Indoor Air Pollution

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					Indoor Air
 Pollution
    Ch 17
           Indoor air pollution
• Indoor air contains higher concentrations of pollutants
  than outdoor air (up to 70x)
   – Synthetic materials not comprehensively tested
   – To reduce heat loss & improve energy efficiency:
      • ventilation systems are sealed off & recirculate air
      • windows do not open
      • This traps pollutants inside.

• Indoor air pollution usually is a greater threat to human
  health than outdoor air pollution.
   – Avg. U.S. citizen spends 90% of time indoors
   – 6,000 people die per day from indoor air pollution

• Pollution levels inside cars in traffic clogged urban
  areas can be up to 18 times higher.
     Indoor Air Pollution--Developing World
• From burning wood, charcoal, dung, crop waste
  – With little to no ventilation
  – Soot and carbon monoxide
  – Causes pneumonia, bronchitis, allergies, cataracts,
    asthma, heart disease, cancer & death
    • ~1.6 million deaths/year
   Indoor Air Pollution--Developed World

• According to the EPA, the 4 most dangerous
  indoor air pollutants in developed countries are:
  – Tobacco smoke
  – Formaldehyde
  – Radioactive radon-222 gas
  – Very small fine & ultrafine particles
• Other Important           • Sources
  Indoor Air pollutants       – Building materials
  – Nitrogen dioxide          – Furnishings & fabrics
  – Carbon monoxide           – Glues
                              – Cleaning products
  – Volatile Organic
    Compounds (VOCs)          – Combustion
                                appliances (cooking &
  – House dust mites (&         heating)
    other allergens… from     – Open fires
    pets)
                              – Smoking
  – Chlorinated organic       – Living organisms
    compounds (ex.
                              – Outdoor air
    pesticides)
  – Asbestos & man-
    made mineral fibers
             Tobacco Smoke
• The most dangerous indoor pollutants in
  the developed world
  – Secondhand smoke from cigarettes is
    especially dangerous
    • Containing over 4000 dangerous chemicals
    • Causes eye, nose, and throat irritation
    • Smoking has declined in developed nations
    Volatile Organic Compounds (VOCs)
• The most diverse group of indoor air pollutants
  – Released by everything from plastics and oils to
    perfumes and paints
     • Ex. formaldehyde, which leaks from pressed wood and
       insulation, irritates mucous membranes and induces skin
       allergies
     • Ex. pesticides, which are found indoors more often than
       outdoors due to seepage


• Most VOCs are released in very small amounts
  – Unclear health effects due to low concentrations
                        Radon-222
• colorless, tasteless, odorless, radioactive gas from
  decay of U-238 found in some soils & rocks
• can seep into some houses
   – Most homes are now radon resistant

• 55% of our exposure to radiation comes from radon
   – May harm lungs from long term exposure.
      • increases the risk of lung cancer
          – Chance increase more if a smoker (synergistic effect)
   – causes 20,000 deaths a year in the U.S.
• Reducing the risk
   – Sealing cracks in floors and walls
   – Simple systems using pipes and fans
Sources & paths of entry for indoor radon-222 gas
Radon risk across the U.S.
    Living organisms can pollute indoors
• Dust mites
  – feed on human skin & dust
     • live in materials such as bedding & furniture fabrics
  – can cause asthma attacks & allergic reactions

• Fungi, mold, mildew, airborne bacteria
  – cause severe allergies, asthma,
    & other respiratory ailments

• Animal dander
  – worsen asthma
             Major Indoor Pollutants
  Pollutant                              Source         Health Effects
1, 1, 1-                        Aerosol sprays       Dizziness, breathing
Trichloroethane                                      irregularities
Asbestos                        Pipe insulation,     Lung Cancer and
                                ceilings, floor      asbestosis
                                tiles, oven mitts
Benzo-a-pyrene Tobacco smoke,                        Lung Cancer
               woodstoves
Carbon                          Faulty furnaces,     Headache, heartbeat
Monoxide                        cigarette smoke      irregularities, death,
                                                     CO has 250x affinity
                                                     for hemoglobin than O2

       http://www.metricmind.com/ac_honda/main.htm
Chloroform                        Pulp and paper mills, Cancer
                                  water and
                                  wastewater plants
Formaldehyde                      Paneling, particle     Nausea, dizziness,
                                  board, furniture,      irritation of throat,
                                  carpeting, adhesives   eyes, and lungs
Methylene                         Paint strippers and    Nerve disorders,
chloride                          thinner – persistent   diabetes
Nitrogen oxides Furnaces, stoves,                        Headaches, irritated
                fireplaces and vents                     lungs
Para-           Air fresheners,                          Cancer
dichlorobenzene mothballs


       http://www.metricmind.com/ac_honda/main.htm
Radon – 222                   Soil and rock near     Lung cancer
                              house foundation,
                              concrete
Styrene                       Carpets, plastics,     Kidney & liver
                                                     damage
Tetrachlor-                   Dry-cleaning fluid     Nerve disorders,
 ethylene                                            damage to liver and
                                                     kidneys, cancer
Tobacco                       Cigarettes and other   Lung cancer and
Smoke                         smoking sources        heart disease
Organic          Dust mites, fungal and              Allergies, coughs,
Material (Living algal spores, dust                  sneezing, eye
Organisms)       (human skin), animal                irritation, sore
                 dander, hair, carpet                throats, difficulty
                 fibers, fur                         breathing
      http://www.metricmind.com/ac_honda/main.htm
         Sick Building Syndrome
• A sickness produced by indoor pollution w/
  general & nonspecific symptoms
  – Ex. dizziness, headaches, coughing, sneezing,
    nausea, burning eyes, chronic fatigue, irritability,
    eye/nose/throat irritation, dry skin, nasal congestion,
    difficulty breathing, nose bleeds, flu-like symptoms
     • persistent set of symptoms in >20% population
     • complaints/Symptoms relieved after exiting building
     • causes(s) not known or recognizable

• New buildings are more commonly “sick” than
  old ones because of reduced air exchange.
  – Can be solved with low-toxicity building materials &
    good ventilation
          Building Related Illness
• Also due to exposure to indoor air pollutants
• Recognizable Causes
• Clinically Recognized Disease
  –Examples
     •   Pontiac Fever – Legionella spp.
     •   Legionnaire's Disease
     •   Hypersensitivity Pneumonitis
     •   Humidifier Fever
     •   Asthma
     •   Allergy
     •   Respiratory Disease
          – Chronic Obstructive Pulmonary Disease
    Reducing Indoor Air Pollution

•Little effort has been devoted to reducing indoor
air pollution even though it is more harmful to
human health than outdoor air pollution

•Environmental & health scientists call for us to
focus on preventing air pollution (especially
indoor) in developing countries.
                                      Solutions
                                  Indoor Air Pollution
                       Prevention                 Cleanup or
                                                  Dilution

Cover ceiling tiles & lining of AC                Use adjustable fresh air
ducts to prevent release of mineral               vents for work spaces
fibers
                                                  Increase intake of outside air
Ban smoking or limit it to well
ventilated areas
                                                  Change air more frequently
Set stricter formaldehyde
emissions standards for carpet,                   Circulate a building’s air
furniture, and building materials                 through rooftop green houses

Prevent radon infiltration                        Use exhaust hoods for stoves
                                                  and appliances burning
Use office machines in well                       natural gas
ventilated areas
Use less polluting substitutes for                Install efficient chimneys for
harmful cleaning agents, paints,                  wood-burning stoves
and other products
                                                                         Fig. 19-20, p. 461
 We can reduce indoor air pollution
• In developed countries:
  – Use low-toxicity material
  – Monitor air quality
  – Keep rooms clean
  – Limit exposure to chemicals
  – Allow for better mixing of indoor & outdoor air

• In developing countries:
  – Dry wood before burning
  – Cook outside
  – Use less-polluting fuels (natural gas)
 We can reduce indoor air pollution
• The amount of air available (for mixing of indoor
  & outdoor air) to dilute pollutants is an important
  indicator of the likely contaminant concentration
  – Indoor air can mix with outside air by 3 mechanisms
     • infiltration
     • natural ventilation
     • forced ventilation
     Mixing of Indoor & Outdoor Air
• Infiltration
  – natural air exchange that occurs between a
    building & its environment when doors &
    windows are closed
     • leakage through holes or openings in the building
        – Influenced by:
            » pressure differentials inside & outside the building
            » temperature differentials inside & outside of bldg
                 ~in winter, warm air inside wants to rise  exits
                  through cracks in ceiling & draws in outside air
            » how fast wind is blowing
    Mixing of Indoor & Outdoor Air
• 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 & blowers
                         What Can You Do?
                        Indoor Air Pollution

• Test for radon and formaldehyde inside your home and take
  corrective measures as needed.
• Do not buy furniture and other products containing formaldehyde.
• Remove your shoes before entering your house to reduce inputs
  of dust, lead, and pesticides.
• Test your house or workplace for asbestos fiber levels and for
  any crumbling asbestos materials if it was built before 1980.
• Don't live in a pre-1980 house without having its indoor air
  tested for asbestos and lead.
• Do not store gasoline, solvents, or other volatile hazardous
  chemicals inside a home or attached garage.
• If you smoke, do it outside or in a closed room vented to the outside.
• Make sure that wood-burning stoves, fireplaces, and kerosene-
  and gas-burning heaters are properly installed, vented, and
  maintained.
• Install carbon monoxide detectors in all sleeping areas.
                                                                 Fig. 19-21, p. 461

				
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