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What are the two general major categories/sources of air pollution? Hint: Read page 526
What are the two general major categories/sources of air pollution?
Hint: Read page 526
And The Answers Are………• Natural Sources
– Volcanic Ash– Sandstorm Dust– Pollen
• Anthropogenic– Particulates– Oxides of Nitrogen and Sulfur– Greenhouse Gases– VOC
Air Pollution
Outdoor Air Pollution
Stationary and Mobile Sources of Air Pollution
• Two Sources of Air Pollution1. Stationary Sources: have a relatively
fixed location• Point Sources: • Fugitive Sources: • Area Sources:
2. Mobile Sources: move from place to place while emitting pollutants
• Ex) Airplanes
General Effects of Air Pollution
• Visual quality of the environment• Vegetation, Animals, Soil• Water Quality• Natural and Artificial Structures• Human Heath
Human Health & Air Pollution
Primary and Secondary Pollutants, Natural and Human
• Primary Pollutants– Those emitted directly into the air– Hydrocarbons, particulates, etc.
• Secondary Pollutants– Produced through reactions between
primary pollutants and normal atmospheric compounds
– Ozone
Major Air Pollutants
1. Sulfur Dioxide (acid rain)2. Nitrogen Dioxide / Nitrogen Oxide3. Carbon Monoxide4. Ozone and Other Photochemical
Oxidants5. Volatile Organic Compounds6. Particulate Matter7. Hydrogen Sulfide8. Hydrogen Fluoride9. Hazardous Gases10. Lead
Outdoor Air Pollutants – Sulfur Dioxide (SO2)
• PropertiesProperties: : colorless gas with irritating odorcolorless gas with irritating odor• EffectsEffects: : produces acid rain (Hproduces acid rain (H22SOSO44), breathing ), breathing
difficulties, eutrophication due to sulfate difficulties, eutrophication due to sulfate formation, lichen and moss are indicatorsformation, lichen and moss are indicators
• SourcesSources:: burning high sulfur coal or oil, smelting burning high sulfur coal or oil, smelting or metals, paper manufactureor metals, paper manufacture
• ClassClass: : sulfur oxidessulfur oxides• EPA StandardEPA Standard: : 0.3 ppm (annual mean)0.3 ppm (annual mean)• Combines with water and NHCombines with water and NH44 to increase soil to increase soil
fertilityfertility
Outdoor Air Pollutants – Nitrogen Dioxide (NO2)
• Properties: reddish brown gas, formed as fuel burnt in car, strong oxidizing agent, forms Nitric acid in air
• Effects: acid rain, lung and heart problems, decreased visibility (yellow haze), suppresses plant growth
• Sources: fossil fuels combustion, power plants, forest fires, volcanoes, bacteria in soil
• Class: Nitrogen oxides (NOx) • EPA Standard: 0.053 ppm
Outdoor Air Pollutants – Carbon Monoxide (CO)
• Properties: colorless, odorless, heavier than air, 0.0036% of atmosphere
• Effects: binds tighter to Hb than O2 • Sources: incomplete combustion of fossil fuels.
60 - 95% from auto exhaust• Class: carbon oxides (CO2, CO)• EPA Standard: 9 ppm • 5.5 billion tons enter atmosphere/year
Outdoor Air Pollutants – Ozone (O3)
• Properties: colorless, unpleasant odor, major part of photochemical smog
• Effects: lung irritant, damages plants, rubber, fabric, eyes, 0.1 ppm can lower PSN by 50%
• Sources: Created by sunlight acting on NOx and VOC , cars, industry, gas vapors, chemical solvents, fuel combustion products
• Class: photochemical oxidants
Outdoor Air Pollutants – Suspended Particulate Matter (PM10)
• Properties: particles suspended in air (<10 um)• Effects: lung damage, mutagenic, carcinogenic,
teratogenic• Sources: burning coal or diesel, volcanoes,
factories, unpaved roads, plowing, lint, pollen, spores, burning fields
• Class: SPM: dust, soot, asbestos, lead, PCBs, dioxins, pesticides
• EPA Standard: 50 ug/m3 (annual mean)
Size of Selected Particulates
Total Suspended Particulates (TSP)for several large countries
Outdoor Air Pollutants – VOCs (Volatile Organic Compounds)
• Properties: organic compounds that evaporate easily, usually aromatic
• Effects: eye and respiratory irritants; carcinogenic; decreased visibility due to brown haze; liver, CNS, or kidney damage; damages plants
• Sources: evaporation of solvents or fuels, fossil fuels, plants (largest source), aerosols, paint thinners, dry cleaning
• Class: HAPs (Hazardous Air Pollutants)• Concentrations indoors up to 1000x outdoors• 600 million tons of CFCs
Outdoor Air Pollutants – Lead (Pb)
• Properties: grayish metal• Effects: accumulates in tissue; affects kidneys,
liver and nervous system (children most susceptible); mental retardation; possible carcinogen; 20% of inner city kids have [high]
• Sources: particulates, smelters, batteries• Class: toxic or heavy metals• EPA Standard: 1.5 ug/m3
• 2 million tons enter atmosphere/year
US Emissions of Six Major Air Pollutants
Note that there have been significant reductions.
Urban Air Pollution
• Potential for Air Pollution Determined by:– Rate of emission– Downwind distance– Average wind speed– Elevation
• Atmospheric Inversion: – Occurs when warmer air is found
above cooler air and it poses a particular problem when there is a stagnant air mass
Factors that influence Air Pollution formation and intensity
• Local climate (inversions, air pressure, temperature, humidity)
• Topography (hills and mountains)• Population density• Amount of industry• Fuels used by population and industry for heating,
manufacturing, transportation, power• Weather: rain, snow,wind• Buildings (slow wind speed)• Mass transit used• Economics
Questions1. How would you define smog?2. What are the two types of smog and how do they form?
Hint: Read pages 540-541
Smog
• Smog– A mixture between smoke and fog that
produces unhealthy urban air• Two Types
– Sulfurous Smog / Industrial Smog / Fossil Fuels– Photochemical Smog / Sunlight & Pollutants
Formation of Industrial Smog
Formation of Industrial Smog
ProcedureProcedure Chemical ReactionChemical Reaction
1. 1. Carbon in coal or oil Carbon in coal or oil burnedburned
C + OC + O22 CO CO22
2C + O2C + O22 CO CO
2. Unburned carbon 2. Unburned carbon soot soot CC
3. Sulfur in oil and coal 3. Sulfur in oil and coal reacts with Oreacts with O22
S + OS + O22 SO SO22
Formation of Industrial Smog
Procedure Chemical Reaction4. Sulfur dioxide reacts with O2 to form sulfur trioxide
2SO2 + O2 2SO3
5. Sulfur trioxide reacts with H2O
SO3 + H2O H2SO4
6. Sulfuric acid reacts with atmospheric ammonia to form brown, solid ammonium sulfate
H2SO4 + 2NH3 (NH4)2SO4
Formation of Photochemical Smog
Formation of Photochemical Smog
Time Description
6 - 9 A.M. Morning commute increases NOx and VOCsN2 + O2 2 NO
NO + VOC
UV
9 - 11 A.M
As traffic decreases NOx and VOCs react 2NO + O2
Time Description11 A.M. – 4 P.M.
As sunlight becomes intense, NO2 breaks down and Ozone increases
UV
Nitrogen dioxide also forms nitric acid
11 A.M. – 4 P.M.
Nitrogen dioxide also reacts with VOCs released by autos, industry, etc.
VOCs PANs Peroyacyl nitrates (toxic)
4 P.M. - sunset
As sun goes down the production of ozone haltsNet Result: NO + VOC + O2 + UV O3 + PAN
Pollution Control
• Particulates• Automobiles• Sulfur Dioxide
– Coal Gasification: converts coal to gas to remove sulfur
– Scrubbing: gas desulfurization
Air Pollution: Legislation and Standards
• Clean Air Act Amendments of 1990– Comprehensive regulations enacted
by U.S congress that address acid rain, toxic emissions, ozone depletion and automobile exhaust
• Air Quality Standards– Attempt to control air pollution
• Tougher Standards for PM 2.5 and Ozone• Air Quality Index
Specific Air Pollution Treatment Technology
• Traditional– Move factory to remote location– Build taller smokestack so wind blows pollution
elsewhere• New
– Biofiltration : vapors pumped through soil where microbes degrade
– High-energy destruction: high-voltage electricity – Membrane separation: diffusion of organic vapors
through membrane– Oxidation: High temperature combustor
• New continued…– Vapor phase carbon absorption: gases pumped
through series of carbon filled canisters which absorb contaminants
– Electrostatic precipitators: Electrostatically charged surfaces attracts particles
– Sulfur removal: mix crushed limestone with fuel – Nitrogen oxide control: staged burners or
catalytic converters– Hydrocarbon control: closed system to prevent
release before treatment with afterburners– Hybrid, electric and hydrogen powered vehicles
Specific Air Pollution Treatment Technology Continued…
Air Pollution
Indoor Air Pollution
Pathways, Processes and Driving Forces
• Chimney Effect (Stack Effect)– Process whereby warmer air rises in
buildings to upper levels and is replaced in the lower portion of the building by outdoor air drawn through a variety of openings, such as windows doors or cracks in the foundation or walls
Sick Building Syndrome• A condition associated with an
indoor environment that appears to be unhealthy
• The symptoms people report cannot be traced to any one particular cause
Environmental Tobacco Smoke
• Secondhand smoke• 2 sources
– Smoke exhaled by smokers– Smoke emitted from burning tobacco
• The most hazardous indoor pollutant
QuestionsRead a closer look 25.1 (p 562-3) 1. Please explain why radon is a problem?2. Is radon a large hazard? If so why? If not, why?
Hint: Read pages 540-541
Radon Gas
• Radon– Naturally occurring radioactive gas– Colorless, odorless, tasteless– Only identified through proper testing
• Health hazard when leaked into homes
• Exposure is associated with lung cancer
How Radon Enters Houses
Please read page 574 and explain how radon enters houses.
Major Indoor Pollutants
1, 1, 1-Trichloroethane
Aerosol sprays Dizziness, breathing irregularities
Asbestos Pipe insulation, ceilings, floor tiles, oven mitts
Lung Cancer and asbestosis
Benzo pyrene
Tobacco smoke, woodstoves
Lung Cancer
Carbon Monoxide
Faulty furnaces, cigarette smoke
Headache, heartbeat irregularities, death, CO has 250x affinity for Hb than O2
Chloroform Pulp and paper mills, water and wastewater plants
Cancer
Formaldehyde Paneling, particle board, furniture, carpeting, adhesives
Nausea, dizziness, irritation of throat, eyes, and lungs
Methylene chloride
Paint strippers and thinner – persistent
Nerve disorders, diabetes
Nitrogen oxides Furnaces, stoves, fireplaces and vents
Headaches, irritated lungs
Para-dichlorobenzene
Air fresheners, mothballs
Cancer
Major Indoor Pollutants Continued…
http://www.metricmind.com/ac_honda/main.htmhttp://www.metricmind.com/ac_honda/main.htm
Radon – 22 Soil and rock near house foundation, concrete
Lung cancer
Styrene Carpets, plastics, Kidney and liver damage
Tetrachlor- ethylene
Dry-cleaning fluid Nerve disorders, damage to liver and kidneys, cancer
Tobacco Smoke Cigarettes and other smoking sources
Lung cancer and heart disease
Organic Material
Dust mites, fungal and algal spores, dust (human skin), animal dander, hair, carpet fibers, fur
Allergies, coughs, sneezing, eye irritation, sore throats, difficulty breathing
Major Indoor Pollutants Continued…
