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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
一类物质的总称一类物质的总称 经化学反应或光化学反应形成经化学反应或光化学反应形成 反应生成物与反应物的物理、化反应生成物与反应物的物理、化
学性质完全不同学性质完全不同 它是在大气中由一次污染物反应它是在大气中由一次污染物反应
得来得来
二次污染物二次污染物
Heat island effect ( 热岛效应 ) Temperature difference between a city and its countryside can be as high as 4 – 6 oC.
Factor for air pollution
Heat island effect
33°
29°
te
mp
era
ture
(°C
)
Rural Suburbanresidential
Commercial Downtown Urbanresidential
Park Suburbanresidential
Ruralfarmland
Why heat island effect?
Cities absorb much more heat than rural areas.
Urban: paved streets and buildingsRural: vegetation and soil
How to reduce heat island effect?
• Reduce the area of land with high heat capacity 减少大热容量的地面面积
• Roofs: put more vegetation; change to leisure place 楼顶绿化或建成休息场所
• Tear down walls, modify building direction, improve aeration 拆去围墙改变楼群方向,改善通风效果
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
Major contents of the course
Major types of Air Pollution
伦敦烟雾 London Smog
光化学烟雾 Photochemical Smog
温室效应 Greenhouse Effect
酸 雨 Acid Rain
臭氧层破坏 Ozone Depletion
Major types of Air Pollution
伦敦烟雾 London Smog
光化学烟雾 Photochemical Smog
温室效应 Greenhouse Effect
酸 雨 Acid Rain
臭氧层破坏 Ozone Depletion
Greenhouse effect A natural effect that releases heat in the
lower part of atmosphere (troposphere) near the earth’s surface.
Greenhouse gases absorb some of the infrared radiation (heat) emitted by the earth’s surface.
Natural Greenhouse effect
If greenhouse
gases were not
present, the mean
temperature of the
earth's surface
would be ~ 33oC
colder.
What are the major greenhouse
gases?Natural source: H2Ov – water vapor
CO2 – carbon dioxide
CH4 – methane
N2O – nitrous oxide
O3 – ozone
Canada
China
Russia
Japan
India
Germany
United Kingdom
United States
Italy
France
25.5%
11.2%
6.7%
5.1%
4.1%
3.9%
2.6%
2.5%
2.0%
1.8%
Contribution to Global Total (%)
Russia
Canada
Australia
Netherlands
Belgium
Germany
Czech Republic
United States
United Kingdom
France
5.6%
4.9%
4.9%
4.1%
3.7%
2.8%
2.8%
2.7%
2.6%
1.8%
Per Capita Emissions (metric tons)
Average temperature over past 130 years
Year
Ave
rag
e su
rfac
e te
mp
erat
ure
(°C
)
1860 1880 1900 1920 1940 1960 1980 2000 2020
13.6
13.8
14.0
14.2
14.4
14.6
14.8
15.0
Global warming
Today’s sea level
Years before present Present
250,000 200,000 150,000 100,000 50,000 0
–130
0
–426
0
Hei
gh
t ab
ove
or
bel
ow
pre
sen
t se
a le
vel
(met
ers)
Hei
gh
t ab
ove
or
bel
ow
p
rese
nt
sea
leve
l (f
eet)
Rise of sea level
Kyoto Protocol ( 京都议定书 )
At the Intergovernmental Panel on Climate
Change (IPCC, 政府间气候变化专门委员会 )
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%
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
Major types of Air Pollution
伦敦烟雾 London Smog
光化学烟雾 Photochemical Smog
温室效应 Greenhouse Effect
酸 雨 Acid Rain
臭氧层破坏 Ozone Depletion
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.
Statue carved in 1702 photographed in 1908 (left) and 1969 (right).
CaCO3 + H2SO4 CaSO4 + 2H+ + CO32-
The calcium sulfate is soluble so it is easily washed away during the next rain storm.
Damages buildings and monuments
Harms forests
Emission
Aciddeposition
Direct damageto leaves
Reducedphotosynthesis
and growth
Soil acidification
Harms forests
Emission
Aciddeposition
Direct damageto leaves
Reducedphotosynthesis
and growth
Release oftoxic
metalsAcid
Leaching ofsoil
nutrients
Soil acidification
Harms forests
Emission
Aciddeposition
Direct damageto leaves
Reducedphotosynthesis
and growth
Reducednutrient
andwater
uptake
Rootdamage
Release oftoxic
metalsAcid
Leaching ofsoil
nutrients
Soil acidification
Harms forests
Emission
Aciddeposition
Direct damageto leaves
Reducedphotosynthesis
and growth
Increasedsusceptibility
to stress
Reducednutrient
andwater
uptake
Rootdamage
Release oftoxic
metalsAcid
Leaching ofsoil
nutrients
Soil acidification
Harms forests
Emission
Aciddeposition
Direct damageto leaves
Reducedphotosynthesis
and growth
Increasedsusceptibility
to stress
Tree death
Reducednutrient
andwater
uptake
Rootdamage
Release oftoxic
metalsAcid
Leaching ofsoil
nutrients
Soil acidification
What is this substance?
A greenhouse gas
A secondary pollutant
Regulates UV level
Ozone
Can warm up atmosphere
Major types of Air Pollution
伦敦烟雾 London Smog
光化学烟雾 Photochemical Smog
温室效应 Greenhouse Effect
酸 雨 Acid Rain
臭氧层破坏 Ozone Depletion
What is ozone?Ozone is a stable molecule composed of three oxygen atoms, and has a strong pungent odor.
O
O
O
Ozone depletion: when sum of ozone over height is lower than 2/3 of the normal value, "ozone depletion" occurs.
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
P. Crutzen, M. Molina and S. Rowland
received Nobel Prize in Chemistry in 1995
for their contribution in ozone depletion
research.
August 7, 2001
October 10, 2001
35
30
25
20
15
10
5
0 5 10 15Ozone partial pressure (milipascals)
Alt
itu
de (
kilom
ete
rs)
Questions
• Why ozone depletion occurs mostly in two poles?
• Why ozone layer thinning in Antarctica is seasonal?
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.
Solutions to ozone depletion
• Immediately stop producing all ozone-depleting chemicals.
• Find substitutes ( 替代物 ) for CFCs, such as propane ( 丙烷 ) and butane ( 丁烷 ), which are less costly.
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.
Year
1950 1975 2000 2025 2050 2075 2100
3,000
0
6,000
9,000
12,000
15,000
Ab
un
da
nc
e (p
art
s p
er
trill
ion
)
No protocol
1987MontrealProtocol
1992CopenhagenProtocol