Transcript Conformity

Effects and Sources of Air
Pollutants
CE 524
January 2011
Slides noted as AWMA are from: Understanding Air Quality from the Air
and Waste Management Association
Do not make copies of these slides for distribution
Major Provisions of 1970 CAAA
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Established NAAQS
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Primary – allows adequate margin of safety to protect public health
Secondary – protects public from effects of air pollution
• Plants, animals, visibility, public enjoyment of life & property
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Set new source performance standards for new stationary sources
National Emission Standards for Hazardous Air Pollutants
(NESHAPS) applied to existing and new plants
Required states to submit state implementation plans (SIPs)
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Method to set AQ standards for air quality regions within state
Definition of air pollution
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“Air pollution maybe defined as the
presence in the outdoor and/or indoor
atmosphere of one or more contaminants or
combinations thereof in such quantities and
of such duration as may be or may tend to
be injurious to human, plant, or animal life,
or property of which unreasonably interferes
with the comfortable enjoyment of life or
property or conduct of business.
Categories of air pollution
Outdoor
 Indoor
 Occupational
 Personal exposure
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General classification of air
pollutants
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Particulate matter
SOx
NOx
Organic compounds
CO
Halogen compounds
Radioactive compounds
Photochemical oxidants
Other inorganic compounds

What about GHGs, ozone, biological agents?
Air Quality Criteria
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Based on levels to protect human health
 Sensitive members of the population
Developed based on relationship between exposure and
short and long-term health and welfare effects
Effects are expected to occur when pollutant levels exceed
criteria for specified time period
 Short-term -- immediate protection
 Chronic exposure
Pollutant levels cannot legally be exceeded during specific
time period in a specific geographical area
National Emission Standards
Limit amount or concentration of pollutant
emitted from a source
 Helps maintain or improve existing air
quality in a region to meet state or local
standards
 Based on what is achievable with current
technology
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Basis for Regional Standards
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Availability of technology
Presence of monitoring stations
Ability to enforce standards
Understanding of synergistic effects of different
pollutants
Preparation of dispersion model (predicting
ambient concentrations)
Accurate estimates of growth or decline in
industry or population
• Carbon Monoxide (CO)
Criteria
Air
Pollutants
• Hydrocarbons
• Oxides of Nitrogen (NOx)
• Sulfur Dioxide (SO2)
• Particulate Matter (PM10)
• Lead (Pb)
Fundamentals of Air Pollution and Motor Vehicle Emissions
John T. White, EPA
Current NAAQS
Pollutant
CO
Averaging Time
Primary Standard
Secondary Standard
8 hr
9 ppm
Same
1 hr
35 ppm
Same
NO2
Annual average
0.05 ppm
None
SO2
Annual average
0.03 ppm
None
24 hr
0.14 ppm
None
3 hr
None
0.5 ppm
Annual arithmetic
mean
24 hr
50 g/m3
Same
150 g/m3
Same
15 g/m3
Same
Added 1997
Annual arithmetic
mean
24 hr
150 g/m3
Same
Ozone
1 hr
0.12 ppm
Same
8 hr
0.08 ppm
Same
3 months
1.5 g/m3
same
PM10
PM2.5
Lead
Hydrocarbons
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Result when fuel molecules in the engine do not
burn or only partially burn
React in the presence of nitrogen oxides and
sunlight to form ground-level ozone, a major
component of smog
Ozone irritates the eyes, damages the lungs,
and aggravates respiratory problems
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most widespread urban air pollution problem.
A number of exhaust hydrocarbons are also
toxic, with the potential to cause cancer.
Source: EPA 400-F-92-007 August 1994 Fact Sheet OMS-5
Particulate matter
Dispersed airborne solid and liquid
particles (specific size criteria in
chapter)
 Settles out of air at rate which is
function of size and weight (measured
in micrometer µ = 10-4 cm)
 Dust, water vapor, etc
 Affect health and visibility
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• PM10 is a general term for tiny
airborne particles (under ten
microns), e.g., dust, soot, smoke
Particulate
Matter
(PM10)
Also regulating
PM2.5
• Primary sources are fuel-burning
plants and other industrial/
commercial processes
• Some are formed in the air
• They irritate the respiratory system
and may also carry metals,
sulfates, nitrates, etc.
• Some overall decreases seen but
trends may be masked by
meteorological changes
Fundamentals of Air Pollution and Motor Vehicle Emissions
John T. White, EPA
Health Effects of PM
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Particles directly enter respiratory system
Particles themselves may be toxic
Particle may interfere with mechanisms
which clear the respiratory tract
Particle may act as carrier of absorbed toxic
substance
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20 to 60% of particles between 1 and 2.5 µm
breathed will penetrate into lungs
• Enter deep tissue
• This term is used for a number of compounds
containing sulfur
Sulfur
Dioxide
(SO2)
Sulfur
trioxide
• Primarily caused by burning of coal, oil and various
industrial processes
• They can affect the respiratory system
• They react in the atmosphere to form acids, sulfates
and sulfites
• Substantial reductions due to controls at the sources
and through use of low sulfur fuels
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Make up 5 to 20% of total suspended particles
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Major damage to materials
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Contributes to acid rain
Fundamentals of Air Pollution and Motor Vehicle Emissions
John T. White, EPA
• Nitrogen dioxide is the prominent
one (it's the yellow-brown color in
smog)
Oxides
of
Nitrogen
(NOx)
• NOx results from high temperature
combustion processes, e.g. cars
and utilities
• They affect the respiratory system
• They play a major role in atmospheric reactions
• Overall levels unchanged but
transportation sources are cleaner
Fundamentals of Air Pollution and Motor Vehicle Emissions
John T. White, EPA
• Odorless, colorless gas
Carbon
Monoxide
(CO)
• Caused by incomplete combustion of fuel and
air
• Most of it comes from motor vehicles
• Reduces the transport of oxygen through the
bloodstream
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Poses immediate health risk in high
concentrations (> 750 ppm)
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Hemoglobin has 240 times affinity for CO as
for oxygen
• Affects mental functions and visual acuity,
even at low levels
• Improvements are being made but there are
still problems in some urban areas
Fundamentals of Air Pollution and Motor Vehicle Emissions
John T. White, EPA
• Long known as one of the worst
toxics in common use
Lead
(Pb)
• Emitted from gasoline additives,
battery factories and non-ferrous
smelters
• Affects various organs and can
cause sterility and neurological
impairment, e.g. retardation and
behavioral disorders
• Infants and children especially
susceptible
• Control of mobile sources has been
exceptionally successful
Fundamentals of Air Pollution and Motor Vehicle Emissions
John T. White, EPA
• Carbon dioxide
• Chlorofluorocarbons
Other
Air
Pollutants
• Formaldehyde
• Benzene
• Asbestos
• Manganese
• Dioxins
• Cadmium
• Still others which are yet to be
fully characterized
Fundamentals of Air Pollution and Motor Vehicle Emissions
John T. White, EPA
Categories of Air Pollution
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Ambient:
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Indoor
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Air pollution indoors, buildings
EPA studies issues but no federal regulations
Occupational
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air pollution in outdoors
Focus of class
Regulated by EPA
Pollutants in the workplace (mining, chemical operations,
etc)
Regulated by OSHA
Personal exposure
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Persons willful exposure
Cigarette, gases, etc
Climate Change
• Certain gases in the
troposphere absorb some of
the infrared radiation
reflected from the earth
• Carbon Dioxide is the major
one (50%).
• Others include methane
(18%) and CFCs (14%).
CFCs also are responsible
for destroying the
stratospheric ozone layer
• The United States produces
over 20% of the world's
"greenhouse" gases
Fundamentals of Air Pollution and Motor Vehicle Emissions
John T. White, EPA
Mobile Sources
The
CO
Extent
of
VOCs
Air
NOx
Pollution SO2
PM10
Today
Lead
Fundamentals of Air Pollution and Motor Vehicle Emissions
John T. White, EPA
Stationary
Sources
Overall, 54 million metric
tons from mobile sources
in 1990 (43% of total)
63
Who is
Affected by
Air
Pollution?
Over 74 million people are
subjected to high levels of
at least one of these
pollutants
22
19
9
1
Ozone CO
NO2
5
PM10 SO2 Lead
Millions of people living in counties with
air quality that exceeds each NAAQS
(1990 data)
Fundamentals of Air Pollution and Motor Vehicle Emissions
John T. White, EPA
World wide
WHO indicates that 2.4 million people
die from causes directly attributable to
air pollution
 More than for car accidents
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Visibility
Although not a pollutant, visibility is a
major pollution concern
 Haze
 Smog
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Air Toxics
Get information from EPA
 Example - http://epa.gov/otaq/toxics.htm
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When is it a problem
Classified as pollutant once their
presence results in damage to
humans, plants, animals or materials
 Concentration
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1 volume of gaseous pollutant = 1 ppm
106 volumes (pollutant + air)
0.0001 percent by volume = 1 ppm