Indoor Air Quality Improvements
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Question: is an indoor mold spore count of 29,100 and 689 Aspergillus harmful?

Is an indoor spore count of 29,100 and a raw count of 689 of Aspergillus a harmful level? My daughter has moved into an apartment we feel has a heavy musty odor of mold and we are concerned. We had testing done and we are having trouble understanding the test results. Thanks! - Willie 8/13/2011

Reply: maybe

Willie the interpretation of a spore count, given the huge variability from moment to moment of indoor particle levels, has meaning mostly if interpreted by an expert who also has actually inspected the building. I have no trust in "raw" indoor airborne particle counts - I'm not even sure what your report means by that number, but in any event, we need to know not just how many of particle x there are in a building but how big a percentage of all particles they form.

• 700 spores out of a total particle level in the millions per cubic meter is nothing.
• But 700 spores as the dominant particle in a dust sample would be suggestive of a problem even if the absolute count is low.

When you have some idea what your "mold tester" was up to, then the article titled MOLD CONTAMINATION LEVELS
may help put it into perspective. There you will see that while building air quality experts have reasonably consistent opinions about indoor mold levels that suggest a water-contaminated building (and possibly hidden a mold reservoir to be found and removed) that would agree that 30,000 mold spores/M³ of air could indicate a problem, a more accurate answer is ... it depends. For example, collecting an indoor air particle sample while indoor air is being stirred by fans or an HVAC system will give airborne counts that are one to two orders of magnitude (10x to 100x) the count you'd get in quiet still indoor air conditions.

In my OPINION whomever you paid should not just have thrown a lab report over the wall to you - they owe you something for their fee, no?

at MOLD / ENVIRONMENTAL EXPERT, HIRE ? we include some criteria for helping decide when further investigation for a hidden mold contamination problem is in order.

Question: the air quality in our house is causing breathing issues with everyone - the mold inspector didn't see a problem and recommended an air exchange unit

The air quality in our house is causing breathing issues with everyone in the house. A certified mold inspector just looked at our house and saw no water issues nor mold issues. Our dehumidifier in the basement needs to be emptied 3x a day. She suggested replacing the humidifier with an air exchange system like Humidex. Is that a reasonable step to take or should we get some other inspector in? - Barbara 8/16/11

Reply: dilution of contaminated air versus finding and removing the contaminant is the question?

Barbara, the swap out of a portable dehumidifier to an air to air exchange unit would be expected to add outdoor fresh air into the home, perhaps diluting an indoor contaminant, irritant, or pollutant. It's not an unreasonable suggestion ("how-to" advice is at VENTILATION, BALANCED), but it begs the question.

If no one has diagnosed a problem in the home no one knows what's wrong or what needs to be fixed, so we don't know if there is not something more harmful, or urgent, that should be corrected. You could wear a HEPA filter respirator while indoors too, and might feel better if the problem in indeed due to indoor air particles, but still no one would know what problem to address in the home.

Lots of "certified" inspectors have taken a class and obtained a certification; we document here that some mail-order certifications are very easy to obtain. In my experience and opinion, many mold experts are neither expert in mold, knowing little about mycology, for example, nor experts in indoor air quality and building science. Too many are accepting a fee for collecting some samples that are sent to a lab, and perhaps a too-superficial inspection.

I would take a look at the article titled MOLD / ENVIRONMENTAL EXPERT, HIRE ? and perhaps find someone in whose experience and depth and care you have confidence.

Reader follow-up:

The issue seems to be dampness (not to the touch) from the concrete. When I am away from the home and no one is tending to the dehumidifier constantly the surface mold develops on items conducive to mold growth--certain wood items, baseboards behind bookshelves, cardboard boxes or clothes directly on the concrete floor and the like. My house is on a wooded lot, which is nice and cool in the summer, but may contribute to the general dampness in the basement. Is this still sounding like an air to air exchange unit would be helpful? We are also considering cutting down a tree or two overshadowing our house. Members of the home are seriously affected by the air quality. Would you recommend hiring an expert inspector like Greg Brown or try the air to air exchange unit? (Thank you for your assistance!) - Barbara 8/17/11

Reply:

If you are seeing indoor mold growth there is an indoor humidity problem. All mold is everywhere, all the time. So when indoor conditions are right, depending on the particular indoor surface - what it's made of - some mold spores find it a nice place to begin colonization.

In addition, if there is already an existing indoor problem mold reservoir, perhaps a hidden one, that added inoculation of mold spores (that varies by indoor conditions of light, humidity, temperature, and even season) can speed up the colonization of indoor surfaces.

You need to properly control the indoor humidity, not cutting down outdoor trees. And if there is already indoor mold visible, you need to know the extent of cleanup needed and to have that done effectively.

Question: My vinyl floor smells like B.O. and is making me sick

Hi, hopefully you can help,

My vinyl floor is outgassing. It smells like terrible body odor and is making me sick! Before I put in a claim, I want to educate myself as much as possible. What is it exactly in plastic that breaks down to smell like BO? What other information do you think I should know before I make contact with a claims department?

The [smelly vinyl] floor is Permastone by Tarkett and it was tested by the Resilient Floor Covering Institute and given a floor score as being environmentally sound and complies with California's volatile organic compound emissions criteria. Maybe that was after mine was manufactured.
Thanks,
Amanda 9/30/11

Reply:

Amanda, vinyl flooring outgassing of VOCs usually diminishes rapidly in the days right after installation; outgassing and odors may also be from the adhesive or mastic used to install the floor, not the flooring itself. But yours is the first report we've had of an odor associated with "BO" or body odor.

NAFCO describes five different adhesives that may be used with their flooring products, including one on "self-stick" flooring tiles. Acrylic adhesives are common.

You might want to give Tarkett a call (United States - Phone 800-367-8275 Canada - Phone 800-465-4030) to ask for a copy of the MSDS for both the Permastone product itself and for the adhesive used in its installation. Also download their installation .PDF and check those instructions against what was used by your installer. For example, if an installer did not follow the recommended installation guide - see nafco dot com . The installation manual also details NAFCO's principal concerns (moisture in the subfloor or slab over which flooring is to be installed) that affect their product's performance.

Also see these articles:

VINYL SIDING or WINDOW PLASTIC ODORS
VINYL CHLORIDE HEALTH INFO
VINYL SIDING or WINDOW PLASTIC ODORS

Question: are pressure treated materials toxic to breathe?

I need to know if pressure treated materials are toxic to breath , and how do you get rid of the smell on the pressure treated materials. I have tried sealers[Bin Shellac] and added ventilation under the home .I have 6 by 14 pressure treated beams under the house supporting the main floor. Please advise - Paul MacGregor 3/26/12

Reply:

What and where are your pressure treated materials. Odor complaints from treated lumber are not something we have heard reported before. How did you determine the odor source?

However Paul, if you are talking about sawdust from construction during building of a structure that uses pressure-treated lumber, modern pressure treated lumber typically uses borate salts rather than the more toxic CCA (that contained copper arsenate - an arsenic compound) in older lumber.

Nevertheless, sawdust in general is a respiratory irritant that should be avoided by wearing a proper respirator - we'd recommend a HEPA respirator worn while sawing or sanding treated or any other wood.

Details about the types of wood preservative treatment, health concerns, & working with treated lumber are
at PRESERVATIVE_TREATED FRAMING LUMBER

Question: indoor air contaminants include gases & microbes

(May 20, 2011) Manish K. Verma said:

Here the normal concentration of the contaminants like gases, microbes should be mentioned.

Reply:

Thank you for the suggestion Mannish, see the table just above.

Question: soft water in a dehumidifier

(Feb 6, 2014) Anonymous said:

I use water soften by auqa pur in my dehumidifier and it puts a salt dust in the air and covers my furniture, is this harmful?

Reply:

Really? a dehumidifier removes moisture from building air. More likely you are discussing a humidifier - a device to add humidity to building air.

Please see HUMIDITY CONTROL & TARGETS INDOORS

Question: office flooded, IAQ complaints

(July 24, 2014) Josie said:

Our office was recently flooded due to a plumbing mishap. Because of the water, the walls had to be torn apart, insulation removed & replaced, drywall & studs replaced. The repairs are still ongoing. Anytime I'm in the office now, after about an hour my throat gets itchy, my tongue tingles & itches, I develop a cough, nausea and headache. Could the repairs, open/disturbed insulation, etc be the cause of these new symptoms? thanks for your time.

Reply:

Josie it is possible that the extent of demolition and cleaning were inadequate. Some simple measurements of what is in the indoor dust may be helpful.

Also see FIBERGLASS HAZARDS

Question: office smells rotten

(Sept 11, 2014) Lee Bryant said:

Our office smells like there is something "rotten" and it is usually in the mornings. It seems to not be as bad as the day passes.

Reply:

Lee in the More Reading links above, beginning at

ODOR DIAGNOSIS CHECKLIST, PROCEDURE

we provide suggestions for tracking down odor sources.

Question:

11/30/2014 Glen de Valk said:

Last May we replaced our central air unit in our 2400 sq.ft. home in Sarasota, FL. It was replaced with the same size unit that had been in place for over 20 years (3.5 tons) and cooled and dehumidified very well. However, the new unit does not dehumidify the air regardless where temp. is set and keeps the humidity level no lower than 60% and as high as 72% when we raise the thermostat to our comfort level around 75 degrees. We had an independent inspection of the system done and detected that the air humidity at the registers was 83-85% when the unit was running; when the compressor shuts off and the fan runs for a pre-set 90 seconds more, the humidity level goes to 100%. The installer cancelled the 90 second period of running but the humidity level still stays at 82-85% coming out of the registers and around 60 to 65 % at the returns. The house was also thoroughly tested for plumbing leaks, etc. and there are none. The A/C contractor thought the 3.5 ton unit was too big and replaced it with a 3 ton unit so it would run longer cycles. That made absolutely no difference in dehumidification. The contractor seems to be at a loss to cure it. Please advise. Thanks.

Reply:

Glen, please see your question and our reply in the article at DEHUMIDIFICATION PROBLEMS

...

• Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication
• Steve Bliss's Building Advisor at buildingadvisor.com helps homeowners & contractors plan & complete successful building & remodeling projects: buying land, site work, building design, cost estimating, materials & components, & project management through complete construction. Email: info@buildingadvisor.com
  Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education.
  
  Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com
• [1] "Indoor Air Quality (IAQ) ASHRAE Standard", Ranish Joshi, Arctic India Sales, reviews the basics of IAQ, emphasizes the importance of both source control and removal of contaminants when improving indoor air quality, warns about bringing inside contaminants from outdoors, and reviews the pertinent ASHRAE IAQ standards for buildings.
• [2] "ASHRAE Fresh Air Ventilation System", Jie Chen et als, describes a fresh air ventilation system designed to meet ASHRAE 62.2P Standard.
Updated ASHRAE 90.1 Energy Code May Help Maximize The Benefits Of Energy Efficient Technologies", Lindsay Audin, Building Operating Management, May 2005, discusses ASHRAE Standard ASHRAE 90.1-2004, the latest version of ASHRAE's energy code, encompassing updates to the ASHRAE 90.1-2001 standard.

"Written to allow easy incorporation into specifications for new buildings and renovations, 90.1-2004 lays out minimum requirements for a building’s envelope, electrical power systems and equipment, lighting, heating, Ventilating and air conditioning, service, water heating, and energy management. Under the 1992 federal Energy Policy Act (EPAct), ASHRAE 90.1 was mandated as the basis for all state building codes as they affect energy use, starting with ASHRAE 90.1-1989. Under EPAct, the 1999 version became law in July 2004, but has yet to be adopted by all states.

Since the 1999 version was somewhat dated by the time it became a requirement, some states, especially those having high energy prices, have already updated their building codes to the 2001 version. Some states and cities, such as Phoenix, are now going further by leapfrogging the 2001 edition and enacting part or all of the 2004 edition instead."
• [4] "Energy Efficient Lab Design", Nicolas Lemire, Eng., Member ASHRAE, and Roland Charneux, Eng., Fellow ASHRAE, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Reprinted by permission
  from ASHRAE Journal, (Vol. 47, No. 5, May 2005). ©ASHRAE
• Offermann, Francis (Bud) J., P.E., C.I.H., ASHRAE & Mark Nicas, Ph.D., MPH, C.I.H., USE WITH ADEQUATE VENTILATION ? [PDF], ASHRAE Journal, May 2018, also available as a PDF here with permission of the authors.
  Abstract:
  
  Consumer products such as paints, cleaning chemicals, and adhesives often contain toxic volatile chemicals. When these products are used indoors, these chemicals are released into the air resulting in inhalation exposures to applicators and other occupants.
  
  The resulting indoor concentrations can result in exposures that cause acute adverse health effects, including death, and/or explosion risks.
  
  Warning labels on these products and information in “safety data sheets” often simply caution to “use with adequate ventilation.”
  
  Excerpt:
  Providing consumers with the required ventilation rates and product quantity limitations for indoor applications of paints, cleaning chemicals, and adhesives should significantly reduce adverse health impacts associated with the use of these products.
• [5] Moeckel, W.E.; Weston, K.C., "Composition and Thermodynamic Properties of Air in Chemical Equilibrium", Technical Report NACA-TN-4265, Lewis Flight Propulsion Lab., Cleveland, 1 April 1958, updated 25 February 2008, Website citation: www.osti.gov, U.S. DOE, Abstract:
  Charts have been prepared relating the thermodynamic properties of air in chemical equilibrium for temperatures to 15,000 deg K and for pressures from 10/sup -5/ to 10/sup +4/ atmospheres. Also included are charts showing the composition of air, the isentropic exponent, and the speed of sound. These charts are based on thermodynamic data calculated by the National Bureau of Standards. (auth).
• [6] Bender, M. L., T. Sowers, J.‐M. Barnola, and J. Chappellaz (1994), Changes in the O2/N2 ratio of the atmosphere during recent decades reflected in the composition of air in the firn at Vostok Station, Antarctica, Geophys. Res. Lett., 21(3), 189–192, doi:10.1029/93GL03548.
  Abstract:
  Samples of air at various depths in firn were collected at Vostok Station, Antarctica, and analyzed for δ15N of N2, O2/N2 ratio, and CO2. The ultimate objective of this work is to constrain the recent rate of the atmospheric [O2] decrease, thereby providing a direct experimental constraint on net CO2 fluxes into the ocean and the land biosphere. δ15N increases with depth, because of gravitational enrichment, at approximately the rate predicted by the barometric equation. Gravitationally corrected CO2 decreases with depth to 308 ppmV at 101.9 m depth, because deeper air is older and less contaminated with anthropogenic CO2.
  
  The gravitationally corrected O2/N2 ratio increases with depth mainly because burning fossil fuel consumes O2. Samples in the top 20 m of the firn have anomalously high CO2 concentrations and anomalously low O2/N2 ratios. Samples below 96.2 m depth have anomalously high O2/N2 ratios. Between 30 and 96.2 m depth, the gravitationally corrected increase in the O2/N2 ratio is nearly equal to that computed from the rate of O2 consumption by combustion of fossil fuels. Our results indicate that the rate of anthropogenic O2 consumption can be accurately constrained by future firn air studies.
• [7] A.P. Jones, "Indoor Air Quality and Health", School of Environmental Sciences, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK, Atmospheric Environment Volume 33, Issue 28, December 1999, Pages 4535–4564
  Abstract
  During the last two decades there has been increasing concern within the scientific community over the effects of indoorair quality on health. Changes in building design devised to improve energy efficiency have meant that modern homes and offices are frequently more airtight than older structures.
  
  Furthermore, advances in construction technology have caused a much greater use of synthetic building materials. Whilst these improvements have led to more comfortable buildings with lower running costs, they also provide indoor environments in which contaminants are readily produced and may build up to much higher concentrations than are found outside. This article reviews our current understanding of the relationship between indoorair pollution and health. Indoor pollutants can emanate from a range of sources.
  
  The health impacts from indoor exposure to combustion products from heating, cooking, and the smoking of tobacco are examined. Also discussed are the symptoms associated with pollutants emitted from building materials. Of particular importance might be substances known as volatile organic compounds (VOCs), which arise from sources including paints, varnishes, solvents, and preservatives. Furthermore, if the structure of a building begins to deteriorate, exposure to asbestos may be an important risk factor for the chronic respiratory disease mesothelioma.
  
  The health effects of inhaled biological particles can be significant, as a large variety of biological materials are present in indoor environments. Their role in inducing illness through immune mechanisms, infectious processes, and direct toxicity is considered. Outdoor sources can be the main contributors to indoor concentrations of some contaminants.
  
  Of particular significance is Radon, the radioactive gas that arises from outside, yet only presents a serious health risk when found inside buildings. Radon and its decay products are now recognised as important indoor pollutants, and their effects are explored. This review also considers the phenomenon that has become known as Sick Building Syndrome (SBS), where the occupants of certain affected buildings repeatedly describe a complex range of vague and often subjective health complaints.
  
  These are often attributed to poor air quality. However, many cases of SBS provide a valuable insight into the problems faced by investigators attempting to establish causality. We know much less about the health risks from indoorair pollution than we do about those attributable to the contamination of outdoor air.
  
  This imbalance must be redressed by the provision of adequate funding, and the development of a strong commitment to action within both the public and private sectors. It is clear that meeting the challenges and resolving the uncertainties associated with air quality problems in the indoor environment will be a considerable undertaking. Keywords Biological particles; Combustion pollution; Radon; Sick building syndrome; Volatile organic compounds
• [8] H. Frommea, D. Twardellaa, S. Dietricha, D. Heitmannb, R. Schierlc, B. Liebld, H. Rüdene, "Particulate matter in the indoorair of classrooms—exploratory results from Munich and surrounding area", Atmospheric Environment, Volume 41, Issue 4, February 2007, Pages 854–866
  Abstract
  Numerous epidemiological studies have demonstrated the association between particle mass (PM) concentration in outside air and the occurrence of health related problems and/or diseases. However, much less is known about indoor PM concentrations and associated health risks. In particular, data are needed on air quality in schools, since children are assumed to be more vulnerable to health hazards and spend a large part of their time in classrooms.
  
  On this background, we evaluated indoorair quality in 64 schools in the city of Munich and a neighbouring district outside the city boundary. In winter 2004–2005 in 92 classrooms, and in summer 2005 in 75 classrooms, data on indoorair climate parameters (temperature, relative humidity), carbon dioxide (CO2) and various dust particle fractions (PM10, PM2.5) were collected; for the latter both gravimetrical and continuous measurements by laser aerosol spectrometer (LAS) were implemented. In the summer period, the particle number concentration (PNC), was determined using a scanning mobility particle sizer (SMPS). Additionally, data on room and building characteristics were collected by use of a standardized form.
  
  Only data collected during teaching hours were considered in analysis. For continuously measured parameters the daily median was used to describe the exposure level in a classroom.
  
  The median indoor CO2 concentration in a classroom was 1603 ppm in winter and 405 ppm in summer. With LAS in winter, median PM concentrations of 19.8 μg m−3 (PM2.5) and 91.5 μg m−3 (PM10) were observed, in summer PM concentrations were significantly reduced (median PM2.5=12.7 μg m−3, median PM10=64.9 μg m−3).
  
  PM2.5 concentrations determined by the gravimetric method were in general higher (median in winter: 36.7 μg m−3, median in summer: 20.2 μg m−3) but correlated strongly with the LAS-measured results. In explorative analysis, we identified a significant increase of LAS-measured PM2.5 by 1.7 μg m−3 per increase in humidity by 10%, by 0.5 μg m−3 per increase in CO2indoor concentration by 100 ppm, and a decrease by 2.8 μg m−3 in 5–7th grade classes and by 7.3 μg m−3 in class 8–11 compared to 1–4th class.
  
  During the winter period, the associations were stronger regarding class level, reverse regarding humidity (a decrease by 6.4 μg m−3 per increase in 10% humidity) and absent regarding CO2indoor concentration. The median PNC measured in 36 classrooms ranged between 2622 and 12,145 particles cm−3 (median: 5660 particles cm−3).
  The results clearly show that exposure to particulate matter in school is high.
  
  The increased PM concentrations in winter and their correlation with high CO2 concentrations indicate that inadequate ventilation plays a major role in the establishment of poor indoorair quality. Additionally, the increased PM concentration in low level classes and in rooms with high number of pupils suggest that the physical activity of pupils, which is assumed to be more pronounced in younger children, contributes to a constant process of resuspension of sedimented particles. Further investigations are necessary to increase knowledge on predictors of PM concentration, to assess the toxic potential of indoor particles and to develop and test strategies how to ensure improved indoorair quality in schools.
• Basement Moisture Control, U.S. Department of Energy
• Building Pathology, Deterioration, Diagnostics, and Intervention, Samuel Y. Harris, P.E., AIA, Esq., ISBN 0-471-33172-4, John Wiley & Sons, 2001 [General building science-DF] ISBN-10: 0471331724 ISBN-13: 978-0471331728
• Building Pathology: Principles and Practice, David Watt, Wiley-Blackwell; 2 edition (March 7, 2008) ISBN-10: 1405161035 ISBN-13: 978-1405161039
• Crawl Space Moisture Control, U.S. Department of Energy
• Energy Recover Ventilation Systems for buildings, U.S. Department of Energy
• Energy Savings Methods: Whole House Systems Approach, U.S. Department of Energy
• Historic Preservation Technology: A Primer, Robert A. Young, Wiley (March 21, 2008) ISBN-10: 0471788368 ISBN-13: 978-0471788362
• Moisture Control in buildings, U.S. Department of Energy
• Moisture Control in Walls, U.S. Department of Energy
• Natural Ventilation for buildings, U.S. Department of Energy
• R-Value of Wood, U.S. Department of Energy
• Spot Ventilation for houses, U.S. Department of Energy
• Slab on Grade Foundation Moisture and Air Leakage, U.S. Department of Energy
• "Vapor Barriers or Vapor Diffusion Retarders", U.S. DOE: how vapor barriers work, types of vapor diffusion barriers, installing vapor barrier
• Ventilation for energy efficient buildings, Purpose, Strategies, etc.,
• Weather-Resistive Barriers, how to select and install housewrap and other types of weather resistive barriers, U.S. DOE
• Whole House Ventilation Systems, U.S. Department of Energy
• Whole-House Balanced Ventilation Systems, U.S. Department of Energy
• Whole-House Exhaust Ventilation Systems, U.S. Department of Energy
• Whole-House Supply Ventilation Systems, U.S. Department of Energy
• ...

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

• Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
• ...