powerpoint ® lecture prepared by gary a. beluzo air pollution costs and benefits of clean air 19
TRANSCRIPT
Copyright © 2007 McGraw-Hill Publishing Company
STUDENT LEARNING OUTCOMES
• Describe the factors that determine the atmospheric concentration of air pollutants.
• Compare and contrast the advantages and disadvantages of reducing air pollution via command and control versus market based mechanisms.
• Explain why zero emissions may not be economically efficient and may not be necessary to protect sensitive groups from its effects.
• Explain the benefits and costs of reducing air pollution and describe their relative size.
After reading this chapter, students will be able to
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A Trip to Guangzhou, China
• Trip to validate results of satellite image analysis
• How quickly is agricultural land being converted to urban uses?
• Increase of 300% in 9 years
• Guangzhou is so polluted that it blocks out the sun
• People wear surgical masks outdoors
• While in the city the author did not see the sun
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Urban Air Pollution
• Air pollutant
• Primary Pollutants
• Secondary Pollutants
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Carbon Monoxide• Colorless, odorless
• Incomplete combustion
• Mobile sources
• Stationary sources
• Binds strongly with hemoglobin
• Headaches, dizziness, and death
• 35 ppb per hour
• May also contribute to global climate change
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Particulate Matter• Mixture of solid particles and
liquid droplets
• Aerosol• Dust
• Fumes
• Mist
• Smoke or soot
• PM 10
• PM 2.5
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Effects of Particulates• Respiratory ailments
• Bronchitis, pneumonia, emphysema, asthma
• Implicated in genetic mutations
• Also alter local climate
• The “Weekend Effect”
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Sulfur Dioxide• Volcanic eruptions and
sea spray
• Fossil Fuel Combustion
• Smelting Ores
• Emitted as SO2
• Health Effects• Constrict airways
• Change respiratory and pulse rates
• Respiratory diseases
• 50,000 deaths/year U.S.
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Acid Deposition and Buffering• Buffering of acid rain takes place when limestone
(CaCO3) supplies bicarbonate ions (HCO3-)
• The bicarbonate ion (HCO3-) combines with hydrogen
ions from the acid deposition
CaCO3 + CO2 Ca++ + 2HCO3-
2HCO3- + H+ CO2 + H2O
• In areas that have large amounts of calcium carbonate such as western U.S., little effect will occur.
• In other areas, such as New England or upstate NY, acid precipitation quickly lowers pH.
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Effects of Acid Deposition
• Lowering pH reduces reproductive success of aquatic organisms
• Lower pH also reduces the nutrient holding capacity of soils
• Metallic ions, such as aluminum, can be released from soil to kill freshwater fish
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Nitrogen Oxides
• NO, NO2, NO3, N2O, N2O3, N2O4, and N2O5
• Nitric Oxide (NO) and Nitrogen Dioxide (NO2) known as NOx
• Thermal NOx
• Fuel NOx
• NO precursor to many other pollutants
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Tropospheric O3 Formation
2NO + O2 2 NO2
N2 + O2 2NO
NO2 + hv NO + O
O + O2 O3
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Hydrocarbons• Carbon and hydrogen
• Incomplete fuel combustion
• Evaporation of fuel
• VOCs
• Natural and anthropogenic sources
• Carcinogens
• React with many other pollutants to form photochemical smog
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Concentrations
• Exposure
• Quantity/volume of air
• Weight/volume
• Volume/volume
• Standard temperature
• Standard pressure