This document discusses indoor air quality (IAQ) and common indoor air pollutants. It notes that sick building syndrome is associated with indoor air pollution and its symptoms. It provides steps to control IAQ such as eliminating sources of pollution, controlling humidity, and ensuring proper ventilation. Common indoor pollutants discussed include radon, volatile organic compounds (VOCs), allergens, and carbon monoxide. The document also discusses tight homes, radon testing and mitigation, carbon monoxide dangers, off-gassing of chemicals from products, and high priority chemicals to avoid like PVC and formaldehyde.

1. 1
Indoor Air Quality (IAQ)
dust mite

2. Sick Building Syndrome
• Sick Building Syndrome - associated with
indoor air pollution. Symptoms include
headaches, sinus congestions, dizziness, itchy
and watery eyes, nausea, lethargy, and a
reduced capacity to concentrate.
• EPA studies reveal that levels of indoor air
pollutants may be 2 to 5 times, and occasionally
more than 100 times, higher than outdoor
levels.
• Most people spend over 90% of their time
indoors.
2

3. 3
Steps in Controlling IAQ
• Eliminate the Source
– Choose non-polluting products
• Control the Source
– Isolate the source (such as radon and CO)
– Seal or enclose the source (such as asbestos)
– Control relative humidity
• Ventilation
• Air Cleaning and Filtration
• Or as John Bower (Author of the Healthy Home
Book) says, “Eliminate Separate Ventilate”

4. 4
Indoor Air Quality and RH
Total Water Vapor Air Can Hold

5. 5
Common IAQ Pollutants
• Radon
• Volatile Organic Compounds (VOCs)
• Dust and Dust Mites
• Allergens
• Carbon Monoxide
• Mold and Mildew
• Household Chemicals

6. 6
Tight Homes
Keep out:
• Pollen and dust
• Noise
• Crawl space molds and moisture
• Insulation particles
• Termiticides and other soil treatments
• Radon
• Humid air in summer/dry air in winter

7. 7
Radon
• Radioactive gas formed by decay of uranium
in the soil
• Any type of home (leaky or sealed) may have
a radon problem
• 14,000 deaths per year in the United States;
could range from 7,000 to 30,000 deaths per
year
• More risky for smokers (synergistic effect)

8. 8
EPA Map of Radon Zones
Zone 1 Highest Potential:
predicted average indoor
radon screening level
greater than 4 pCi/L
Zone 2 Moderate
Potential: radon screening
level between 2 and 4 pCi/L
Zone 3 Low Potential:
radon screening level less
than 2 pCi/L
pCi/L = picocuries per liter (4
pCi/L is the EPA maximum indoor
guideline)

9. 9
EPA Maps of Radon Zones

10. 10
Radon
• Maximum accepted level by EPA is 4 picocuries/liter
• Testing kits are widely available
• Resources
• www.radon.com
• National Environmental Health Association's
(NEHA) National Radon Proficiency Program
(NRPP) www.neha-nrpp.org
• National Radon Safety Board (NRSB) -
www.nrsb.org

11. • Use state or national-certified kits
• Test radon levels in lowest habitable rooms
• Follow directions on kit carefully
• For levels near 4 picocuries/liter, get professional testing
• If levels are well over 4 picocuries/liter, ventilate home
and consider relocation during remediation
11
Radon Testing

12. 12
Radon Sub-slab Mitigation
A. Permeable gravel layer
B. Plastic
C. Seal air infiltration
D. Vent stack (labeled)
E. Junction boxes for
continuous fan
Test after occupancy;
install blower if needed

13. 13
Sub-slab Radon Pipe
• 4” PVC – label it!
• Connect to horizontal run of perforated
pipe under slab
• Extend through roof

14. 14
Radon Mitigation Blowers
• Test for radon after
occupancy
• If levels exceed 4
picocuries per liter,
install continuous
blower

15. 15
Radon Mitigation with Blower
• Basement location – pipe
must be well sealed to roof
• Blue alcohol manometer
indicates if blower is working

16. Carbon Monoxide
• A colorless, odorless, poisonous gas that results from
incomplete combustion of fuels
• Household sources: furnaces, gas heaters, motor
vehicles
• Most signs and symptoms of CO exposure are
nonspecific (headache or nausea); can be mistaken as
viral illnesses
• Undetected or unsuspected CO exposure can result in
death
16

17. 17
• Eliminate combustion appliances, especially vent-less
systems
• Use only direct vent isolated air combustion
appliances
• Use carbon monoxide monitor and alarm
• Test each combustion appliance (gas water heater,
gas furnace, gas range and oven, gas space heater)
Carbon Monoxide

18. 18
Health Effects of CO Levels
Maximum level ASHRAE recommends in an occupied
building is 9 parts per million (ppm)
CO Level (ppm) Symptom
100 Nothing proven
200 Headache, tiredness, dizziness
400 Headaches, life threatening after three
hours
800 Convulsions within 45 minutes, death
within 2-3 hours
1,600 Death within one hour
3,200 Death within one-half hour

19. Chemical Off-gassing and
Multiple Chemical Sensitivity

20. What is Off-gassing?
The event of emission of chemicals into the air
when wet and the continued emission of
chemicals into the air after a product is “dry”.
• Off-gassing is often odorless
– The level of off-gassing may be below the typical
human ability to detect
– Some chemicals are odorless (CO)

21. “Everyday” Chemicals
• World Health Organization says that some 100,000
chemicals are now on the market and 1,000 to 2,000
are added each year.
• Consumers are exposed to 60,000 to 70,000 different
chemicals each year.
• Only some chemicals are tested for their effect on
humans.
• NIOSH has only tested 576 out of 100,000.

22. What Produces Off-gas?
• Treated wood: arsenic, formaldehyde, aliphatic
hydrocarbons
• Insulating materials: vinyl chloride, formaldehyde
• Plastic piping: formaldehyde, vinyl chloride
• Vinyl or plastic interior coverings: ketones, esters, ethers
• Wood stains: hexane, heptanes
• Liquid floor wax: formaldehyde
• Carpets: a “soup of chemicals”

23. Impacts of Other Chemicals
• MSG (food additive): retinal deterioration
• Solvents: panic disorder
• Formaldehyde: chronic fatigue
• Pesticides: inability to concentrate, irritability,
depression, poor memory, schizophrenia
• Benzene(gas): leukemia, deteriorating IQ
• Chlorine and ammonia cleaners mixed
together: phosgene gas
23

24. Multiple Chemical Sensitivity
Became more widely know in 1970s after off-gassing from
urea foam formaldehyde insulation in homes.
What is known:
1) Chemical sensitivity can produce any symptom, in
any person, at any time, but the brain and central
nervous system are the most common targets
2) Vast range of individual susceptibility
3) Spreading phenomenon

25. 25
Volatile Organic Compounds (VOC)
• Organic compounds (contain carbon and hydrogen)
that vaporize (become a gas) at room temperature
• Examples: adhesives, manufactured woods that
release formaldehyde, carpet, cleaning products
• Seal cabinets to prevent off-gassing
• In laminated wood, prefer exterior glues to interior
glues
• Can cause eye, nose, and throat irritations and some
types can cause cancer

26. 26
VOC Examples
• Rhinitis (nasal membrane inflammation): laser printers,
diesel exhaust
• Headaches, panic attacks, and kidney problems: solvents
• Heart arrhythmias: aerosol propellants
• Balance and memory difficulties connected to
formaldehyde exposure; asthma to carbonless copy
paper, perfume, and tobacco smoke; and connective
tissue diseases to some fuels, vinyl chloride, and hair dye

27. 27
Formaldehyde Impacts
• Formula  CH2O
• Irritation of eyes nose and throat
• Respiratory problems, lungs
• Menstrual disorders and
pregnancy problems
• Cancer (long term exposure)

28. 28
Household Chemicals
• Cleaning products, degreasers,
solvents, paints and finishes
• Most made of petrochemicals
• Vapor is sometimes toxic
• Very dangerous if swallowed
• Keep locked up away from children

29. What can we do about it?
• Use natural building methods and materials
• Use organic cleaners or steam cleaners for
home and office
• Increase other people’s knowledge
• Look for products labeled (and certified) as
“no VOC or low VOC”

30. Paint and Sealant Options
• “Natural” paints and finishes made from
ingredients such as water, plant oils and
resins, plant dyes and essential oils, clay,
chalk, talcum, milk casein, natural latex, bees'
wax, earth and mineral dyes
• Low VOC
• Zero or No VOC
30

31. Low VOC Finishes
Low VOC paints, stains and varnishes use water as
a carrier instead of petroleum-based solvents.
• They have no, or very low levels of heavy
metals and formaldehyde. Lead – Mercury- Titanium
• To meet EPA standards:
– Paints and stains must not contain over 200 grams
of VOC per liter.
– Varnishes must not contain over 300 grams per liter
31

32. Low VOC Finishes
• As a general rule, low VOC paints, marketed
by reputable paint manufacturers, usually
meet a 50 g/L VOC threshold.
• Paints with the Green Seal Standard (GS-11)
mark are certified lower than 50 g/L (for flat
sheen) or 150 g/L (for non-flat sheen).
• Adding a color tint usually brings the VOC
level up to 10 grams/liter, still quite low.
32

33. 33
Issues with Carpeting
• Regular carpet ingredients
– dyes
– pesticides
– biocides
– chemicals
– odors

34. 34
Chemicals in Carpeting
• Ethylbenzene - eye irritation
• Acetonitrile - respiratory discomfort
• Toluene - cough
• Benzene - dizziness
• Azulene - headaches

35. 35
More Chemicals
• Indene - rash, itching
• Oxarium - muscular
aches
• Styrene - unusual
depression
• Tetradecene
-respiratory tract
irritation
• Dimethyl - sexual
dysfunction
• Methylnaphthalene -
hair loss, weight loss
or gain
• Polyacrylates -
abdominal pain

36. 36
Health Problems
• Neurological and nervous system problems
• Respiratory problems – runny nose/eyes
• Depression - head aches
Sources
• Carpet adhesive - seam sealants
• Synthetic foam - latex - carpet dye

37. High Priority "worst in class" Chemicals
Persistent Bioaccumalitive Toxics (PBTs): pvc,
paints, finishes, etc.
Persistent Organic Pollutants (POPs): subset of
PBTs
– Dioxins, furans and PCBs are the prime POPs connected
with building materials.
Volatile Organic Compounds (VOCs):
formaldehyde
37

38. High Priority "worst in class" Chemicals cont.
1) Chlorinated building materials:
Polyvinyl chloride (PVC) often referred to as “vinyl"
• pipes and conduit
• water proofing
• siding
• roof membranes
• door and window frames
• resilient flooring
• carpet backing
• wall covering
• signage
• window treatments
• furniture
• wire
• cable sheathing
38

39. High Priority "worst in class" Chemicals cont.
39
Chlorinated polyethylene (CPE)
• Geomembranes
• wire and cable jacketing
Chlorinated polyvinyl chloride (CPVC)
• water pipes
Chlorosulfonated polyethylene (CSPE)
• roof membranes
• electrical connectors
• sheet membrane for pond liners
Polychloroprene (CR or chloroprene rubber, also brand name Neoprene)
• Geomembranes
• weather stripping
• expansion joint filler
• water seals
• other gaskets and adhesives

40. High Priority "worst in class" Chemicals cont.
2) PBT based material treatments
– Brominated Flame Retardants (BFRs), particularly
PBDE (polybrominated diphenyl ether)
• Furniture foam and fabrics
– Perfluorochemicals (PFCs) (most notably PFOA)
• Furniture & dividers - stain and non-stick
treatments, including Scotchguard®, Teflon®,
Stainmaster®, Scotchban®, and Zonyl®
40

41. High Priority "worst in class" Chemicals cont.
3) Heavy metal additives and components. Heavy
metals are inherently persistent and often bio-
accumulative, including:
Mercury
• thermostats
• thermometers
• switches
• fluorescent lamps
41

42. High Priority "worst in class" Chemicals cont.
42
Lead
• flashing
• terne, copper and other roof products
• solder
• wire insulation jacketing (most PVC wiring
but apparently you can now buy even PVC
wire without lead)
Cadmium
• Paint (use GreenSeal paints to avoid)
• Some PVC products (as a stabilizer)

43. 43
• Untreated chemical-free wool carpets
– no pesticides
– no dyes
– no biocides
• Green Label carpeting
– Carpet and Rug Institute program
• Green Label Plus carpeting
What Alternatives are Available?

44. Green Label Carpeting
• Carpets are tested by an independent, certified
laboratory and meet stringent criteria for low chemical
emissions.
• Green Label Plus is designed for architects, builders,
specifiers and facility managers who want assurances
that carpet and adhesive products meet the most
stringent criteria for low chemical emissions.
• Green Label Plus represents the fourth time the carpet
industry has voluntarily enhanced the IAQ standard for
its products.
http://www.carpet-rug.org/commercial-customers/green-building-and-the-environment/green-label-plus/index.cfm
44

45. Available Alternatives
Criteria for GreenSure Designation (Sherwin-Williams)
• Products that offer maximum performance and long-term
durability
• Have the highest indoor air quality ratings for low VOC and
low odor
• Meet or exceed the GS-11 criteria for coatings used in LEED-
certified buildings (LEED certification means that certain
"green building" standards are met, such as energy efficiency
and indoor environmental quality)
45

46. Third Party Verification Organizations
46

47. Green Building Material Resources
47

48. Green Building Material Resources
48

49. 49
Fungi
• Molds, yeasts and mushrooms
• 100,000 species
• 25% of earth’s biomass
• Reproduce via spores
• Digest organic material
• Old building issue: rot
• New building issue: sick
building

50. 50
Dust, Dust Mites, and Allergens
Avoid Source
– Air leaks bring in dust (and dust mites)
and allergens
– Pets increase dust levels in homes
– Wall-to-wall carpeting is perfect
environment for dust mites
Control Source
– Frequent vacuuming helps;
central vacuums exhaust dust outside
– Japanese homes use controlled entry or dust removal zone
(take off shoes, put on slippers)
– HVAC filtration systems

51. 51
Dust, Dust Mites, Allergens
Treatment of Source
• Vacuum frequently
• Control moisture
• Control air filtration
• Electrostatic precipitator as a filter
• Eucalyptus oil

52. 52
Building Mold
Two types
of outbreaks
– spot problem
– systemic
problem
• Is this a
spot problem
or systemic?
• What caused it?

53. 53
• CDC study: 75% increase in reported
asthma cases from 1980 to 1994
• Cleveland study linked toxic mold to infant
pulmonary hemorrhaging cases
• Mold is often a leading suspect in “sick
building” syndrome
• Media attention and law suits
Mold Issue: Driving Forces

54. 54
If mold spreads in a house,
“It must be torn down, its stones, timbers, and all
plaster - and taken out of town to an unclean
place.”
Leviticus 14:45
Mold = New Issue: Old Problem

55. 55
• Building decay… 100% RH
• Interior mold…… RH >70%
• Dust mites……… RH >50%
• Static electricity… RH <25%
Relative Humidity Levels

56. 56
Mold Remediation = Serious Business

57. 57
Potential Health Effects
• Allergic reactions: allergies and asthma
• Infections
• Irritant: eye, skin, respiratory tract
• Toxic molds (mycotoxins)

58. 58
Conditions for Mold Growth
• Food: organic materials
– Cellulose building materials (wood, paper faced
sheetrock)
• Temperature: 59°F to 122° F
• Excess moisture - the primary cause
– Water: flooding, roof and plumbing leaks
– Water vapor: mold grows above 70% RH

59. 59
• Crawl spaces and basements
• Attics
• Inside damp/wet walls and on siding
• Carpets on concrete slabs
• Windows
• Bathrooms
• Behind vinyl wall coverings
• Ductwork
Locations for Mold Formation

60. 60
Mold Formation after Flood

61. 61
Poor Flashing = Mold Formation

62. 62
Mold under Vinyl Wallpaper

63. 63
Mildew Formation
Mildew Growth

64. Mold
Mold Growth

65. 65
Build to Prevent Mold
Control Moisture
• Traditional methods: overhangs, gutters flashings, caulking,
drainage
• Air-sealed floors, walls and ceilings
• Simplified roof geometry
• Masonry capillary breaks
• Complete foundation moisture barrier; closed crawl spaces
• Dry out building materials before installing vapor barriers,
sheetrock, carpet

66. 66
Build to Prevent Mold (cont.)
• Consider installing multiple foundation
drains – make sure they drain completely
away from home
• Relative humidity should be 30% to 50%
• Design cooling system for “latent load”
making sure cooling system dehumidifies
properly

67. 67
Fixing Mold Problems
• Find the moisture source and fix the problem FAST
• Remove mold FAST
• Protect workers and occupants: respirators,
eye and hand protection, exhaust work areas
• Clean with soap and water, then chlorine bleach,
which should remain in place for several hours
• Final cleaning to remove dead mold spores
Mold sampling is best used
for litigation and research

68. 68
Beware: Mold Lawyers
• www.toxic-mold-news.com
• www.toxicmoldinfocenter.com
• www.toxicmold-attorneys.com
• www.toxic-mold-stachybotrys.com
• www.atoxicmoldattorneyforyou.com
• www.moldlawyer.com
• www.nationaltoxicmoldattorneys.com

69. 69
• Uncontrolled natural ventilation (air leaks)
• Controlled mechanical ventilation
• Heat recovery ventilation (HRV)
– without moisture removal
– with moisture removal (Enthalpy Recovery
Ventilation - ERV)
Ventilation Options

70. 70
Ventilation Make-Up Air
• Incoming air leakage
• Independent air inlet vents
• Air inlet to HVAC return duct

71. 71
Ventilation
• Why ventilate?
– Humidity control
• Reduce excessive moisture harmful to the building structure
• Reduce excessive moisture that is a source of mold and mildew
growth
– Help prevent pressure imbalances
– Dilute odors and pollutants harmful to human health
– Provide oxygen for fuel combustion
• Not a solution to high levels of indoor pollutants

72. 72
Ventilation
• Ventilation required by code (IRC Section R303)
– Natural ventilation using windows, or
– Mechanical ventilation meeting ASHRAE 62
– Bathrooms
• Operable windows or 50 cfm/intermittent or 20 cfm continuous

73. 73
ASHRAE 62
• American Society of Heating, Refrigeration, and Air
Conditioning Engineers (ASHRAE) sets standards for the
heating, cooling and refrigeration industry
• ASHRAE 62 states: a home must have the following
ventilation rate in cubic feet per minute:
(7.5 cfm x number of people) + (0.01 x house area in square feet)
Number of people = number of bedrooms + 1

74. 74
ASHRAE 62 Example
2,400 square foot home with 4 bedrooms
• Number of occupants = 4 bedrooms + 1 = 5 persons
Minimum ventilation rate =
 (7.5 cfm/person x 5 persons) + (0.01 x 2,400 sq ft) =
 (37.5 cfm) + 24 = 61.5 cfm

75. 75
Spot Ventilation
• Bathroom fans
• Range hoods
• Choose low sone fans
rated for continuous use
• Example – Panasonic
“WhisperGreen” allows
homeowner to set
ventilation rate

76. 76
Installation is Critical
• Poor product
(vinyl duct)
• Potential for
condensation on
soffit board
• Exhaust air will
humidify attic

77. 77
Simple Ventilation System
• Two approaches
– Low sone (db)
exhaust fans
– Central HVAC
blower
In the diagram, only
new feature is
dampered fresh air
to outside

78. 78
-
-
Low sone bath
exhaust fan
with 50 cfm
at 0.3” static
P
Low sone kitchen
exhaust fan with
100 cfm at 0.3”
static P
Source of
fresh air
Dampered
inlet duct
Exhaust Fan Ventilation

79. 79
Ventilation Using HVAC Blower

80. 80
Make-up Air via Air Handler
When the air
handler runs,
assuming ducts are
tight, outside air
duct results in
slight positive
pressure in home.

81. 81
Cycling the HVAC Blower
HVAC Cyclers are low cost devices attached to the air handler
cabinet and connected to the low-voltage thermostat wiring block
inside the air handler. By periodically operating the central heating
and cooling system fan, they improve the effectiveness of the
temperature control, humidity and filtration system in a house.
Products:
Air Cycler
April Aire Controller

82. 82
Central
exhaust
fan
Dampered
outside air duct
Central heating and cooling
system
Example of central exhaust
fan: the “Octopus” – from
American Aldes
Whole House Ventilation System

83. 83
Central Ventilation System
• “Pick-up” ducts
connected to
bedrooms and
bathrooms
• 3-speed blower is
typical
• Example supplier –
American Aldes

84. 84
Stale room air return
ducts
Heat recovery ventilator
(not part of HVAC system)
Exhaust air
outlet
Fresh air inlet
Heat Recovery Ventilation (HRV)

85. Heat Recovery Core
85
Heat Recovery Ventilator

86. 86
• Check for minimum natural ventilation
• Check ventilation equipment
• Test for backdrafting problems
• Test pressure balance
Ventilation and Air Quality Testing

87. 87
EPA Mold Resources
• A Brief Guide to Mold Moisture and Your
Home
• Mold Remediation in Schools and Commercial
Buildings
www.epa.gov/iaq/molds/moldresources

88. 88
Energy Myth
88
Never build a house “too tight!”

89. 89
Typical Sources of Air Leakage in the Home
89

90. 90
Which Subcontactors Are Key?

91. 91
• 0.35 air changes per hour, or at least 15 cfm per
occupant
• New ASHRAE 62 Residential
7.5 cfm per person + 0.01 x floor area
• Kitchen exhaust fans
– 100 cfm intermittent or 25 cfm of continuous fresh
air or operable window
• Bathroom exhaust fans
– 50 cfm intermittent or
– 20 cfm continuous fresh air or operable window
ASHRAE 62 (not revision): Minimum Ventilation
Requirements for Indoor Air Quality

92. 92
Estimating Natural ACH
1. Conduct blower door test - find ACH50 = CFM50 x 60/
volume
2. Find factor in table:
3. ach = ACH50/ factor in table
Number Degree of Protection
of
Floors Exposed Average Good
1 18.9 21 25.2
1.5 17 18.9 22.7
2 15.1 16.8 20.2
2.5 14.2 15.8 18.9
3 13.2 14.7 17.6
over 3 12.3 13.7 16.4

93. 93
• 2-story home with 4 bedrooms
– Area = 2,000 sq ft; Volume = 16,000 cubic feet
– Good protection from wind
– 10 ACH50 on blower door test
• Natural air changes per hour
– From table, ach Factor = 20.2
– ach = ACH50/ach Factor = 10 / 20.2 = 0.5
(often used in computer load sizing and energy
estimating calculations)
Example - Natural ACH

94. 94
Example : ASHRAE 62 - cfm Requirement
• Required minimum cfm by ASHRAE 62 =
(# of bedrooms + 1) x 7.5 cfm + (0.01 x area) =
((4+1) x 7.5) + (0.01 x 2000) = 57.5 cfm
• Measured cfm for home = ach x volume / 60
= 0.5 x 16,000/ 60 = 133 cfm, which complies since it
exceeds required minimum of 57.5 cfm

95. 95
Blower Door/ ASHRAE 62 Homework
• A home has a bottom floor measuring 24 feet x 48 feet and
has 10 foot ceilings. The second floor measures 18 feet x 48
feet, but has a sloped ceiling that is 8 feet high at its lowest
point and 16 feet high at its apex. The ceiling runs this way
along the entire 48-foot length.
• During a blower door test, you have a house pressure of 50
Pa, fan pressure of 225 Pa, and 4,500 cfm of air flow out the
blower.
• What is the CFM50 and the ACH50?
• Does the home comply with the old ASHRAE 62? (Assume
average shielding – factor from table is 18.9.)

96. 96
Maximum Allowable Carbon Monoxide
Carbon monoxide poisoning affects people by cutting off the
supply of oxygen to muscles and the brain. The harmful
effects depend on both the concentration of CO in the air
and the length of exposure.
– 9 ppm ― ASHRAE
– 35 ppm ― 8 hour period
– 100 ppm in flues ― some duct repair programs
– 400 ppm in flues ― EPA

97. 97
Carbon Monoxide Hazards
Concentration Inhalation time and toxic symptoms
developed
200 ppm* Slight headache, tiredness, dizziness, nausea
after 2-3 hours.400 ppm Frontal headaches within 1-2 hours; life
threatening after 3 hours.
800 ppm Dizziness, nausea and convulsions within 45
minutes; unconsciousness within 2 hours.
Death within 2-3 hours.
1,600 ppm Headache, dizziness and nausea within 20
minutes. Death within 1 hour.
3,200 ppm Headache, dizziness and nausea within 5-10
minutes. Death within 1/2 hour.
6,400 ppm Headache, dizziness and nausea within 1-2
minutes. Death within 10-15 minutes.
12,800 ppm Death within 1-3 minutes
*Maximum CO concentration for exposure at any time as
prescribed by OSHA. Effects can vary significantly based on age,

98. 98
Summary
• Minimize pollutants in products – there are
alternatives available
• Install radon mitigation system
• Build as tightly as possible
• Control humidity levels
• Control moisture
• Provide effective controlled ventilation