, because these devices don't interfere with production, commercial and
industrial activity can continue without an increase in air pollution.
METHODS FOR CONTROLLING
ATMOSPHERIC POLLUTION

FILTERING
• In the relatively newer air pollution control (APC) method known as biofiltration, off-gases
containing biodegradable volatile organic compounds (VOC) or inorganic air toxins are vented
through a biologically active substance.
• Biofilters function by absorbing harmful gases into a biofilm, where microorganisms convert the
pollutants into carbon dioxide, water, and salts and use the energy and nutrients for growth and
reproduction. Hydrogen sulfide (H2S), ammonia (NH3) and odors can all be reduced by up to 95%
and 80%, respectively, with properly constructed and managed biofilters.

SEQUESTERING
• Carbon sequestration is the act of removing carbon dioxide from the atmosphere and burying it
deeply within the earth to prevent it from ever polluting the planet. Carbon sequestration attempts
to take carbon dioxide from the atmosphere and store it in a location where it cannot further
contribute to climate change. The two types are geologic and biologic carbon sequestration.
- Geologic carbon sequestration: storing carbon dioxide using geologic formations, which entails
putting the gas under pressure until it becomes liquid and injecting it into rocks in that liquid state.
- Biologic carbon sequestration: is the process of storing captured carbon dioxide in
various biological reservoirs: such as vegetation, soil, and aquatic environments

WASHERS
• Air washer systems are a simple but effective way of creating an ideal indoor climate when the air
is dry and polluted.
How do air washers work?
1. Ventilation air comes into contact with water.
2. The water inside the air washer is continuously pumped around, together with the ventilation air.
3. The washing water absorbs dust, odor and ammonia particles from the ventilation air.
4. Clean outgoing air leaves the washer.

• Any materials or substances that can be used as fuels but are not classified as conventional fuels,
also known as non-conventional and advanced fuels.
• Alternative fuels include gaseous fuels like hydrogen, natural gas, and propane; alcohols like
ethanol, methanol, and butanol; and liquid fuels such as higher-level ethanol blends, biodiesel, and
renewable diesel. Employing an alternate fuel can help to lower carbon emissions.
Why use alternative fuels?
- Alternative fuel vehicles (AFVs) emit fewer hazardous pollutants and have lower emissions when
compared to gasoline and diesel vehicles. Additionally, AFVs inherently emit fewer harmful
pollutants, including toxic contaminants compared to diesel and gasoline vehicles. Evaporative and
start emissions are especially dramatically decreased.
ALTERNATIVE FUELS

- Clean Fuels are fuels that have had their greenhouse gas emissions reduced by ethanol
treatment. These fuels are low pollution fuels such as renewable natural gas, liquified
petroleum gas (LPG), biogas and electricity generated from sustainable and renewable
resources rather than fossil fuels.
Why use clean fuels?
- Clean fuels will reduce greenhouse gas emissions from transportation fuels, improve air
quality, and make low-carbon fuels more affordable and available.
CLEAN FUELS

Why use mass transit?
- Less pollution and clearer skies: Using public transit instead of driving alone cuts CO2
emissions by 45%, lowering air pollution and increasing air quality.
- Healthier communities: More health advantages for local residents result from improved air
quality. This may result in fewer incidences of cancer and respiratory illnesses like asthma.
- Harmful chemicals are reduced: When it comes to cars, we typically only consider gas as a
pollution, but they also consume antifreeze and other harmful substances. All of them are
reduced when using sustainable transportation instead of a car.
MASS TRANSIT/PUBLIC TRANSPORTATION

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