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					Human Impact on the
   Atmosphere
                     Chapters 18 and 19
       Living in the Environment, 11th Edition, Miller




Advanced Placement Environmental Science
             La Canada High School
                           Dr. E
                                        Pollution
    Thorpe, Gary S., M.S., (2002). Barron’s How to prepare for the AP Environmental Science Advanced Placement Exam

• The term “Smog” (smoke and fog) was first
  used in 1905 to describe sulfur dioxide
  emission
• In 1952, severe pollution took the lives of
  5000 people in London
• “It isn’t pollution that’s harming the
  environment. It’s the impurities in our air and
  water that are doing it.”
                                               Former U.S. Vice President Dan Quayle
  www.aqmd.gov/pubinfo/ 97annual.html
        Congress found:
        • Most people now live in urban areas
        • Growth results in air pollution
 The    • Air pollution endangers living things

Clean   It decided:
 Air    • Prevention and control at the source was
           appropriate
 Act    • Such efforts are the responsibility of states
           and local authorities
        • Federal funds and leadership are essential
           for the development of effective
           programs
           Clean Air Act
• Originally signed 1963
  – States controlled standards
• 1970 – Uniform Standards by Federal
  Govt.
  – Criteria Pollutants
    • Primary – Human health risk
    • Secondary – Protect materials, crops,
      climate, visibility, personal comfort
               Clean Air Act
• 1990 version
  – Acid rain, urban smog, toxic air pollutants, ozone
    depletion, marketing pollution rights, VOC’s
• 1997 version
  –   Reduced ambient ozone levels
  –   Cost $15 billion/year -> save 15,000 lives
  –   Reduce bronchitis cases by 60,000 per year
  –   Reduce hospital respiratory admission 9000/year
Outdoor Air Pollution
Major Sources of Primary Pollutants
Stationary Sources
• Combustion of fuels for power and heat – Power Plants
• Other burning such as Wood & crop burning or forest
  fires
• Industrial/ commercial processes
• Solvents and aerosols
Mobile Sources
• Highway: cars, trucks, buses and motorcycles
• Off-highway: aircraft, boats, locomotives, farm
  equipment, RVs, construction machinery, and lawn
  mowers
54 million metric
tons from mobile
sources in 1990
  Human Impact on Atmosphere
• Burning Fossil Fuels  Adds CO2 and O3 to troposphere
                        Global Warming
                        Altering Climates
                        Produces Acid Rain

• Using Nitrogen        Releases NO, NO2, N2O, and NH3
  fertilizers and        into troposphere
  burning fossil fuels  Produces acid rain

• Refining petroleum  Releases SO into troposphere
                                   2
  and burning fossil
  fuels
• Manufacturing       Releases toxic heavy metals (Pb,
                       Cd, and As) into troposphere
   www.dr4.cnrs.fr/gif-2000/ air/products.html
   Criteria Air Pollutants
EPA uses six "criteria pollutants" as indicators of
air quality
    1.   Nitrogen Dioxide: NO2
    2.   Ozone: ground level O3
    3.   Carbon monoxide: CO
    4.   Lead: Pb
    5.   Particulate Matter: PM10 (PM 2.5)
    6.   Sulfur Dioxide: SO2
    •    Volatile Organic Compounds: (VOCs)
EPA established for each concentrations above
which adverse effects on health may occur
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 @ higher
  temperatures, power plants, forest fires,
  volcanoes, bacteria in soil
• Class: Nitrogen oxides (NOx)
• EPA Standard: 0.053 ppm
Mobile Source Emissions:
   Nitrogen Oxides
            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 , photocopiers, cars,
  industry, gas vapors, chemical solvents,
  incomplete fuel combustion products
• Class: photochemical oxidants
            Ozone (O3)
• 10,000 to 15,000 people in US admitted to
  hospitals each year due to ozone-related
  illness
• Children more susceptible
  – Airways narrower
  – More time spent outdoors
Mobile Source Emissions:
   Hydrocarbons –
 Precursors to Ozone
Carbon Monoxide (CO)
• Properties: colorless, odorless, heavier than
  air, 0.0036% of atmosphere
• Effects: binds tighter to Hb than O2, mental
  functions and visual acuity, even at low levels
• 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
Mobile Source
Emissions - CO
              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
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)
Mobile Source Emissions: Fine
 Particulate Matter (PM2.5)
    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
  VOCs (Volatile Organic Compounds)
• Properties: organic compounds (hydrocarbons) that
  evaporate easily, usually aromatic
• Effects: eye and respiratory irritants; carcinogenic;
  liver, CNS, or kidney damage; damages plants; lowered
  visibility due to brown haze; global warming
• Sources: vehicles (largest source), evaporation of
  solvents or fossil fuels, aerosols, paint thinners, dry
  cleaning
• Class: HAPs (Hazardous Air Pollutants)
  – Methane
  – Benzene
  – Chlorofluorocarbons (CFCs), etc.
• Concentrations indoors up to 1000x outdoors
      Other Air Pollutants
•   Carbon dioxide
•   ChloroFluoroCarbons
•   Formaldehyde
•   Benzene
•   Asbestos
•   Manganese
•   Dioxins
•   Cadmium
•   Others not yet fully characterized
           Formation & Intensity
Factors
• 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
           Smog Forms
...when polluted air is stagnant
    (weather conditions, geographic location)




                Los Angeles, CA
               Primary Pollutants

                     CO CO2                  Secondary Pollutants
                   SO2 NO NO2                      SO3
               Most hydrocarbons                   HNO3    H2SO4
                Most suspended                   H 2 O2   O3   PANs
                    particles
                                         Most NO3 and SO2 – salts
                                                –
                                                        4



Natural
              Sources               Stationary

          Mobile
      Photochemical Smog
                     UV radiation


Primary Pollutants                  Secondary Pollutants

NO2 + Hydrocarbons                       HNO3      O3
                      H2O + O2       nitric acid ozone


Auto Emissions                      Photochemical Smog
Air Pollution Results
Indoor Air Pollution
        Why is indoor air quality
              important?
• 70 to 90% of time spent indoors, mostly at home
• Many significant pollution sources in the home (e.g.
  gas cookers, paints and glues)
• Personal exposure to many common pollutants is
  driven by indoor exposure
• Especially important for susceptible groups – e.g. the
  sick, old and very young
               Exposure
• Time spent in various environments in US
  and less-developed countries
  House of Commons Select Committee
 Enquiry on Indoor Air Pollution (1991)
• “[There is] evidence that 3 million people have asthma in
  the UK… and this is increasing by 5% per annum.”
• “Overall there appears to be a worryingly large number
  of health problems which could be connected with indoor
  pollution and which affect very large numbers of the
  population.”
• [The Committee recommends that the Government]
  “develop guidelines and codes of practice for indoor air
  quality in buildings which specifically identify exposure
  limits for an extended list of pollutants…”
 Sources of Indoor Air Pollutants
• Building materials
• Furniture
• Furnishings and fabrics
• Glues
• Cleaning products
• Other consumer products
• Combustion appliances (cookers and heaters)
• Open fires
• Tobacco smoking
• Cooking
• House dust mites, bacteria and moulds
• Outdoor air
  Important Indoor Air pollutants
• Nitrogen dioxide
• Carbon monoxide
• Formaldehyde
• Volatile Organic Compounds (VOCs)
• House dust mites (and other allergens, e.g. from pets)
• Environmental tobacco smoke
• Fine particles
• Chlorinated organic compounds (e.g. pesticides)
• Asbestos and man-made mineral fibres
• Radon
            Health Effects
Nitrogen dioxide
• Respiratory irritant
• Elevated risk of respiratory illness in children,
  perhaps resulting from increased susceptibility to
  respiratory infection; inconsistent evidence for
  effects in adults
• Concentrations in kitchens can readily exceed WHO
  and EPA standards
           Health Effects
Carbon monoxide
• An asphyxiant and toxicant
• Hazard of acute intoxication, mostly from
  malfunctioning fuel-burning appliances and
  inadequate or blocked flues
• Possibility of chronic effects of long-term
  exposure to non- lethal concentrations,
  particularly amongst susceptible groups
            Health Effects
Formaldehyde
• Sensory and respiratory irritant and sensitizer
• Possible increased risk of asthma and chronic
  bronchitis in children at higher exposure levels
• Individual differences in sensory and other
  transient responses
• Caution over rising indoor concentrations
            Health Effects
Volatile Organic Compounds (VOCs)
• Occur in complex and variable mixtures
• Main health effects relate to comfort and well-
  being, but benzene (and other VOCs) are
  carcinogenic
• Concern about possible role of VOCs in the
  aetiology of multiple chemical sensitivity; also
  implicated in sick building syndrome
               Health Effects
House dust mites
• House dust mites produce Der p1 allergen, a potent
  sensitizer
• Good evidence of increased risk of sensitization with
  increasing allergen exposure, but this does not necessarily
  lead to asthma
• Small reductions in exposure will not necessarily lead to
  reduced incidence and/or symptoms
• Indoor humidity is important
           Health Effects
Fungi and bacteria
• Dampness and mould-growth linked to self-
  reported respiratory conditions, but little
  convincing evidence for association between
  measured airborne fungi and respiratory
  disease
• Insufficient data to relate exposure to (non-
  pathogenic) bacteria to health effects in the
  indoor environment
             Health Effects
Environmental tobacco smoke (ETS)
•   Sudden infant death syndrome
•   Lower respiratory tract illness
•   Middle ear disease
•   Asthma
12 million children exposed to secondhand
 smoke in homes
           Health Effects
Fine particles
• Consistent evidence that exposure to small
  airborne particles (e.g. PM10) in ambient air
  can impact on human health; mechanisms
  uncertain
• Chronic Obstructive Pulmonary Disease and
  Cardiovascular Disease patients and asthmatics
  probably at extra risk
• Relative importance of indoor sources is
  unknown
            Health Effects
Radon
• Can cause lung cancer
• Estimated that 7,000 to 30,000 Americans die
  each year from radon-induced lung cancer
• Only smoking causes more lung cancer deaths
• Smokers more at risk than non-smokers
   Radon Risk: Non-Smoker
Radon Level If 1000 people who did not smoke were This risk of cancer from
  (pCI/L)     exposed to this level over a lifetime.. radon exposure compares       What to do:
                 About X would get lung cancer                 to …


    20                         8                     Being killed in a violent    Fix your home
                                                              crime
    10                         4                                                 Fix your home

     8                         3                    10x risk of dying in a plane Fix your home
                                                               crash
     4                         2                        Risk of drowning         Fix your home

     2                         <1                    Risk of dying in a home Fix your home
                                                               fire
    1.3                        <1                   Average indoor radon level Fix your home


    0.4                        <1                   Average indoor radon level Fix your home


           If you are a former smoker, your risk may be higher
          Radon Risk: Smoker
Radon Level     If 1000 people who smoke were             This risk of cancer from  What to do:
  (pCI/L)     exposed to this level over a lifetime..    radon exposure compares Stop smoking and
                About X would get lung cancer                       to …                …


    20                         135                        100x risk of drowning       Fix your home


    10                          71                        100x risk of dying in a   Fix your home
                                                                home fire
    8                           57                                                  Fix your home

    4                           29                        100x risk of dying in a   Fix your home
                                                               plane crash
    2                           15                      2x the risk of dying in a car Fix your home
                                                                    crash
    1.3                         9                       Average indoor radon level Fix your home


    0.4                         3                       Average indoor radon level Fix your home


          If you are a former smoker, your risk may be lower
                Radon
• 55% of our exposure to radiation comes
  from radon
• colorless, tasteless, odorless gas
• formed from the decay of uranium
• found in nearly all soils
• levels vary
(From: http://www.epa.gov/iaq/radon/zonemap.html)




                                                    Zone pCi/L
                                                     1    >4
                                                     2   2-4
                                                     3    <2
    Radon: How it Enters Buildings
•   Cracks in solid floors
•   Construction joints
•   Cracks in walls
•   Gaps in suspended floors
•   Gaps around service pipes
•   Cavities inside walls
•   The water supply



                                http://www.epa.gov/iaq/radon/pubs/citguide.html#howdoes
Radon: Reducing the Risks
• Sealing cracks in floors and walls
• Simple systems using pipes and fans
Sick Building Syndrome (SBS)

             vs

Building Related Illness (BRI)
   Sick Building Syndrome
• A persistent set of symptoms in > 20%
  population
• Causes(s) not known or recognizable
• Complaints/Symptoms relieved after exiting
  building
        Complaints/Symptoms
•   Headaches             •   Dry Skin
•   Fatigue               •   Nasal Congestion
•   Reduced Mentation     •   Difficulty Breathing
•   Irritability          •   Nose Bleeds
•   Eye, nose or throat   •   Nausea
    irritation
  Building Related Illness
• Clinically Recognized Disease
• Exposure to indoor air pollutants
• Recognizable Causes
Clinically Recognized Diseases
  –Pontiac Fever – Legionella spp.
  –Legionnaire's Disease
  –Hypersensitivity Pneumonitis
  –Humidifier Fever
  –Asthma
  –Allergy
  –Respiratory Disease
    • Chronic Obstructive Pulmonary Disease
Ventilation
Movement of Air Into / Out of Homes
• Amount of air available to dilute pollutants
  – important indicator of the likely contaminant
    concentration
• Indoor air can mix with outside air by
  three mechanisms
  – infiltration
  – natural ventilation
  – forced ventilation
Movement of Air Into / Out of Homes
• Infiltration
   – natural air exchange that occurs between a building
     and its environment when the doors and windows are
     closed
   – leakage through holes or openings in the building
     envelope
   – pressure induced
      • due to pressure differentials inside and outside of the
        building
      • especially important with cracks and other openings in
        wall
  Movement of Air Into / Out of Homes
• Natural ventilation
  – air exchange that occurs when windows or doors are
    opened to increase air circulation
• Forced ventilation
  – mechanical air handling systems used to induce air
    exchange using fans and blowers
• Trade-offs
  – cut infiltration to decrease heating and cooling costs vs.
    indoor air quality problems
Movement of Air Into / Out of Homes
• Infiltration rates
   – Influenced by
      • how fast wind is blowing, pressure differentials
      • temperature differential between inside and
        outside of house
      • location of leaks in building envelope
Air Pollution Prevention
 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
Absorption
Adsorption
Combustion
Cyclone
Filtration
Electrostatic Precipitator
Liquid Scrubber
                                            Sulfur Dioxide
                                               Control




http://www.apt.lanl.gov/projects/cctc/factsheets/puair/adflugasdemo.html

				
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