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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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Presentasi berjudul: "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?"— Transcript presentasi:

1 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? Catatan: Diambil dari berbagai sumber

2 Where are we leaving ?

3

4 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

5 Air Composition Nitrogen; N 2 ; 78 %; Oxygen; O 2 ; 21 % Nitrogen; N 2 ; 78 %; Oxygen; O 2 ; 21 % Argon; Ar; 0.9 %; Other Gases; 0.1 % Argon; Ar; 0.9 %; Other Gases; 0.1 % N2N2 O2O2 Ar

6 Composition of the other gasses Gas % volume Argon (Ar) 0.934% CO mmv Ne ppmv He 5.24 ppmv CH 4 Kr H ppmv 1.14 ppmv 0.55 ppmv

7 One Breath has 2.0 X molecules How many N 2 molecules Are in a breath of air?

8 Ozone (O 3 ) If one breath of air contains 2 x molecules and atoms, and the acceptable ozone level is 0.12 ppm, how many molecules of O 3 are in each breath? 2 x 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 O 3 molecules in a breath How many oxygen atoms are in each breath? 2 x O 3 molecules x 3 O atoms___ 1 O 3 molecules = 6 x O atoms 1.12

9 When people breathe Substance Inhaled air (%) Exhaled air (%) Nitrogen Oxygen Argon Carbon dioxide Water Typical Composition of Inhaled and Exhaled Air What’s in a Breath?

10 Concentration Terms Parts per hundred (percent) Parts per million (ppm) Parts per billion (ppb) Atmosphere is 21% oxygen = 21 oxygen molecules per 100 molecules of air Midday ozone levels reach about 0.4 ppm = 0.4 ozone molecules 1 x 10 6 molecules of air Sulfur dioxide in the air should not exceed 30 ppb = 30 sulfur dioxide molecules 1 x 10 9 molecules of air 1.2

11 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

12 Classifying Matter All Matter Pure Substances Mixtures Can it be separated by a physical process? CompoundsElements YES NO Can it be broken down into simpler ones by chemical means? NOYES 1.6

13 Three States of Matter 1.5 Matter - anything that occupies space and has mass.

14 Classifying Matter Classify each of these as an element, a compound, or a mixture: carbon dioxide nickel cocaine water compound element compound fluorine table salt soap sea water element compound mixture 1.6

15 Group Period The Periodic Table

16 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

17 Many nonmetals occur as diatomic (made up of two atoms) molecules H2H2 N2N2 O2O2 Cl 2 1.7

18 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

19 2. Prefixes are used to designate the number of each type of element: Naming Binary Compounds number of atomsprefix 1mono 2di 3tri 4tetra 5penta 6hexa 7hepta 8octa 9nona 10deca 1.8

20 Chemical Equations Reactant(s) -> Product(s) Reactant(s) -> Product(s) Carbon + Oxygen -> Carbon Dioxide Carbon + Oxygen -> Carbon Dioxide C (s) + O 2 (g) -> CO 2 (g) 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

21 Chemical reactions are characterized by the rearrangement of atoms when reactants are transformed into products C + O 2 CO reactants product 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 atomstwo carbon atoms 2 oxygen atomstwo oxygen atoms This is an example of a combustion reaction 1.9

22 + 2 C + O 2 2 CO 1.9

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24 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 8 + O 2 CO 2 + H 2 O C 3 H O 2 3 CO H 2 O 3 C atoms 8 H atoms 10 O atoms 3 C atoms 8 H atoms 10 O atoms 1.9

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

26 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

27 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

28 Quality of The Air Air Quality Index (AQI) : USA ng Kong, China, Malaysia Air Pollution Index (API) : Hong Kong, China, Malaysia Indeks Standar Pencamaran Udara (ISPU) : Indeks Standar Pencamaran Udara (ISPU) : (Air Pollution Standard Index /APSI) (Air Pollution Standard Index /APSI) Indonesia Indonesia

29 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

30 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:...as symbolized by this color: 0  50 GoodGreen 51 – 100ModerateYellow 101 – 150Unhealthy for sensitive groups Orange 151 – 200UnhealthyRed 201 – 300Very unhealthyPurple 301 – 500HazardousMaroon 1.3

31 Indonesian Air Quality Index (indeks standar pencemaran udara =ISPU) Pollutant parameters : Pollutant parameters : Carbon monoksida (CO) Carbon monoksida (CO) Nitrogen (NO 2 ) Nitrogen (NO 2 ) Ozone (O 3 ) Ozone (O 3 ) Sulfur dioxide (SO 2 ) Sulfur dioxide (SO 2 ) Particulate Matter (PM10) Particulate Matter (PM10)

32 Hubungan ISPU dan kondisi lingkungan KategoriRentang Karbon monoksida (CO) Nitrogen (NO 2 ) Ozon (O 3 ) Sulfur dioksida (SO 2 ) Partikulat Baik0-50 Tidak ada efek Sedikit berbau Luka pada Beberapa spesies tumbuhan akibat kombinasi dengan SO 2 (Selama 4 Jam) Luka pada Beberapa spesies tumbuhan akibat kombinasi dengan O 3 (Selama 4 Jam) Tidak ada efek Sedang Perubahan kimia darah tapi tidak terdeteksi Berbau Luka pada Beberapa spesies tumbuhan Terjadi penurunan pada jarak pandang Tidak Sehat 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 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 Meningkatnya sensitivitas pada pasien berpenyakit asma dan bronchitis Berbahaya lebih Tingkat yang berbahaya bagi semua populasi yang terpapar

33 API- Malaysia API- Malaysia 0-50 Good Moderate Unhealthy Very unhealthy 301- Hazardous

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35 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. 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: Pollutants can be grouped into two categories: (1) primary pollutants, which are emitted directly from identifiable sources, and (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. (2) secondary pollutants, which are produced in the atmosphere when certain chemical reactions take place among primary pollutants.

36 Primary Pollutants The major primary pollutants include: particulate matter (PM), particulate matter (PM), sulfur dioxide, sulfur dioxide, nitrogen oxides, nitrogen oxides, volatile organic compounds (VOCs), volatile organic compounds (VOCs), carbon monoxide, and carbon monoxide, and lead. lead.

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39 Secondary Pollutants Atmospheric sulfuric acid is one example of a secondary pollutant. Atmospheric sulfuric acid is one example of a secondary pollutant. Air pollution in urban and industrial areas is often called smog. 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. 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. 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. Although considerable progress has been made in controlling air pollution, the quality of the air we breathe remains a serious public health problem.

40 Major Sources of Air Pollutants Combustion of coal in coal burning power plants 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. Combustion of fuel in car, trucks, and other vehicles.

41 Sulfur Oxides, SO x SO 2, SO 3 When coal is burned, so is the Sulfur impurity S + O 2 SO 2

42 The SO 2 then burns to produce SO 3. 2 SO O 2 2 SO 3

43 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

44 Problems with SO x 1. SO x are respiratory irritants 2. SO x dissolve in water to make a component of acid rain.

45 Scrubber

46 Carbon Monoxide, CO COMPLETE COMBUSTION COMPLETE COMBUSTION C x H y (l) + O 2 (g) -> CO 2 (g) + H 2 O (g) INCOMPLETE COMBUSTION INCOMPLETE COMBUSTION C x H y (l) + O 2 (g) -> CO (g) + H 2 O (g) +VOC (g)

47 Carbon Monoxide, CO 50 ppm Impair human reflexes; affect vision 100 ppm Headache, fatigue, dizziness, shortness of breath 750 ppm Unconsciousness, death

48 Reducing CO Emissions 1. Post Combustion 2. Change/Replace Combustion Process 3. Pre-Combustion

49 Catalytic Converter Principles of Environmental Chemistry; by James E Girard;Jones and Bartlett Publisher, Inc; 2005, pg121

50 1.11 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

51 Volatile Organic Compounds (VOC) Formed with CO during Incomplete Combustion Formed with CO during Incomplete Combustion Ways to Reduce are the Same as CO Ways to Reduce are the Same as CO Precursor to Nitrogen Dioxide, NO 2, and Ozone, O 3, Formation Precursor to Nitrogen Dioxide, NO 2, and Ozone, O 3, Formation

52 Lead 1. Sources Tetraethyl lead (TEL) added to gasoline to make it burn more smoothly, “anti-knocking” agent Tetraethyl lead (TEL) added to gasoline to make it burn more smoothly, “anti-knocking” agent 2. Effects Toxic Toxic Can cause neurological problems in kids Can cause neurological problems in kids Leaded Fuel banned in United States; 1997

53 Nitrogen Oxides, NO x NO, NO 2 Low Temperatures Low Temperatures N 2 (g) + O 2 (g) -> No Reactions High Temperatures/ High Pressure High Temperatures/ High Pressure 1. N 2 (g) + O 2 (g) -> 2 NO(g) 2. NO (g) + O 2 (g) -> 2 NO 2 (g)

54 Health Effects of Nitrogen Oxides Respiratory Irritant-Aggravate conditions like chronic bronchitis and asthma Respiratory Irritant-Aggravate conditions like chronic bronchitis and asthma Precursor to Ozone, O 3, formation Precursor to Ozone, O 3, formation Nitrogen Oxides Dissolve in Water to Make it Acidic 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

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

56 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.

57 Photochemical Air Pollutants Secondary Air Pollutants Produced by Sunlight NO x + Sunlight -> Ozone (Photochemical Pollutants) VOC + Sunlight -> Ozone (Photochemical Pollutants) Ozone, O 3, is a photochemical air pollutant and is formed by….

58 Primary Air Pollutant Secondary Air Pollutant NONO 2 HNO 2, HNO 3 O 3 (photochemical)

59 Photochemical Smog

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61 Formation of Photochemical Air Pollutant; Ozone, O 3 1. NO 2 + Sunlight  NO + O 2. O + O 2  O 3

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63 Raven/Berg; Environment 4/e, John Wiley and Sons Inc, p 444, Figure 19.7

64 Problems with Ozone, O 3 Lung Irritant,can cause coughing Lung Irritant,can cause coughing Makes Eyes Burn Makes Eyes Burn Reacts with Other Air Pollutants (like VOC) to Make Components of Photochemical Smog Reacts with Other Air Pollutants (like VOC) to Make Components of Photochemical Smog Powerful Oxidizing Agent Powerful Oxidizing Agent Causes rubber to crack Causes rubber to crack Damages Plants Damages Plants

65 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.

66 Ozone Damaged Plant

67 Effect of Season On Ozone Concentrations in Troposphere

68 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

69 Effect of Particulate Matter Impair breathing since small enough to get to lungs Impair breathing since small enough to get to lungs Reduce visibility since large enough to scatter light. Reduce visibility since large enough to scatter light. Toxic chemicals can adsorb to surface (Cd, Ni, pesticides) Toxic chemicals can adsorb to surface (Cd, Ni, pesticides)

70 Reducing Particulate Pollution From Man-Made Sources a) Cyclone Precipitator b) Electrostatic Precipitator c) Baghouses

71 Cyclone Precipitator

72 Electrostatic Precipitator

73 Baghouse

74 Sources of Air Pollutants

75 Sources of Air Pollutants (continued)

76 Indoor Air Pollution 1. Combustion NO x, CO, VOC NO x, CO, VOC Cigarettes, burning candles Cigarettes, burning candles 2. Indoor VOC Paint, fingernail polish, glues… Paint, fingernail polish, glues… 3. Radon Gas

77 1.14 Indoor Air Pollutants?

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79 Indoor Air Pollution

80 Uranium Radioactive Decay Series Rock 5 Transformations Soil Uranium – billion years Radium years Air Radon days Polonium seconds Lead minutes

81 Infiltration Of Radon Gas

82 Air Pollution Occurrences The most obvious factor influencing air pollution is the quantity of contaminants emitted into the atmosphere. 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. 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: Two of the most important atmospheric conditions affecting the dispersion of pollutants are: (1) the strength of the wind and (1) the strength of the wind and (2) the stability of the air. (2) the stability of the air.

83 Air Mixing The direct effect of wind speed is to influence the concentration of pollutants. 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. 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. 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. Generally, the greater the mixing depth, the better the air quality.

84 Inversions Temperature inversions represent a situation in which the atmosphere is very stable and the mixing depth is significantly restricted. 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. 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). 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).

85 Inversion

86 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.

87 HOW CAN WE STOP AIR POLLUTION? Stop producing it in the first place. Stop producing it in the first place. Government can pass laws that forbid or limit the use off chemicals that cause pollution. Government can pass laws that forbid or limit the use off chemicals that cause pollution. Build cars that burn less gasoline. Build cars that burn less gasoline. Recycling helps cut down on pollution. Recycling helps cut down on pollution.


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