Effects and Sources of Air Pollutants

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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
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Major Provisions of 1970 CAAA

• Established NAAQS
• 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
• 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)
• Method to set AQ standards for air quality
  regions within state

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Definition of air pollution

• 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.

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Categories of air pollution

• Outdoor
• Indoor
• Occupational
• Personal exposure

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General classification of air pollutants

• Particulate matter
• SOx
• NOx
• Organic compounds
• CO
• Halogen compounds
• Radioactive compounds
• Photochemical oxidants
• Other inorganic compounds
• What about GHGs, ozone, biological agents?

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Air Quality Criteria

• 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

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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

• 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

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Criteria AirPollutants

• Carbon Monoxide (CO)
• 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
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Current NAAQS
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Hydrocarbons

• 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
• 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
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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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ParticulateMatter(PM10)Also regulating PM2.5

• PM10 is a general term for tiny airborne
  particles (under ten microns), e.g., dust, soot,
  smoke
• 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
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Health Effects of PM

• 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
• 20 to 60 of particles between 1 and 2.5 µm
  breathed will penetrate into lungs
• Enter deep tissue

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SulfurDioxide(SO2)Sulfur trioxide

• This term is used for a number of compounds
  containing sulfur
• 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
• Make up 5 to 20 of total suspended particles
• Major damage to materials
• Contributes to acid rain

Fundamentals of Air Pollution and Motor Vehicle
Emissions John T. White, EPA
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Oxidesof Nitrogen(NOx)

• Nitrogen dioxide is the prominent one (it's the
  yellow-brown color in smog)
• NOx results from high temperature combustion
  processes, e.g. cars and utilities
• They affect the respiratory system
• They play a major role in atmos- pheric
  reactions
• Overall levels unchanged but transportation
  sources are cleaner

Fundamentals of Air Pollution and Motor Vehicle
Emissions John T. White, EPA
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CarbonMonoxide(CO)

• Odorless, colorless gas
• Caused by incomplete combustion of fuel and air
• Most of it comes from motor vehicles
• Reduces the transport of oxygen through the
  bloodstream
• Poses immediate health risk in high
  concentrations (gt 750 ppm)
• 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
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Lead(Pb)

• Long known as one of the worst toxics in common
  use
• 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
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OtherAirPollutants

• Carbon dioxide
• Chlorofluorocarbons
• 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
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Categories of Air Pollution

• Ambient
• air pollution in outdoors
• Focus of class
• Regulated by EPA
• Indoor
• Air pollution indoors, buildings
• EPA studies issues but no federal regulations
• Occupational
• Pollutants in the workplace (mining, chemical
  operations, etc)
• Regulated by OSHA
• Personal exposure
• Persons willful exposure
• Cigarette, gases, etc

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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
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TheExtentofAirPollutionToday
Overall, 54 million metric tons from mobile
sources in 1990 (43 of total)
Fundamentals of Air Pollution and Motor Vehicle
Emissions John T. White, EPA
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Who isAffected byAir Pollution?
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Over 74 million people are subjected to high
levels of at least one of these pollutants
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Ozone CO NO2 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
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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
• 1 volume of gaseous pollutant 1 ppm
• 106 volumes (pollutant air)
• 0.0001 percent by volume 1 ppm