Transcript Chapter 23

Bellwork 3/10 * Week 10
Please turn your lab notebooks into TBG
1. What are the two general major
categories/sources of air pollution?
2. Please include examples in your
answers.
Hint: Read
page 526
Air Pollution
Outdoor Air Pollution
Stationary and Mobile
Sources of Air Pollution
• Two Sources of Air Pollution
1. 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.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Sulfur Dioxide (acid rain)
Nitrogen Dioxide / Nitrogen Oxide
Carbon Monoxide
Ozone and Other Photochemical
Oxidants
Volatile Organic Compounds
Particulate Matter
Hydrogen Sulfide
Hydrogen Fluoride
Hazardous Gases
Lead
Outdoor Air Pollutants – Sulfur Dioxide (SO2)
• Properties: colorless gas with irritating odor
• Effects: produces acid rain (H2SO4), breathing
difficulties, eutrophication due to sulfate
formation, lichen and moss are indicators
• Sources: burning high sulfur coal or oil, smelting
or metals, paper manufacture
• Class: sulfur oxides
• EPA Standard: 0.3 ppm (annual mean)
• Combines with water and NH4 to increase soil
fertility
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
Questions
1. 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
Procedure
1. Carbon in coal or oil
burned
2. Unburned carbon -> soot
3. Sulfur in oil and coal
reacts with O2
Chemical Reaction
C + O2 -> CO2
2C + O2 -> CO
C
S + O2 -> SO2
Formation of Industrial Smog
Procedure
4. Sulfur dioxide reacts with O2
to form sulfur trioxide
5. Sulfur trioxide reacts with
H2O
6. Sulfuric acid reacts with
atmospheric ammonia to
form brown, solid
ammonium sulfate
Chemical Reaction
2SO2 + O2 -> 2SO3
SO3 + H2O -> H2SO4
H2SO4 + 2NH3 ->
(NH4)2SO4
Formation of
Photochemical Smog
Formation of
Photochemical Smog
Time
Description
6 - 9 A.M.
Morning commute increases NOx and VOCs
N2 + O2 -> 2 NO
NO + VOC -> NO2
NO2 -UV-> NO + O
9 - 11
A.M
As traffic decreases NOx and VOCs react
2NO + O2 -> 2NO2
Time
Description
11 A.M. As sunlight becomes intense, NO2 breaks down
– 4 P.M.
and Ozone increases
NO2 -UV-> NO + O
O2 + O -> O3
Nitrogen dioxide also forms nitric acid
3NO2 + H2O -> 2 H2NO3 + NO
11 A.M. Nitrogen dioxide also reacts with VOCs released
– 4 P.M.
by autos, industry, etc.
NO2 + VOCs -> 2 PANs
Peroyacyl nitrates (toxic)
4 P.M. - As sun goes down the production of ozone halts
sunset Net 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
Specific Air Pollution Treatment
Technology Continued…
• 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
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
Questions
Read 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, 1Aerosol sprays
Trichloroethane
Dizziness, breathing
irregularities
Asbestos
Pipe insulation,
ceilings, floor tiles,
oven mitts
Lung Cancer and
asbestosis
Benzo-apyrene
Tobacco smoke,
woodstoves
Lung Cancer
Carbon
Monoxide
Faulty furnaces,
cigarette smoke
Headache, heartbeat
irregularities, death, CO
has 250x affinity for Hb
than O2
Major Indoor Pollutants Continued…
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
Paradichlorobenzene
Air fresheners,
mothballs
Cancer
Major Indoor Pollutants Continued…
Radon – 22
Soil and rock near
house foundation,
concrete
Carpets, plastics,
Lung cancer
Tetrachlorethylene
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
Styrene
http://www.metricmind.com/ac_honda/main.htm
Kidney and liver
damage