PowerPoint ® Lecture prepared by Gary A. Beluzo AIR POLLUTION Costs and Benefits of Clean Air 19
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
Copyright © 2007 McGraw-Hill Publishing Company 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
Copyright © 2007 McGraw-Hill Publishing Company Urban Air Pollution Air pollutant Primary Pollutants Secondary Pollutants
Copyright © 2007 McGraw-Hill Publishing Company 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
Copyright © 2007 McGraw-Hill Publishing Company Particulate Matter Mixture of solid particles and liquid droplets Aerosol Dust Fumes Mist Smoke or soot PM 10 PM 2.5
Copyright © 2007 McGraw-Hill Publishing Company Size of Particulates
Copyright © 2007 McGraw-Hill Publishing Company Effects of Particulates Respiratory ailments Bronchitis, pneumonia, emphysema, asthma Implicated in genetic mutations Also alter local climate The “Weekend Effect”
Copyright © 2007 McGraw-Hill Publishing Company Sulfur Dioxide Volcanic eruptions and sea spray Fossil Fuel Combustion Smelting Ores Emitted as SO 2 Health Effects Constrict airways Change respiratory and pulse rates Respiratory diseases 50,000 deaths/year U.S.
Copyright © 2007 McGraw-Hill Publishing Company Acid Deposition SO 3 + H 2 O H 2 SO 4
Copyright © 2007 McGraw-Hill Publishing Company Acid Deposition and Buffering Buffering of acid rain takes place when limestone (CaCO 3 ) supplies bicarbonate ions (HCO 3 - ) The bicarbonate ion (HCO 3 - ) combines with hydrogen ions from the acid deposition CaCO 3 + CO 2 Ca HCO 3 - 2HCO3- + H + CO2 + H 2 O 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.
Copyright © 2007 McGraw-Hill Publishing Company 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
Copyright © 2007 McGraw-Hill Publishing Company Nitrogen Oxides NO, NO 2, NO 3, N 2 O, N 2 O 3, N 2 O 4, and N 2 O 5 Nitric Oxide (NO) and Nitrogen Dioxide (NO 2 ) known as NOx Thermal NOx Fuel NOx NO precursor to many other pollutants
Copyright © 2007 McGraw-Hill Publishing Company Tropospheric O 3 Formation 2NO + O 2 2 NO 2 N 2 + O 2 2NO NO 2 + hv NO + O O + O 2 O 3
Copyright © 2007 McGraw-Hill Publishing Company Nitrogen Oxides and Ozone
Copyright © 2007 McGraw-Hill Publishing Company 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
Copyright © 2007 McGraw-Hill Publishing Company Natural vs. Human Emissions
Copyright © 2007 McGraw-Hill Publishing Company Concentrations Exposure Quantity/volume of air Weight/volume Volume/volume Standard temperature Standard pressure
Copyright © 2007 McGraw-Hill Publishing Company Atmospheric Convection
Copyright © 2007 McGraw-Hill Publishing Company Atmospheric Stability
Copyright © 2007 McGraw-Hill Publishing Company Plume Dispersion
Copyright © 2007 McGraw-Hill Publishing Company Declining U.S. Pollutants
Copyright © 2007 McGraw-Hill Publishing Company Dose Response Function
Copyright © 2007 McGraw-Hill Publishing Company Optimal Level of Air Pollution? The 1970 Clean Air Act Reduction from mobile sources 1990 amendments New stationary source performance standards State Implementation Plan (SIP) Costs of Clean Air Act Benefits of Cleaner Air