InspectAPedia ^®

Killer house dust - a case history: Mystery dust identified as cotton, ending dispute with contractor

We'd be concerned about finding high levels of problematic mold spores, and I'd not like to find a lot of fiberglass in the sample either, both because it may be a health concern and because it'd argue for sloppy work by the contractor.

House dust from an occupied home contains lots of stuff, usually dominated by skin cells and fibers from clothing and upholstery or carpets. Animal dander, particularly from dogs, cats, or mice, may be present at high levels too. In inner-city apartments I find lots of insect fragments as well, possibly cockroach allergens.

And everybody's dust can be expected to have traces of dust mites, usually their fecal pellets. By examining the pellets I can often determine what the mites are eating, for example mold spores.

The dust sample was examined for homogeneity and then prepared for a look at high magnification in my lab, using both ordinary and polarized light. The latter helps quickly separate out synthetic fibers such as Orlon or Nylon, as well as distinguishing typical road grit and fiberglass.

Remarkably the dust sample from this West coast home was unusually clean. The sample was 90% cotton fibers, mostly blue with a few red ones included. There were incidental (not statistically significant) wool fibers present too. Skin cells were another 8% of the sample, and typical drywall dust and road dust made up the rest.

The sample contained no mold spores, no fiberglass, no heating fuel combustion products, no ash, no paint droplets, in other words, it was cotton from a mostly blue fiber source.

This is not your heating system folks.

Without making a site inspection I can still offer some useful speculation: I'd look for something new in the home, carpets, drapes, upholstery, bedding, and I'd guess that mechanical disturbance like foot traffic, vacuuming, or other activity was combining with air movement from the HVAC system to spread dust around. Naturally, an investigator is a lot smarter when on-site than when speculating by telephone. But in any case, this was the end of arguing with the HVAC contractor.

...

Technical Reviewers & References

Search InspectAPedia

• Daniel Friedman - principal author/editor of the InspectAPedia^® Website
• InspectAPedia Bookstore lists recommended books, organized by topic & available for purchase. Most of our articles also include a list of recommended books for the specific article topic as well as other references, and information sources.
• Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
• Additional technical contributors & reference sources for this article are listed below.

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

HVAC HOUSE DUST CONTAMINATION STUDY
THERMAL TRACKING
THERMOSTATS
STAIN DIAGNOSIS on Indoor Surfaces

More Information on Building Diagnostic Inspections and Repairs

• Carbon Monoxide & Carbon Dioxide Gas Toxicity
• Dust from HVAC? An Investigation of Indoor Dust Debris Blamed on a Heating/Cooling System Reveals Carpet Dust
• Goodman Furnace High Temperature Plastic Vent HTPV safety recall US CPSC notice
• Home Heating System Should Be Checked [for proper venting and for CO Carbon Monoxide Hazards - DJF]
• Inspection Procedures for Oil-Fired Heating Systems Detailed step by step approaches for inspecting complex systems]
• Lennox Pulse Furnace Safety Inspection/Warranty Program: Carbon Monoxide Warning
• Oil Tanks - The Oil Storage Tank Information Website: Buried or Above Ground Oil Tank Inspection, Testing, Cleanup, Abandonment of Oil Tanks
• Oil Tanks Above Ground, UL Standards, guidance for home owners, buyers, and inspectors
• Plastic Heating Vent Pipe & Other Heating Safety Recall Notices
• Weil McLain Model GV Gas Boiler/gas valve CPSC recall/repair

InspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.

The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems

Use this simple, economical mold test kit by following our instructions on how to collect and mail mold samples to our lab

Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.

Building Inspection, Problem Diagnosis, Forensic Investigation & Testing, Repair Consulting

Contact Daniel Friedman for website content suggestions or for fee-paid consulting