environmental science

Environmental Science

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

在下列描述中说出这是什么？

温度随高度升高降低

质量占大气圈的 75%

大气圈的最底层

对流层 (Troposphere)

大气污染现象的主要发生地

CO ， NOx and CxHy

What is this phenomenon?

对眼睛和呼吸道有刺激作用

NO 向 NO2 转化

Photochemical smog

发生在以石油为燃料的地区

这是哪一种污染物？

世界范围内的主要气态污染物

对植物内部的生理活动有抑制作用

参与了硫酸烟雾和酸雨的形成

二氧化硫 (sulfur dioxide)

主要来自燃料燃烧

根据暗示联想猜词

代表爱情

原点、辐射线

气象学词汇

风向玫瑰图

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

一种气体一种气体有刺激性气味有刺激性气味在大气中易被氧化在大气中易被氧化氧化产物与水分子结合，生成物氧化产物与水分子结合，生成物

给人类带来巨大危害给人类带来巨大危害

二氧化硫二氧化硫

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

Air above city: more pollutants, more greenhouse gases

citysuburb countrysidecountryside

temp

pollutant concair flow

Heat island effect

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

Environmental Science 环境学 ( 双语 )

Prof. Ge Ying

Nanjing Agricultural University

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

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.

Animation Greenhouse

effect and global warming

What are the major greenhouse

gases?Natural source: H2Ov – water vapor

CO2 – carbon dioxide

CH4 – methane

N2O – nitrous oxide

O3 – ozone

What are the major greenhouse

gases?

Human source: CFCs – chlorofluorocarbons

Carbon dioxide (CO2)

Year1800 1900 2000 2100

260

310

360

410P

arts

per

mil

lio

n

Methane (CH4)Year

1800 1900 2000 21000.6

1.2

1.8

2.4P

arts

per

mil

lio

n

Year

Par

ts p

er m

illi

on

1800 1900 2000 2100260

290

300

310

320

Nitrous oxide (N2O)

不能打嗝，这日子可怎么过啊？

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

The Day after

Tomorrow

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

Major urban region at risk Islands at risk

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





酸雨 Acid Rain


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.

Damages lakes and streams

–Deadly to aquatic wildlife

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

Harms forests

Emission

Aciddeposition

Direct damageto leaves

Harms forests

Emission

Aciddeposition


Reducedphotosynthesis

and growth

Harms forests

Emission

Aciddeposition



and growth

Soil acidification

Harms forests

Emission

Aciddeposition



and growth

Release oftoxic

metalsAcid

Leaching ofsoil

nutrients

Soil acidification

Harms forests

Emission

Aciddeposition



and growth

Reducednutrient

andwater

uptake

Rootdamage

Release oftoxic

metalsAcid

Leaching ofsoil

nutrients

Soil acidification

Harms forests

Emission

Aciddeposition



and growth

Increasedsusceptibility

to stress

Reducednutrient

andwater

uptake

Rootdamage

Release oftoxic

metalsAcid

Leaching ofsoil

nutrients

Soil acidification

Harms forests

Emission

Aciddeposition



and growth

Increasedsusceptibility

to stress

Tree death

Reducednutrient

andwater

uptake

Rootdamage

Release oftoxic

metalsAcid

Leaching ofsoil

nutrients

Soil acidification

Soil acidification

Soil sampling around Taihu Lake

Soil pH variation

Lucky 100'

Environmental Science

What is this substance?

A greenhouse gas

A secondary pollutant

Regulates UV level

Ozone

Can warm up atmosphere





酸雨 Acid Rain


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

AnimationMajor reactions

involved in the ozone depletion

P. Crutzen, M. Molina and S. Rowland

received Nobel Prize in Chemistry in 1995

for their contribution in ozone depletion

research.

“ozone hole”

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

Summary

• Greenhouse effect: pollutants, consequence, solutions

• Acid rain: pollutants, reactions, damages, solutions

• Ozone depletion: ozone, CFCs, reactions, damages, solutions

environmental science

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