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; N 2 ; 78 %; Oxygen; O 2 ; 21 % Argon; Ar; 0.9 %; Other Gases; 0.1 % O 2 Ar Nitrogen Oxygen Argon Other N 2

Composition of the other gasses

Gas Argon (Ar) CO 2 Ne He CH 4 Kr H 2 % volume 0.934% 350 mmv 18.18 ppmv 5.24 ppmv 1.7 ppmv 1.14 ppmv 0.55 ppmv

One Breath has 2.0 X 10

22

molecules 20 000 000 000 000 000 000 000

How many N 2 molecules Are in a breath of air?

Ozone (O

3

)

If one breath of air contains 2 x 10 22 molecules and atoms, and the acceptable ozone level is 0.12 ppm, how many molecules of O 3 are in each breath?

2 x 10 22 molecules and atoms in a breath of air x 0.12 O 3 molecules 1 x 10 6 molecules and atoms in air = 2 x 10 15 O 3 molecules in a breath How many oxygen

atoms

are in each breath?

2 x 10 15 O 3 molecules x 3 O atoms___ 1 O 3 molecules = 6 x 10 15 O atoms 1.12

When people breathe What’s in a Breath?

Typical Composition of Inhaled and Exhaled Air

Substance

Nitrogen Oxygen Argon Carbon dioxide

Inhaled air (%)

78.0

21.0

0.9

0.04

Exhaled air (%)

75.0

16.0

0.9

4.0

Water 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 10 6 molecules of air

Parts per billion (ppb)

Sulfur dioxide in the air should not exceed 30 ppb = 30 sulfur dioxide molecules 1 x 10 9 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 means 210,000 parts per million

The difference between pph and ppm is a factor of 10,000 Try Chapter 1 Figures Alive! for practice

1.2

Classifying Matter All Matter Pure Substances NO Can it be separated by YES a physical process?

Mixtures NO Elements Can it be broken down into simpler ones by

chemical means

?

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 cocaine water

element compound compound

fluorine table salt soap sea water

element compound mixture mixture

1.6

Group

The Periodic Table

Period

A space filling model for a water molecule, H 2 O Oxygen atom Two hydrogen atoms A molecule is a combination of a fixed number of atoms held together in a certain spatial arrangement.

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 H 2 N 2 O 2 Cl 2 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 2 mono di 3 4 tri tetra 5 6 7 8 9 10 penta hexa hepta octa nona deca 1.8

Chemical Equations

 Reactant(s) -> Product(s)  Carbon + Oxygen -> Carbon Dioxide  C (s) + O 2 (g) -> CO 2 (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 + O 2 reactants CO 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 + O 2 2 CO (balanced) 2 carbon atoms 2 oxygen atoms two carbon atoms two oxygen atoms 1.9

2 C + O 2 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

C 3 H C 3 H 8 8 + O

3 C atoms 8 H atoms 10 O atoms

2 + 5 O 2 CO 2 + H 2 O 3 CO 2 + 4 H 2 O

3 C atoms 8 H atoms 10 O atoms 1.9

Direct Source of Sulfur Trioxide Coal + O 2 (1-3% sulfur) 2 SO 2 + O 2 SO 2 2 SO 3 Good News: Since 1985 we have seen a 25% reduction in SO 2 emissions in the U.S.

1.11

Direct Source of Nitrogen Oxides N 2 + O 2 + high temp 2 NO (nitrogen oxide)

High temperatures from auto engine or coal-fired power plant

NO is very reactive: 2 NO + O 2 2 NO 2

Simplified version of chemistry that occurs

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

When the AQI is in this range:

0  50 51 – 100 101 – 150 151 201 301 – – – 200 300 500

Levels of Health Concern

...air quality conditions are:

Good Moderate Unhealthy for sensitive groups Unhealthy Very unhealthy Hazardous

Colors

...as symbolized by this color:

Green Yellow Orange Red Purple Maroon 1.3

Indonesian Air Quality Index (indeks standar pencemaran udara =ISPU)

 Pollutant parameters : 

Carbon monoksida (CO)

   

Nitrogen (NO 2 ) Ozone (O 3 ) Sulfur dioxide (SO 2 ) Particulate Matter (PM10)

Hubungan ISPU dan kondisi lingkungan

Kategori Baik Sedang Tidak Sehat Sangat Tidak Sehat Rentang

0-50 51 - 100 101 - 199 200-299

Berbahaya

300 - lebih

Karbon monoksida (CO) Nitrogen (NO 2 ) Ozon (O 3 )

Tidak ada efek Sedikit berbau Luka pada Beberapa spesies tumbuhan akibat kombinasi dengan SO 2 (Selama 4 Jam) Perubahan kimia darah tapi tidak terdeteksi Berbau Luka pada Beberapa spesies tumbuhan 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 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 paru paru kronis Tingkat yang berbahaya bagi semua populasi yang terpapar

Sulfur dioksida (SO 2 )

Luka pada Beberapa spesies tumbuhan akibat kombinasi dengan O 3 (Selama 4 Jam)

Partikulat

Tidak ada efek Luka pada Beberapa spesies tumbuhan Terjadi penurunan pada jarak pandang Bau, Meningkatnya kerusakan tanaman Jarak pandang turun dan terjadi pengotoran debu di mana-mana Meningkatnya sensitivitas pada pasien berpenyakit asma dan bronchitis Meningkatnya sensitivitas pada pasien berpenyakit asma dan bronchitis

 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, SO

x

SO

2

, SO

3

When coal is burned, so is the Sulfur impurity S + O 2 SO 2

The SO

2

then burns to produce SO

3

.

2 SO 2 + 1 O 2 2 SO 3

SO

3

gas then dissolve in water to make a component of acid rain, H

2

SO

4

(aq).

SO 3 (g) + H 2 O (l) H 2 SO 4 (aq) In general; nonmetal oxides dissolve in water to make it acidic

Problems with SO

x

1.

2.

SO x are respiratory irritants SO x dissolve in water to make a component of acid rain.

Scrubber

Carbon Monoxide, CO

 COMPLETE COMBUSTION C x H y (l) + O 2 (g) -> CO 2 (g) + H 2 O (g)  INCOMPLETE COMBUSTION C x H y (l) + O 2 (g) -> CO (g) + H 2 O (g) +VOC (g)

Carbon Monoxide, CO

50 ppm 100 ppm 750 ppm Impair human reflexes; affect vision Headache, fatigue, dizziness, shortness of breath 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 CO 2 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, NO 2 , and Ozone, O 3 , Formation

Lead

1.

• Sources Tetraethyl lead (TEL) added to gasoline to make it burn more smoothly, “anti-knocking” agent 2.

  Leaded Fuel banned in United States; 1997 Effects Toxic Can cause neurological problems in kids

Nitrogen Oxides, NO

x

NO, NO

2

 Low Temperatures N 2 (g) + O 2 (g) -> No Reactions  High Temperatures/ High Pressure 1.

2.

N 2 (g) + O 2 (g) -> 2 NO(g) NO (g) + O 2 (g) -> 2 NO 2 (g)

Health Effects of Nitrogen Oxides

 Respiratory Irritant-Aggravate conditions like chronic bronchitis and asthma   Precursor to Ozone, O 3 , formation Nitrogen Oxides Dissolve in Water to Make it Acidic NO(g) + NO 2 (g) + H 2 O (l) HNO 3 (aq) + HNO 2 (aq) * Unbalanced equation

 Low Temperature  Maximize VOC and CO  High Temperature  Maximize NO x

Role of VOC in formation of NO

2

Normally, the following reaction is very slow NO (g) + O 2 (g) -> 2 NO 2 (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, O 3 , is a photochemical air pollutant and is formed by….

NO x + Sunlight -> Ozone (Photochemical Pollutants) VOC + Sunlight -> Ozone (Photochemical Pollutants)

Primary Air Pollutant NO Secondary Air Pollutant NO 2 HNO 2 , HNO 3 O 3 (photochemical)

http:/www.HowStuffWorks.com

Photochemical Smog

Formation of Photochemical Air Pollutant; Ozone, O

3

1.

NO 2 + Sunlight  NO + O 2.

O + O 2  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, O

3

 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 PM 10 ; avg diameter less than 10 microns PM 2.5

; 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

1.

2.

3.

• • Combustion NO x , CO, VOC Cigarettes, burning candles • Indoor VOC 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 5 Transformations Uranium – 238 4.5 billion years Air Soil 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.