1. Indoor Air Pollution
Ch 17

2. 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.

3. 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

4. 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

5. Other Important Indoor Air pollutants Sources
Nitrogen dioxide
Carbon monoxide
Volatile Organic Compounds (VOCs)
House dust mites (& other allergens… from pets)
Chlorinated organic compounds (ex. pesticides)
Asbestos & man-made mineral fibers
Sources
Building materials
Furnishings & fabrics
Glues
Cleaning products
Combustion appliances (cooking & heating)
Open fires
Smoking
Living organisms
Outdoor air

6. 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

7. 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

8. 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

9. Sources & paths of entry for indoor radon-222 gas

10. Radon risk across the U.S.

11. 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

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

14. Pulp and paper mills, water and wastewater plants Cancer
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
Para-dichlorobenzene
Air fresheners, mothballs

15. Soil and rock near house foundation, concrete Lung cancer
Radon – 222
Soil and rock near house foundation, concrete
Lung cancer
Styrene
Carpets, plastics,
Kidney & liver damage
Tetrachlor-
ethylene
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 (Living Organisms)
Dust mites, fungal and algal spores, dust (human skin), animal dander, hair, carpet fibers, fur
Allergies, coughs, sneezing, eye irritation, sore throats, difficulty breathing

16. 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

17. 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

18. 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.

19. Use adjustable fresh air vents for work spaces
Solutions
Indoor Air Pollution
Prevention
Cleanup or Dilution
Cover ceiling tiles & lining of AC ducts to prevent release of mineral fibers
Use adjustable fresh air vents for work spaces
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, furniture, and building materials
Circulate a building’s air through rooftop green houses
Figure 19.20
Solutions: ways to prevent and reduce indoor air pollution. QUESTION: Which two of these solutions do you think are the most important?
Prevent radon infiltration
Use exhaust hoods for stoves and appliances burning natural gas
Use office machines in well ventilated areas
Use less polluting substitutes for harmful cleaning agents, paints, and other products
Install efficient chimneys for wood-burning stoves
Fig , p. 461

20. 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)

21. 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

22. 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

23. 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

24. • Do not buy furniture and other products containing formaldehyde.
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.
Figure 19.21
Individuals matter: ways to reduce your exposure to indoor air pollution. QUESTION: Which three of these actions do you think are the most important?
• 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 , p. 461