Chapter One
The Air We Breathe
What is in the air that we breathe?
Can air be dangerous to our health?
How can understanding chemistry help us decide?
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Where are we leaving ?
The Composition of Our Air in Troposphere
It’s a mixture – a physical combination of two or
more substances present in variable amounts.
1.2
Air Composition


Nitrogen; N2; 78 %; Oxygen; O2; 21 %
Argon; Ar; 0.9 %; Other Gases; 0.1 %
O2
Nitrogen
Ar
Oxygen
Argon
N2
Other
Composition of the other gasses
Gas
% volume
Argon (Ar)
0.934%
CO2
350 mmv
Ne
18.18 ppmv
He
5.24 ppmv
CH4
Kr
H2
1.7 ppmv
1.14 ppmv
0.55 ppmv
One Breath has 2.0 X 1022 molecules
20 000 000 000 000 000 000 000
How many N2 molecules
Are in a breath of air?
Ozone (O3)
If one breath of air contains 2 x 1022 molecules and atoms, and
the acceptable ozone level is 0.12 ppm, how many molecules
of O3 are in each breath?
2 x 1022 molecules and atoms in a breath of air x
0.12 O3 molecules
1 x 106 molecules
and atoms in air
= 2 x 1015 O3 molecules in a breath
How many oxygen atoms are in each breath?
2 x 1015 O3 molecules x 3 O atoms___
1 O3 molecules
= 6 x 1015 O atoms
1.12
What’s in
a Breath?
When people breathe
Typical Composition of Inhaled and Exhaled Air
Substance
Nitrogen
Oxygen
Argon
Carbon dioxide
Water
Inhaled air
(%)
78.0
21.0
0.9
0.04
Exhaled air
(%)
75.0
16.0
0.9
4.0
0.0
4.0
Concentration Terms
Parts per hundred (percent)
Atmosphere is 21% oxygen = 21 oxygen molecules
per 100 molecules of air
Parts per million (ppm)
Midday ozone levels reach about 0.4 ppm =
0.4 ozone molecules
1 x 106 molecules of air
Parts per billion (ppb)
Sulfur dioxide in the air should not exceed 30 ppb =
30 sulfur dioxide molecules
1 x 109 molecules of air
1.2
21% means 21 parts per hundred
means 210 parts per thousand
means 2,100 parts per ten thousand
means 21,000 parts per hundred thousand
The
difference
between
pph and
ppm is a
factor of
10,000
means 210,000 parts per million
Try Chapter 1 Figures Alive! for practice
1.2
Classifying Matter
All Matter
NO
Can it be separated by
a physical process?
Pure
Substances
NO
Elements
Can it be broken
down into
simpler ones by
chemical means?
YES
Mixtures
YES
Compounds
1.6
Three States of Matter
Matter - anything
that occupies space
and has mass.
1.5
Classifying Matter
Classify each of these as an element, a compound, or a mixture:
carbon dioxide compound
nickel
element
cocaine
compound
water
compound
fluorine
element
table salt
compound
soap
mixture
sea water
mixture
1.6
The Periodic Table
Group
Period
A space filling model for a
water molecule, H2O
Oxygen atom
A molecule is a combination of a
fixed number of atoms held
together in a certain spatial
arrangement.
Two hydrogen atoms
The chemical formula
symbolically represents the type
and number of each element
present.
1.7
Many nonmetals occur as diatomic
(made up of two atoms) molecules
H2
N2
O2
Cl2
1.7
Naming Binary Compounds
1. Name the more metallic element first, followed by the name of
the less metallic element, modified with the suffix “ide”
KBr postassium bromide
BeO beryllium oxide
ZnS zinc sulfide
1.8
Naming Binary Compounds
2. Prefixes are used to designate the number of each type
of element:
number of atoms
prefix
1
mono
2
di
3
tri
4
tetra
5
penta
6
hexa
7
hepta
8
octa
9
nona
10
deca
1.8
Chemical Equations



Reactant(s) -> Product(s)
Carbon + Oxygen -> Carbon Dioxide
C (s) + O2 (g) -> CO2 (g)
•Reactant bonds are broken; Product bonds are made
•Same number and type of atoms on both sides of equation
Chemical reactions are characterized by the rearrangement
of atoms when reactants are transformed into products
C + O2
CO
reactants
product
This is an example of a
combustion reaction
But the number of atoms on each side of the arrow
must be equal (Law of Conservation of Mass)
2 C + O2
2 CO
(balanced)
2 carbon atoms
two carbon atoms
2 oxygen atoms
two oxygen atoms
1.9
2C
+
O2
2 CO
+
1.9
Balancing equations:
-if an element is present in just one compound on each
side, balance it first
-balance anything that exists as a free element last
- balance polyatomic ions as a unit
- check when done – same number of atoms, and same
total charge on both sides
C3H8 + O2
C3H8 + 5 O2
3 C atoms
8 H atoms
10 O atoms
CO2 + H2O
3 CO2 + 4 H2O
3 C atoms
8 H atoms
10 O atoms
1.9
Direct Source of Sulfur Trioxide
Coal +
O2
SO2
(1-3% sulfur)
2 SO2
+
O2
2 SO3
Good News: Since 1985 we have seen a 25% reduction in SO2
emissions in the U.S.
1.11
Direct Source of Nitrogen Oxides
N2
+ O2 + high temp
NO is very reactive:
2 NO
+
O2
High temperatures
from auto engine or
2 NO
coal-fired power
(nitrogen oxide)
plant
Simplified version of
chemistry that occurs
2 NO2
1.11
Properties of the troposphere
Atmospheric pressure
changes with altitude
temperature changes
In Troposphere :
Altitude increases  P and
T decrease
In Thermosphere :
Altitude increases  P
decrease, T increases
Quality of The Air



Air Quality Index (AQI) : USA
Air Pollution Index (API) : Hong Kong, China,
Malaysia
Indeks Standar Pencamaran Udara (ISPU) :
(Air Pollution Standard Index /APSI)
Indonesia
Air Quality standards
How are standards
established?
Through risk assessment
--consider the toxicity of the
compound and the exposure.
Toxicity: How dangerous a
compound is.
Exposure: Refers to the length
of contact with the pollutant and
the concentration of the
pollutant
EPA’s Air Quality Index
Air Quality Index
(AQI) Values
Levels of Health
Concern
Colors
When the AQI
is in this range:
...air quality
conditions are:
Good
...as symbolized
by this color:
Green
Moderate
Yellow
Orange
050
51–100
101–150
151–200
201–300
301–500
Unhealthy for
sensitive groups
Unhealthy
Very unhealthy
Hazardous
Red
Purple
Maroon
1.3
Indonesian Air Quality Index
(indeks standar pencemaran
udara =ISPU)

Pollutant parameters :





Carbon monoksida (CO)
Nitrogen (NO2)
Ozone (O3)
Sulfur dioxide (SO2)
Particulate Matter (PM10)
Hubungan ISPU dan kondisi lingkungan
Kategori
Rentang
Karbon
monoksida (CO)
Nitrogen (NO2)
Ozon (O3)
Sulfur dioksida
(SO2)
Partikulat
0-50
Tidak ada efek
Sedikit berbau
Luka pada
Beberapa spesies
tumbuhan akibat
kombinasi dengan
SO2 (Selama 4
Jam)
51 - 100
Perubahan kimia
darah tapi tidak
terdeteksi
Berbau
Luka pada
Beberapa spesies
tumbuhan
Luka pada
Beberapa spesies
tumbuhan
Terjadi penurunan
pada jarak pandang
101 - 199
Peningkatan pada
kardiovaskular pada
perokok yang sakit
jantung
Bau dan kehilangan
warna. Peningkatan
reaktivitas
pembuluh
tenggorokan pada
penderita asma
Penurunan
kemampuan pada
atlit yang berlatih
keras
Bau, Meningkatnya
kerusakan tanaman
Jarak pandang turun
dan terjadi
pengotoran debu di
mana-mana
Sangat
Tidak Sehat
200-299
Meningkatnya
kardiovaskular pada
orang bukan perokok
yang berpenyakit
Jantung, dan akan
tampak beberapa
kelemahan yang terlihat
secara nyata
Meningkatnya
sensitivitas pasien
yang berpenyakit
asma dan bronchitis
Olah raga ringan
mengakibatkan
pengaruh
parnafasan pada
pasien yang
berpenyaklt paruparu kronis
Meningkatnya
sensitivitas pada
pasien berpenyakit
asma dan bronchitis
Meningkatnya
sensitivitas pada
pasien berpenyakit
asma dan bronchitis
Berbahaya
300 - lebih
Tingkat yang berbahaya bagi semua populasi yang terpapar
Baik
Sedang
Tidak Sehat
Luka pada
Beberapa spesies
tumbuhan akibat
kombinasi dengan
O3 (Selama 4 Jam)
Tidak ada efek

API- Malaysia
0-50 Good
51-100 Moderate
101-200 Unhealthy
201-300 Very unhealthy
301- Hazardous
Air Pollution


Air pollutants are airborne particles and gasses that
occur in concentrations that endanger the health and
well-being of organisms or disrupt the orderly
functioning of the environment.
Pollutants can be grouped into two categories:


(1) primary pollutants, which are emitted directly from
identifiable sources, and
(2) secondary pollutants, which are produced in the
atmosphere when certain chemical reactions take place
among primary pollutants.
Primary Pollutants
The major primary pollutants include:






particulate matter (PM),
sulfur dioxide,
nitrogen oxides,
volatile organic compounds (VOCs),
carbon monoxide, and
lead.
Secondary Pollutants





Atmospheric sulfuric acid is one example of a
secondary pollutant.
Air pollution in urban and industrial areas is often
called smog.
Photochemical smog, a noxious mixture of gases and
particles, is produced when strong sunlight triggers
photochemical reactions in the atmosphere.
The major component of photochemical smog is
ozone.
Although considerable progress has been made in
controlling air pollution, the quality of the air we
breathe remains a serious public health problem.
Major Sources of Air Pollutants

Combustion of coal in coal burning power
plants


Coal is mostly Carbon; The main impurity in coal is
sulfur, S.
Combustion of fuel in car, trucks, and other
vehicles.
Sulfur Oxides, SOx
SO2, SO3
When coal is burned, so is the Sulfur impurity
S + O2
SO2
The SO2 then burns to produce SO3.
2 SO2 + 1 O2
2 SO3
SO3 gas then dissolve in water to
make a component of acid rain,
H2SO4 (aq).
SO3 (g) + H2O (l)
H2SO4 (aq)
In general; nonmetal oxides dissolve in water to make it acidic
Problems with SOx
1.
2.
SOx are respiratory irritants
SOx dissolve in water to make a component
of acid rain.
Scrubber
Carbon Monoxide, CO

COMPLETE COMBUSTION
CxHy (l) + O2 (g) -> CO2 (g) + H2O (g)

INCOMPLETE COMBUSTION
CxHy (l) + O2 (g) -> CO (g) + H2O (g) +VOC (g)
Carbon Monoxide, CO
50 ppm
Impair human reflexes; affect vision
100 ppm
Headache, fatigue, dizziness, shortness of
breath
750 ppm
Unconsciousness, death
Reducing CO Emissions
1.
2.
3.
Post Combustion
Change/Replace Combustion Process
Pre-Combustion
Catalytic Converter
Principles of Environmental Chemistry; by James E Girard;Jones and Bartlett Publisher, Inc; 2005, pg121
Catalytic converters are used to catalyze the conversion of CO to CO2
The converters also reduce the amount of
Volatile Organic Compounds (VOCs) from
tailpipe exhaust
1.11
Volatile Organic Compounds (VOC)

Formed with CO during Incomplete
Combustion

Ways to Reduce are the Same as CO

Precursor to Nitrogen Dioxide, NO2, and
Ozone, O3, Formation
Lead
Sources
1.
•
Tetraethyl lead (TEL) added to gasoline to make
it burn more smoothly, “anti-knocking” agent
Leaded Fuel banned in United States; 1997
2.


Effects
Toxic
Can cause neurological problems in kids
Nitrogen Oxides, NOx
NO, NO2

Low Temperatures
N2 (g) + O2 (g) -> No Reactions

High Temperatures/ High Pressure
1.
2.
N2 (g) + O2 (g) -> 2 NO(g)
NO (g) + O2 (g) -> 2 NO2 (g)
Health Effects of Nitrogen Oxides



Respiratory Irritant-Aggravate conditions like
chronic bronchitis and asthma
Precursor to Ozone, O3, formation
Nitrogen Oxides Dissolve in Water to Make it
Acidic
NO(g) + NO2 (g) + H2O (l)
HNO3 (aq) + HNO2 (aq)
* Unbalanced equation

Low Temperature


Maximize VOC and CO
High Temperature

Maximize NOx
Role of VOC in formation of NO2
Normally, the following reaction is very slow
NO (g) + O2 (g) -> 2 NO2 (g)
VOC’s and the hydroxyl radical (*OH) form an intermediate
which reacts with oxygen to make the above reaction happen
at a faster rate.
Photochemical Air
Pollutants
Secondary Air Pollutants Produced by
Sunlight
Ozone, O3, is a photochemical air pollutant and is formed by….
NOx + Sunlight -> Ozone (Photochemical Pollutants)
VOC + Sunlight -> Ozone (Photochemical Pollutants)
Primary Air Pollutant
Secondary Air Pollutant
NO
NO2
HNO2, HNO3
O3 (photochemical)
http:/www.HowStuffWorks.com
Photochemical Smog
Formation of Photochemical Air
Pollutant; Ozone, O3
1.
NO2 + Sunlight  NO + O
2.
O + O2  O 3
http://www.airnow.gov/index.cfm?action=jump.jump_ozone
Raven/Berg; Environment 4/e, John Wiley and Sons Inc, p 444, Figure 19.7
Problems with Ozone, O3




Lung Irritant,can cause coughing
Makes Eyes Burn
Reacts with Other Air Pollutants (like VOC) to
Make Components of Photochemical Smog
Powerful Oxidizing Agent


Causes rubber to crack
Damages Plants
Ozone Can Contribute to Chemical
Weathering in Automobile Tires
Chemistry; The Science in Context; Thomas R Gilbert, Rein V Kirss, and Geoffrey
Davies, Norton Publishers, 2004.
http:/www.HowStuffWorks.com
Ozone Damaged Plant
http:/www.HowStuffWorks.com
Effect of Season
On Ozone
Concentrations in
Troposphere
Particulate Matter (PM)
Particles of Dispersed
Matter (solid or liquid)
that are larger than
individual molecules
•
•
•
•
•
•
•
Aerosols
Dust
Fumes
Mist/Fog
Smoke, Soot, Ash
Smog
Pollen
PM10; avg diameter less than 10 microns
PM2.5; avg diameter less than 2.5 microns
Effect of Particulate Matter



Impair breathing since small enough to get to
lungs
Reduce visibility since large enough to scatter
light.
Toxic chemicals can adsorb to surface (Cd, Ni,
pesticides)
Reducing Particulate Pollution From
Man-Made Sources
a)
b)
c)
Cyclone Precipitator
Electrostatic Precipitator
Baghouses
Cyclone
Precipitator
Electrostatic
Precipitator
Baghouse
Sources of Air Pollutants
Sources of Air Pollutants
(continued)
Indoor Air Pollution
Combustion
1.
•
•
Indoor VOC
2.
•
3.
NOx, CO, VOC
Cigarettes, burning candles
Paint, fingernail polish, glues…
Radon Gas
Indoor Air Pollutants?
1.14
Indoor Air Pollution
Uranium Radioactive Decay Series
Lead-214
27 minutes
Polonium-218
187 seconds
Radon-222
3.8 days
Radium-226
1600 years
Air
Soil
5 Transformations
Uranium – 238
4.5 billion years
Rock
Infiltration
Of Radon
Gas
Air Pollution Occurrences



The most obvious factor influencing air pollution is the
quantity of contaminants emitted into the atmosphere.
However, when air pollution episodes take place, they are not
generally the result of a drastic increase in the output of
pollutants; instead, they occur because of changes in certain
atmospheric conditions.
Two of the most important atmospheric conditions affecting
the dispersion of pollutants are:


(1) the strength of the wind and
(2) the stability of the air.
Air Mixing




The direct effect of wind speed is to influence the
concentration of pollutants.
Atmospheric stability determines the extent to which vertical
motions will mix the pollution with cleaner air above the
surface layers.
The vertical distance between Earth's surface and the height to
which convectional movements extend is called the mixing
depth.
Generally, the greater the mixing depth, the better the air
quality.
Inversions



Temperature inversions represent a situation in which the
atmosphere is very stable and the mixing depth is significantly
restricted.
When an inversion exists and winds are light, diffusion is
inhibited and high pollution concentrations are to be expected
in areas where pollution sources exist.
Surface temperature inversions form because the ground is a
more effective radiator than the air above. Inversions aloft are
associated with sinking air that characterizes centers of high
air pressure (anticyclones).
Inversion
This is an example
of a generalized
temperature profile
for a surface
inversion.
Temperature-profile
changes in bottom
diagram after the
sun has heated the
surface.
HOW CAN WE STOP AIR
POLLUTION?




Stop producing it in the first place.
Government can pass laws that forbid or limit
the use off chemicals that cause pollution.
Build cars that burn less gasoline.
Recycling helps cut down on pollution.