Top 2 Earth Structure

7/31/2019 Top 2 Earth Structure

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ICHEM 115 Environmental Chemistry

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CHAPTER 2

EARTH STRUCTURE


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EarthStructure

Source: http://library.thinkquest.org


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Structure of Earth

Zone Main constituents Condition

Atmosphere N2, O2, H2O, particles,

particulates

Gas, liquid, solid

Hydrosphere H2O Liquid

Biosphere H2O, Organic material Solid, liquid,

gas, colloidal

Crust Silicate rocks, oxide, sulfite

minerals

Solid (with water

and air)

Mantle Silicate materials, Fe & Mg

silicates

Solid

Core Fe-Ni alloy Liquid

Solid


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Core

The inner most part of the earth.

Divided into inner core and outer core.

Inner core: solid

Outer core: semi-solid


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Mantle

1. Upper/ Outer mantle

Lithosphere, Asthenosphere, solid

igneous rock, transition zone, spinel

structure, second transition zone

2. Lower mantle

3. 82% of the Earths volume.


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Crust

Continental crust - complex structure and

composition

Oceanic crust (10km)- surface sediment

covering basaltic rocks.


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Hydrosphere

It includes oceans, seas, rivers, streams, lakes,

swamps, groundwater and atmospheric water.

Oceans are important in as they modify climate by

- absorbing solar radiation and transport the heat

- controlling abundances of oxygen and carbon

dioxide which are necessary for life processes- water evaporating from oceans, falls as rain/snow

on land (hydrological cycle).


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Atmosphere

It refers to the envelope of gases around theworld.

Nitrogen: 78%

Oxygen: 21%

Carbon dioxide: 0.03%

Argon: 0.93%

Others: 0.01%


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Atmospheric Layers

Troposphere: sea level to 17km

Stratosphere: 17km 48km

Mesosphere: 49km 80kmThermosphere: above 80km


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Atmospheric layers

Source: http://wings.avkids.com/Book/Atmosphere/Images/atmos_layers.gif


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Structure of Atmosphere


Source of diagram:http://burro.cwru.edu/Academics/Astr201/Atmosphere/atmosphere1.html

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Pollutants

A pollutant is defined as a substance that is

potentially harmful to the health and well-

being ofhuman, animal, plant, and may

affect the aesthetic value of the surrounding.


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Air Pollutants

Air pollutants can be in the form of gas or

particulates.

Particulate matter

The size ranges from 0.01 micron to >100

micron.

Important size: PM10 and PM2.5


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Source: http://www.solarfasttrack.com/latest/air_pollution_facts.htm 15


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Air Pollutants (contd)

Categories based on regulation

Unregulated air pollutants:

Carbon dioxide (CO2), Nitrous oxide (N2O)

Regulated air pollutants:

Sulfur dioxide (SO2), Nitrogen oxides (NOx),carbon monoxide (CO), Ozone (O3)


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Categories based on how they are formed

Primary pollutants: emitted directly into theatmosphere.

Example: CO from incomplete fossil fuelcombustion, SO2 from power station

Secondary pollutants: formed in the air as a result

of chemical reactions with other pollutants andatmospheric gases.

Example: tropospheric ozone



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Categories based on sources

Natural sources: volcanic eruptions, storms,

lighting and forest fires

Anthropogenic sources: fossil fuel burning,

industrial process, natural gas leakage in thedistribution network.



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Application and enforcement of emission standard

Limit values are mandatory while guideline/ guide valuesare for long-term precautions.

Common emission standards that are used as guidelines:

- by European Commission (EC)

- by United Nations Economic Commision for Europe

(UNECE)- by US Environmental Protection Agency (USEPA)

Control of Air Pollutants


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Air Pollution Index (API)

API Air pollution level

0-50 Good

51-100 Lightly polluted

101-200 Polluted, unhealthy for human

201-300 Heavily polluted, very unhealthy for human

300 and above Severely polluted


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Biosphere

The zone that supports the life on the Earth.

It covers a fraction of the Earths crust, thehydrosphere and lower regions of the

atmosphere.

Includes animals, insects, reptiles, microbes,

planktons, fungi, plants, molds.


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Thank you

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Top 2 Earth Structure