Environmental Science

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Environmental Science
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What is this matter?

• be more important than our daily bread

be needed for the metabolic processes within the
cells
made up a part of the atmosphere
Air
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• ?????????

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???????75
???????
???(Troposphere)
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What is this phenomenon?

• ????????????

CO,NOx and CxHy
NO?NO2??
????????????
Photochemical smog
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?????????

• ?????????????

????????
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?????????????
????(sulfur dioxide)
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• ????

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• ?????????????????????
• ????????????????
• ?????

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• ????????
• ??????????,????????????
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Factor for air pollution

• Heat island effect (????) Temperature
  difference between a city and its countryside can
  be as high as 4 6 oC.

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Heat island effect
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temperature (C)
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Rural
Suburban residential
Commercial
Downtown
Urban residential
Park
Suburban residential
Rural farmland
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Why heat island effect?

Urban paved streets and buildings Rural
vegetation and soil
Cities absorb much more heat than rural areas.
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Air above city more pollutants, more greenhouse
gases
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Heat island effect
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How to reduce heat island effect?

• Reduce the area of land with high heat capacity
  ???????????
• Roofs put more vegetation change to leisure
  place ???????????
• Tear down walls, modify building direction,
  improve aeration ??????????,??????

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Environmental Science ???(??)

• Prof. Ge Ying
• Nanjing Agricultural University

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Major contents of the course
Chapter 1 Introduction Chapter 2 Population
and environment Chapter 3 Energy and
environment Chapter 4 Air pollution and its
control Chapter 5 Sustainable development
Chapter 6 Water pollution and its
control Chapter 7 Soil pollution and its
control Chapter 8 Noise and solid waste
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Major types of Air Pollution
???? London Smog ????? Photochemical Smog
???? Greenhouse Effect ? ? Acid Rain ?????
Ozone Depletion
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Major types of Air Pollution
???? London Smog ????? Photochemical Smog
???? Greenhouse Effect ? ? Acid Rain ?????
Ozone Depletion
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Greenhouse effect

• A natural effect that releases heat in the lower
  part of atmosphere (troposphere) near the earths
  surface.
• Greenhouse gases absorb some of the infrared
  radiation (heat) emitted by the earths surface.

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Natural Greenhouse effect
If greenhouse gases were not present, the mean
temperature of the earth's surface would be
33oC colder.
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Animation Greenhouse effect and global warming
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What are the major greenhouse gases?

• Natural source
• H2Ov water vapor
• CO2 carbon dioxide
• CH4 methane
• N2O nitrous oxide
• O3 ozone

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What are the major greenhouse gases?

• Human source
• CFCs chlorofluorocarbons

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410
360
Parts per million
310
260
1800
1900
2000
2100
Year
Carbon dioxide (CO2)
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2.4
1.8
Parts per million
1.2
0.6
1800
1900
2000
2100
Year
Methane (CH4)
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320
310
Parts per million
300
290
260
1800
1900
2000
2100
Year
Nitrous oxide (N2O)
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????,?????????
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Contribution to Global Total ()
25.5
11.2
6.7
5.1
4.1
3.9
2.6
2.5
2.0
1.8
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Per Capita Emissions (metric tons)
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Global warming
Average temperature over past 130 years
15.0
14.8
14.6
14.4
Average surface temperature (C)
14.2
14.0
13.8
13.6
1860
1880
1900
1920
1940
1960
1980
2000
2020
Year
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The Day after Tomorrow
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Rise of sea level
Todays sea level
0
0
Height above or below present sea level (feet)
Height above or below present sea level (meters)
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426
250,000
200,000
150,000
100,000
50,000
0
Years before present
Present
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Major urban region at risk
Islands at risk
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Kyoto Protocol (?????)

• At the Intergovernmental Panel on Climate
  Change (IPCC, ????????????) meeting in Kyoto,
  Japan, in December 1997, 160 nations agreed on a
  landmark treaty.
• Developed countries cut 5.2 on the 1990
  level, US 7 EU 8 Japan 6

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How to slow down global warming?

• Cut fossil fuel use (especially coal)
• Improve energy efficiency
• Shift from coal to natural gas
• Shift to renewable energy resources
• Transfer energy efficiency and renewable energy
  technologies to developing countries
• Reduce deforestation
• Slow population growth

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Major types of Air Pollution
???? London Smog ????? Photochemical Smog
???? Greenhouse Effect ? ? Acid Rain ?????
Ozone Depletion
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What is Acid Rain?
Acid rain is rain which has a pH of 5.6 or below
when water in clouds chemically reacts with
natural CO2 or pollutants.
NATURAL Causes Carbon Dioxide (CO2) in the
atmosphere. HUMAN Causes Emissions of Sulphur
Dioxide (SO2) and Nitrogen Oxides (NOx) from
cars and factories.
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• Damages lakes and streams
• Deadly to aquatic wildlife

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Damages buildings and monuments
Statue carved in 1702 photographed in 1908 (left)
and 1969 (right).
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Harms forests
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Harms forests
Emission
Acid deposition
Direct damage to leaves
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Harms forests
Emission
Acid deposition
Reduced photosynthesis and growth
Direct damage to leaves
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Harms forests
Emission
Acid deposition
Reduced photosynthesis and growth
Direct damage to leaves
Soil acidification
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Harms forests
Emission
Acid deposition
Reduced photosynthesis and growth
Direct damage to leaves
Soil acidification
Release of toxic metals
Leaching of soil nutrients
Acid
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Harms forests
Emission
Acid deposition
Reduced photosynthesis and growth
Direct damage to leaves
Soil acidification
Reduced nutrient and water uptake
Release of toxic metals
Leaching of soil nutrients
Root damage
Acid
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Harms forests
Emission
Acid deposition
Increased susceptibility to stress
Reduced photosynthesis and growth
Direct damage to leaves
Soil acidification
Reduced nutrient and water uptake
Release of toxic metals
Leaching of soil nutrients
Root damage
Acid
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Harms forests
Emission
Acid deposition
Increased susceptibility to stress
Reduced photosynthesis and growth
Direct damage to leaves
Soil acidification
Tree death
Reduced nutrient and water uptake
Release of toxic metals
Leaching of soil nutrients
Root damage
Acid
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Soil acidification
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• Soil sampling around Taihu Lake

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Soil pH variation
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Lucky 100'

• Environmental Science

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What is this substance?

• A greenhouse gas

Can warm up atmosphere
A secondary pollutant
Regulates UV level
Ozone
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Major types of Air Pollution
???? London Smog ????? Photochemical Smog
???? Greenhouse Effect ? ? Acid Rain ?????
Ozone Depletion
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What is ozone?

• Ozone is a stable molecule composed of three
  oxygen atoms, and has a strong pungent odor.

Ozone depletion when sum of ozone over height is
lower than 2/3 of the normal value, "ozone
depletion" occurs.
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CFCs

• Dream chemical
• Chemically stable, nonflammable, nontoxic,
  noncorrosive, odorless
• Widely used for coolants, cleaners, bubbles, etc.
• Nightmare chemical
• Destroy ozone layer due to its Cl atom

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Animation Major reactions involved in the ozone
depletion
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• P. Crutzen, M. Molina and S. Rowland received
  Nobel Prize in Chemistry in 1995 for their
  contribution in ozone depletion research.

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ozone hole
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August 7, 2001
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October 10, 2001
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Altitude (kilometers)
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10
5
0
5
10
15
Ozone partial pressure (milipascals)
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Questions

• Why ozone depletion occurs mostly in two poles?
• Why ozone layer thinning in Antarctica is
  seasonal?

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Why should we worry?

• A 1 decrease in ozone results in a 1.3 to 2
  increase in the UV-B levels at the surface of the
  earth.
• Human health damage sunburn, skin cancers,
  immune system suppression, etc.

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Solutions to ozone depletion

• Immediately stop producing all ozone-depleting
  chemicals.
• Find substitutes (???) for CFCs, such as propane
  (??) and butane (??), which are less costly.

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What has been done?

• Montreal Protocol (1987) cut emission of CFCs
  into the atmosphere by about 35 between 1989 to
  2000.
• Copenhagen Protocol (1992) phase out key
  ozone-depleting chemicals.

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15,000
No protocol
12,000
1987 Montreal Protocol
9,000
Abundance (parts per trillion)
6,000
1992 Copenhagen Protocol
3,000
0
1950
1975
2000
2025
2050
2075
2100
Year
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Summary

• Greenhouse effect pollutants, consequence,
  solutions
• Acid rain pollutants, reactions, damages,
  solutions
• Ozone depletion ozone, CFCs, reactions, damages,
  solutions