Jeffrey C. May, M.A.May Indoor Air Investigations, LLC
Tyngsborough, MA
My Office is Killing Me:Surviving the
Sick Building Syndrome
Sponsored by MassRecycle,Bentley University, 6/15/10 We have taken andWe have taken and
analyzed byanalyzed bymicroscopy overmicroscopy over
25,000 air and dust25,000 air and dustsamples.samples.
Since 1992,Since 1992,we have completedwe have completed
more than 1,500more than 1,500““sick buildingsick building
investigationsinvestigations”” ininhomes, schools,homes, schools,businesses andbusinesses and
offices.offices.
May Indoor Air Investigations LLC
Even LEEDBuildings
haveProblems
May Indoor Air Investigations LLC© 2009 Stata-artslibraryMay Indoor Air Investigations LLC
About 40% of Our Energy IsConsumed By Buildings
Green buildings must be energy efficient
Increased efficiency of mechanicalequipment is mandated
Well-insulated and “tight” buildingssave energy
May Indoor Air Investigations LLC
But fresh air must besupplied.
This requires ENERGY andmechanical systems with
ducts.
May Indoor Air Investigations LLC
15 cubic feet of fresh airper occupant per minute inschools, 20 cfm in offices
This air must beheated in winter and
cooled and dried in summer
May Indoor Air Investigations LLC
Windows that only openWindows that only openwhen they fall outwhen they fall out
All the air webreathe indoors
has passedthrough themechanical
system:
The Dark Passage
May Indoor Air Investigations LLC
© 2008 J. May
© 2002 Rick Hughes
The dark passagethrough ducts
May Indoor Air Investigations LLC
© 2008 J. May
The dark passageMay Indoor Air Investigations LLC© 2008 J. May
Why do we have so manyIAQ problems?
Part of the answer is mold!May Indoor Air Investigations LLC© 2009 J. May
Tip:There should be no
exposed fibrous liningmaterial near a coolingcoil or within about 20feet of the air handler
supplyMay Indoor Air Investigations LLC
The Most Common ProblematicIndoor Mold Genera from
A/C Systems:
Cladosporium
Aspergillus
Penicillium
May Indoor Air Investigations LLC
May Indoor Air Investigations LLC © 2009 J. May
Cladosporium Mold on Fiberglassfrom A/C liner
Skin scale
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Cladosporium mold in the air froman A/C supply
May Indoor Air Investigations LLC© 2009 J. May
Dirty Cladosporium spores in theair from an A/C supply
May Indoor Air Investigations LLC
© 2009 J. May
Aspergillus mold in the airfrom an A/C supply
From the office of client with hypersensitivity pneumonitis
Skin scales
Aspergillus
Why Does Mold Grow?
FoodOxygen
Correct temperature rangeMoisture
May Indoor Air Investigations LLC© 2009 J. May
Dew PointThe dew point is the temperature at
which moisture in air starts to condense
On dry days, the dew point is low
On humid days, the dew point is high
May Indoor Air Investigations LLC© 2009 Wikipedia
Dew-point condensation in acrawl space:
85% RHMay Indoor Air Investigations LLC© 2009 J. May
A/C duct
Change in Relative Humidityof 60ºF Dew-Point Air
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Mold growthMold growth
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Where there is high RH and dust,microbial growth is very likely.
© 2010 J. May
Skin scale
Spores
Skin scale
© 2010 J. May
Aspergillus on a blower blade
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All New CommercialBuildings and Most New
Homes Are Built WithCentral Air Conditioning
May Indoor Air Investigations LLC© 2010 J. May
The Paradox ofAir Conditioning
When air in most climates isWhen air in most climates iscooled, moisture condenses oncooled, moisture condenses on
the cooling coil, wetting anythe cooling coil, wetting anyaccumulated dust.accumulated dust.
WET DUST=MICROBIAL GROWTHWET DUST=MICROBIAL GROWTHMay Indoor Air Investigations LLC
The “Six-HundredSick Structures” Study
We compared 600We compared 600 ““sick housessick houses””toto
300 control homes300 control homesrandomly chosen from thoserandomly chosen from those
that had been inspected as partthat had been inspected as partof preof pre--purchase agreements.purchase agreements.
May Indoor Air Investigations LLC May Indoor Air Investigations LLC© 2008 J. May
0 10 20 30 40 50 60 70
Forced hot airheat
Central airconditioning
Finished/carpeted basements
Wall-to-wallcarpeting
Basementmoisture stains
Percent
Randomly selected homes SHS home
Table I: Comparison of Randomly -Selected Homes and SHS Homes
37%
19%
May Indoor Air Investigations LLC© 2010 J. May
Moldy Mat on A/C Coil
Mold Growth in A/CMold Growth in A/C--Coil Dust MatCoil Dust Mat
© 2010 J. May May Indoor Air Investigations LLC
White OxideWhite OxideOnOn
MoldyMoldyInsulationInsulation
Near anNear anA/C CoilA/C Coil
May Indoor Air Investigations LLC © 2010 J. May
Spores from insulation near the A/C coilSpores from insulation near the A/C coil
Mold Spores (Dead or Alive)Mold Spores (Dead or Alive)Cause Allergy and AsthmaCause Allergy and Asthma
SymptomsSymptoms
© 2010 J. May
May Indoor Air Investigations LLC
Microbial Growth Occurs WhereverThere is Dust and a Heat ExchangerThat Cools Air Containing Moisture
May Indoor Air Investigations LLC
© 2010 J. MayRust
Dust
Mold
May Indoor Air Investigations LLC© 2010 J. May
Dried Bioslime and Rust
A source of “surrogate” allergen
Filtration is the key!!!
May Indoor Air Investigations LLC
© 2010 J. May
NOT with an open slotor typical
furnace filter
Filtration
ASHRAE Guideline Is a Minimum ofMERV 8
For families with allergies, I alwaysrecommend MERV 11.
May Indoor Air Investigations LLC© 2009 J. May
© 2008 J. May
The Coil isStill Clean AfterTwo Seasons
May Indoor Air Investigations LLC
A/C Systemwith a
MERV-11Media Filter
Most biodegradable particles in theair, such as skin scales, pollen andlint are trapped by a MERV-8 filter.
Preventing the accumulation of dustminimizes the chances for microbial
growth even at high RH.
May Indoor Air Investigations LLC
With efficient filtration there isno mold, no bioslime, no cloggedcondensate pans, no overflowing
air handlers.
Disposable filters such aspleated media filters are best.
(Electronic filters need too frequentcleaning) May Indoor Air Investigations LLC May Indoor Air Investigations LLC
It is essential for any mechanicalequipment to have an efficient filter
if there is air flow anda heat exchanger that cools air or
creates condensate:
Air ConditionersAir ConditionersAirAir--toto--Air Heat ExchangersAir Heat Exchangers
DehumidifiersDehumidifiers
Moldy dust on filter
May Indoor Air Investigations LLC © 2010 J. May
Window Air Conditioners are not Immune
Original filters areall inadequate!!!
Mold on a Window-A/C Blower
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© 2010 J. May
Who is Negligent?
Given what we know,how can a responsiblemanufacturer sell any
appliance having acooling coil with
anything less than aMERV 8 Filter????
May Indoor Air Investigations LLC
The toll of energy efficiency:
The blowers cannot support thestatic pressure of a decent filter.
Mini-split A/C manufacturer:“Unit will not work with MERV-8
filter.”
May Indoor Air Investigations LLC© 2009 J. May
To avoid bioaerosolproblems:
MERV-8 filters must be used
Coils and blowers must be clean
Avoid exposed fibrous liners
May Indoor Air Investigations LLC© 2009 J. May
What do you do if you the IAQmakes you sick in an office????
Check the HVAC system first!Look for visual problems
Other common sources of IAQproblems:•Carpets
•VOC off gassingMay Indoor Air Investigations LLC
Can bioaerosol testing tell you ifthere is a problem????
The results depend on thetype of testing.
Testing for culturable (live) sporesalways underestimates the size of
the problem.
May Indoor Air Investigations LLC
Bioaerosol testing shouldalways include total (viable and
non-viable) spore counts
A simple comparison withoutdoor counts may not be
relevant….
if spores indoors are present inchains May Indoor Air Investigations LLC
Some simple “tests”:
Monitor carbon dioxide (PM2200)www.airtest.com
Cover carpet (carpet protector)www.pro-tect.com
Purchase a VOC or CH20 test kitwww.pati-air.com
May Indoor Air Investigations LLC
Some simple “tests”:
For possibly allergenic particles,wear an N-95 particle mask
Temporarily cover supplies
For VOC, try wearing a charcoalrespirator
May Indoor Air Investigations LLC
For more tips, guidance and informationon how to read reports: To avoid VOC problems:
Encourage non-smoking policies
Encourage fragrance-free offices
Avoid unvented solvent use
Attend today’s workshops!May Indoor Air Investigations LLC
© 2009 J. May
All Tight Buildings Must HaveFresh Air
Many will use air-to-air heatexchangers for ventilation.
May Indoor Air Investigations LLC© 2009 J. May
May Indoor Air Investigations LLC
HRV/ERV Schematic
© 2010 NuTech
© 2009 J. May
HRVHRV’’ss areare ““greengreen””
IndoorAir
Blower
OutdoorAir
Blower
Core
HRVs need maintenance
May Indoor Air Investigations LLC
© 2009 J. May
Fresh-Air Intake Side
Fresh-AirIntake Side
May Indoor Air Investigations LLC© 2009 J. May
HRV
HRVs are cryingfor
proper filters
May Indoor Air Investigations LLC
© 2009 J. May
May Indoor Air Investigations LLC© 2009 J. May
Turn-of-the-Century HRV Filterwith Mold Growing in Dust
Precision filtrationPrecision filtration
HRV
May Indoor Air Investigations LLC© 2009 J. May
HRV with loose, soiled filterMay Indoor Air Investigations LLC© 2009 J. May
HRVs Must Not HaveExposed Fibrous Liner
May Indoor Air Investigations LLC
© 2009 J. May
Surfaces must be cleanable
HRVDefrost “System”
A grow light forduct perfume?
May Indoor Air Investigations LLC
© 2009 J. May
A Temporary Solution:HRV with external, in-line
filtration
HRVOutdoor
Exhaust
Me
dia
filte
r
Indoor
Med
iafil
ter
Supply
MERV-8 MERV-8
Air Air
May Indoor Air Investigations LLC
© 2009 J. May
Drain
Fantech FB6 Inline Filter box
May Indoor Air Investigations LLC
Use MERV-8 instead of MERV-12
An Optimistic Note:HRV Can Improve Air Quality
By Diluting Contaminants
May Indoor Air Investigations LLC© 2009 J. May
The New Kitchen Cabinets WereOff-Gassing Formaldehyde
May Indoor Air Investigations LLC © 2009 J. May
The room odor disappearedafter the HRV was turned on. Dehumidifiers need
efficient filtration too!
May Indoor Air Investigations LLC© 2009 J. May
Dehumidifier MoldMay Indoor Air Investigations LLC
© 2009 J. May
© 2009 J. May
Dehumidifier Snot
May Indoor Air Investigations LLC
Anything with aAnything with acooling coilcooling coil
mustmusthave at least ahave at least a
MERVMERV--88media filter!media filter!
May Indoor Air Investigations LLC© 2009 J. May
For Manufacturers,It’s Wake-Up TimeLadders, cigarettes,
liquor and evencoffee cups have
consumer warnings!
May Indoor Air Investigations LLC
ItIt’’s time for mechanical equipment tos time for mechanical equipment tocome with a warning label:come with a warning label:
WARNING: The incoming air must befiltered to avoid microbial contamination.
ASHRAE recommends that you use a filterwith a rating of at least MERV-8. Failure to
maintain filtration can lead to illness.
20082006
20042001
Questions?
For PDF of talk: [email protected]
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