Asbestos in Settled Dust

Jul 21, 2017

In homes throughout the nation built before the 1980s, asbestos containing materials were commonly incorporated. Asbestos was used because of its high durability, fire resistance, and other favorable properties. Asbestos was used in drywall, plasters, floor tiles, HVAC insulation, plumbing insulation, adhesives, and many other products. Asbestos containing materials in the home become a health risk when they are damaged, disturbed, and made friable, which releases the asbestos fibers into the air. Typically asbestos fibers can remain airborne for up to 72 hours in area of low air movement, afterwards falling to the surface and generating dust.

The larger the release of fibers from asbestos containing materials, the more dust it generates once the fibers settle. As a mineral, asbestos can remain in the dust indefinitely and does not degrade. If an asbestos containing material was improperly abated in a home, this could lead to the settled asbestos dust being disturbed in the future.

Unlike asbestos air testing and inspections, there are no federal or state regulations on settled dust sampling. The bulk of our understanding on asbestos dust is based off of industry guidelines. The method we use at Indoor Science for dust sampling is called TEM Microvac. This process involves taking a filter cassette and attaching it to a high volume air pump, which sucks dust onto the filter.  We generally collect dust from a 100 cm2 area. The cassette is then analyzed at an accredited laboratory by an electron microscope which can scan the cassette and identify the amount of asbestos fibers found. This method is called TEM, which stands for Transmission Electron Microscopy).  

The laboratory reports the results as asbestos structures per square centimeter.  As previously stated, there is no governmental regulation for a permissible amount of asbestos fibers in the dust.  Nevertheless, there are industry guidelines that help us interpret if the fibers found in the dust are background levels, elevated, or highly elevated.

If you have concerns about settled asbestos dust in your home. Feel free to contact us.