1. Indoor Air Pollution
Chapter 12, Sections 5 & 6: Types, Sources, & Effects

2. Objective Starting new unit: Risk & Toxicology
Identify types and sources of indoor air pollution.
Explain how indoor air pollutants affect human health.
Describe ways to reduce indoor air pollution.
Read the passage…

3. Why is indoor air quality important?
Levels of common pollutants are generally higher indoors
70 to 90% of time spent indoors
home, work, school, cars
Many significant pollution sources in the home
gas cookers, paints, glues
Personal exposure to many common pollutants is driven by indoor exposure... May lead to cancer & other ailments.
Especially important for susceptible groups:
sick, old, very young, pregnant women, smokers, people with respiratory/heart problems, factory workers
Typically 2-5X higher levels of pollutants indoors vs. outdoors
particulate matter, even pesticides (from being tracked indoors, then nowhere to disperse once trapped in the home)
inside your car, pollution levels can be up to 18X higher than outside (esp. in high traffic areas)

4. Exposure
Time spent in various environments in US and less- developed countries:

5. Respiratory System Defense: Broken down by smoking, causing Nose hairs
Mucus
Sneezing/coughing
Cilia (line upper respiratory tract)
Broken down by smoking, causing
Lung cancer
Asthma
Chronic bronchitis
Emphysema
Cilia trap pollutants and expel to throat (where you swallow or cough up)

6. Humans Die from Pollution
Annually, U.S. estimates 65, ,000 premature deaths from outdoor pollution
Indoor pollution included: 150, ,000 premature deaths
Worldwide: 2.7 million premature deaths
Millions more face illness
350,000 deaths annually from air pollution = 1-2 fully loaded jumbo jets crashing each day with no survivors

7. 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…”

8. Top Dangerous Pollutants
According to the EPA, 3 most dangerous indoor air pollutants:
Cigarette smoke
Formaldehyde (colorless, extremely irritating gas; used to manufacture many household materials)
Radioactive Radon-222 Gas
Additionally:
Asbestos
Burning candles indoors
Tiny fibers of fiberglass (potentially potent carcinogen)

9. Sources of Indoor Air Pollutants
Building materials
Furniture
Furnishings and fabrics
Glues
Cleaning products
Combustion appliances (cookers and heaters)
Other consumer products
Open fires
Tobacco smoking
Cooking
House dust mites, bacteria and moulds
Outdoor air

10. Sick Building Syndrome
A persistent set of symptoms in >20% population
Headaches
Fatigue
Reduced Mentation
Irritability
Eye/nose/throat irritation
Cause(s) not known or recognizable
Complaints/Symptoms relieved after exiting building
Dry Skin
Nasal Congestion
Difficulty Breathing
Nose Bleeds
Nausea
Other ailments: dizziness, headaches, coughing, sneezing, nausea, burning eyes, chronic fatigue, flulike symptoms, “sick building syndrome”

11. Building Related Illness
Clinically recognized disease (different from “sick building”)
Exposure to indoor air pollutants
Recognizable Causes
Pontiac Fever – Legionella spp.
Legionnaire's Disease
Hypersensitivity Pneumonitis
Humidifier Fever
Asthma
Allergy
Respiratory Disease
Chronic Obstructive Pulmonary Disease

12. Health Effects

13. Important Indoor Air pollutants
Nitrogen dioxide
Carbon monoxide
Formaldehyde
Asbestos
Volatile Organic Compounds (VOCs)
House dust mites (and other allergens, e.g. from pets)
Environmental tobacco smoke
Fine particles
Radon
Chlorinated organic compounds (e.g. pesticides)
Asbestos and man-made mineral fibres

14. Nitrogen dioxide (criteria pollutant)
Health Effects
Nitrogen dioxide (criteria pollutant)
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

15. Carbon monoxide (criteria pollutant)
Health Effects
Carbon monoxide (criteria pollutant)
An asphyxiant and toxicant
Impairs perception, slows reflexes, headaches, drowsiness
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
Reacts with hemoglobin in red blood cells and reduces the ability of blood to bring oxygen to body cells
This is what kills you if you leave your engine running in a closed garage

16. 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
May cause: chronic breathing problems, dizziness, rash, headaches, sore throat, sinus and eye irritation, wheezing, nausea
Sources: building materials (plywood, particle board, paneling), furniture, drapes, upholstery, adhesives (in carpeting/wallpaper), urethane (insulation), fingernail hardener (think about the strong odors from Mrs. Flatford’s room), wrinkle-free coating on permanent-press clothing
“manufactured homes” (trailers)- 1/5,000 who live in trailers for 10+ years will develop cancer from prolonged formaldehyde exposure

17. Asbestos

18. Volatile Organic Compounds (VOCs)
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
Etiology = cause

19. 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
Der p1 is an active digestive enzyme that can cause cell death in the lungs by ‘melting’ the glue like substance that binds cells together. The cell’s death in turn gives Der p1 access to the body and blood stream. 

20. 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

21. Environmental tobacco smoke (ETS)
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

22. Fine particles (criteria pollutant)
Health Effects
Fine particles (criteria pollutant)
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

23. Airborne Particulates Examination
Take a particulate strip home to place next to your bed.
Compare with school in 3 days.
With your group of 3:
Choose an area in the school
Label your particulate strip
Place your particulate strip
Take a picture of your filled out, placed particulate strip
Partner Roles:
Scribe
Installer
Photographer

24. Predict!
Which location in the school do you think will have the poorest air quality?
Do you think the particulate strip next to your bed will be the same, better, or worse?

25. Health Effects Radon Naturally formed from the decay of uranium
55% of our exposure to radiation comes from radon
Colorless, tasteless, odorless gas
Found in nearly all soils
(levels vary)
Seeps upward through
soil and quickly disperses
to harmless levels outdoors
BUT, indoors…

26. 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
Builds up indoors, especially in lower levels of structures, particularly where ventilation is poor
Can cause lung cancer
Estimated that 7,000 to 30,000 Americans die each year from radon-induced lung cancer
Uranium miners…
Only smoking causes more lung cancer deaths
Risk level affected by: how much radon is in your home, how much time you spend in your home, and if you smoke

27. Radon Risk: Non-Smoker
Radon Level
(pCI/L)
If 1000 people who did not smoke were exposed to this level over a lifetime.. About X would get lung cancer
This risk of cancer from radon exposure compares to …
What to do: 20 8
Being killed in a violent crime
Fix your home 10 4 3
10x risk of dying in a plane crash 2
Risk of drowning
<1
Risk of dying in a home fire
1.3
Average indoor radon level .4
If you are a former smoker, your risk may be higher

28. Radon Risk: Smoker If you are a former smoker, your risk may be lower
Radon Level
(pCI/L)
If 1000 people who smoke were exposed to this level over a lifetime.. About X would get lung cancer
This risk of cancer from radon exposure compares to …
What to do:
Stop smoking and … 20
135
100x risk of drowning
Fix your home 10 71
100x risk of dying in a home fire 8 57 4 29
100x risk of dying in a plane crash 2 15
2x the risk of dying in a car crash
1.3 9
Average indoor radon level .4 3
If you are a former smoker, your risk may be lower

29. Radon: Reducing the Risks
Sealing cracks in floors and walls
Simple systems using pipes and fans
Test indoor air & compare with EPA’s acceptable levels
More information
Such systems are called "sub-slab depressurization," and do not require major changes to your home. These systems remove radon gas from below the concrete floor and the foundation before it can enter the home. Similar systems can also be installed in houses with crawl spaces.

30. Reducing Indoor Air Pollution

31. Reducing Indoor Air Pollutants
Using simple stoves that burn more efficiently (reduces deforestation)
Using simple solar cookers
Breathing wall
Absorbs indoor dirty air
Exhales clean air
Improve ventilation

32. 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

33. Ventilation Infiltration Temperature induced (stack effect)
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
pressure induced
Due to pressure differentials inside and outside of the building
Especially important with cracks and other openings in wall
Temperature induced (stack effect)
driven by air movement through holes in floors, ceilings
in winter, warm air in a building wants to rise, exits through cracks in ceiling and draws in

34. Ventilation Natural ventilation Forced ventilation Trade-offs
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

36. What pollutants cause these problems?
Suspended particulate matter: asthma
Fine particles
Ultrafine particles
Sulfur dioxide: asthma/ bronchitis
Nitrogen oxides: asthma/ bronchitis
Volatile organic compounds: cancer