Ed Light, CIH – Limitations & Alternatives to IAQ Testing; To Test or Not to Test?

Air Date: 11-14-2014 | Episode: 347

This week IAQ Radio welcomes back Mr. Ed Light, CIH to discuss alternatives and limitations to IAQ Testing. Is the industry too reliant on testing?…

Full Description:

This week IAQ Radio welcomes back Mr. Ed Light, CIH to discuss alternatives and limitations to IAQ Testing. Is the industry too reliant on testing? What is the science behind clearance testing for mold? What is the science behind the LEED VOC testing requirements? What is the engineering approach to clearance? Times change, the science changes, people change but we still see many of the same clearance methods that were used 15 years ago. What are the limitations of these methods and what are the alternatives?

Mr. Light has specialized in the indoor environmental sciences since 1982, when he directed a pioneering IAQ Program for the West Virginia Department of Health. A Senior Fellow of the American Industrial Hygiene Association, he has published extensively. As a consultant with Building Dynamics, he has conducted over 1000 IAQ investigations, including assessments of the White House, South Pole Station and Sing Sing Prison. In his other life, Ed is lead singer and first chair banjoist with the All New Genetically Altered Jug Band and author of There’s A Fungus Among Us!



Z-Man’s Blog:



As a CIH, Ed Light has specialized in IAQ for over 30 years. I admire his down to earth practical approach. Ed has the knack for explaining complicated subject matter in simple easy to understand terms. Whether you consider him strong advocate or outspoken contrarian, you always know what Ed thinks. In addition to strong reasoning and scientific skills, he is blessed with a sense of humor and musical talent.


Nuggets mined from today’s episode:


  • Today’s interview started with the question: can we make good judgments based on IAQ based on contaminate sampling? There is very little conclusive findings result from testing. There are 3 reasons to test; 1) Is the air healthy? There are no standards which are accepted by public health authorities. 2) Is the air acceptable? Sampling is generally not representative and doesn’t account for normal background levels, and 3) Verify remediation? Mold sampling doesn’t answer the restoration question.
  • The AIHA Green Book is a bible, a book which can be interpreted many different ways. Testing results can look impressive but doesn’t provide answers to important questions.
  • Containment: — Containment should be a professional judgment call not based on an arbitrary magic number. On Ed’s projects, are often allowed to use critical barriers and cover surfaces. He isn’t fussy about containments on water damage restoration sites because site will be thoroughly cleaned and sanitized as part of remediation. Containments should be project/site specific. Full containment should be used when spaces are occupied or for sensitive people or to facilitate cleanup.

– Mold consultants must understand and eliminate moisture problems. Some mold projects fail due to ongoing moisture problems.

  • IAQ epidemiological research has often been based on limited air sampling data that doesn’t reflect overall exposure.
  • Instead of sampling, recommends a general investigation for site assessment: inspection for IAQ indicators, potential sources and pathways, interviewing O&M personnel and occupants (complainers and non-complainers) and evaluating mechanical systems, looking for consistency with building performance standards possible associations with symptom patterns.
  • PRV should answer: have building repairs, restoration and final cleaning/sanitizing been performed properly? Does the remediated area look and smell clean?
  • Sensitive occupants: Another goal of PRV is to verify that the remediated area is safe and healthy for the general population of occupants. It may not be possible to please everyone. Do the best you can for the sensitive occupants.  Do sensitive occupants experience the symptoms in other environments? Work closely with physicians when health issues are involved to try and resolve sensitive occupants on an individual basis.
  • Surface sampling for PRV makes conclusions based on small — spots, while inspection answers questions about what needs to be fixed. Air sampling is inconclusive because bio-aerosol levels are not associated with mold growth or health effects.

– Random sampling doesn’t identify critical problems, average or occupant exposure. Ed has seen excellent restoration projects where the remediation solved the problem and the project failed PRV sampling.

  • Opines mold sampling is irrelevant for water damage.
  • Ed is aligned closely with engineers and most of his staff are engineers. Ed advocates  taking an engineering approach to building investigation. It’s important for inspectors to  understand the history and pathways of water intrusion,
  • Ed’s firm doesn’t believe in simply signing off at the end of the project. They only work on projects on which they can: assess, design remediation program, help contractor perform successful remediation by being onsite during the dirty work.
  • LEED VOC sampling is not scientifically based. — 25 years ago emissions from building materials and furnishings was a real problem, today not so much. Great strides have been made in eliminating the materials emission problem. Today following construction there is very little detectable odor.

– LEED’s list of VOCs is flawed. LEED’s new VOC list is based on a California list of hazardous materials. Many of the chemicals on the LEED VOC list aren’t important to IAQ. Many of the VOCs on the LEED list have sources other than building materials and furnishings and are present as background both indoors and outdoors. LEED’s sampling exceeding VOC standards often places blame on building materials and contractors unjustly. — LEED’s list of VOCs isn’t many compounds released from materials and does not answer the question of whether the IAQ in a building is healthy. —

  • LEED does not address critical  moisture issues. Some LEED Gold buildings have massive moisture problems.
  • Too much emphasis on mold. Mold blamed when other conditions or factors are responsible for complaints.


9/11 Case Studies:

  • Occupants getting sick in building located ½ mile from ground zero. Owner said safe based on air sampling. Engineering IAQ review found significant exposure to ongoing particulate emissions from World Trade Center infiltrating the building. Complainants had pre-existing respiratory conditions and experienced the same symptoms during commute to work.
  • Reviewed owner’s PRV testing for tenant. in building across street from ground zero. Ed found ductwork visibly contaminated and dust trapped in furniture despite passing initial tests. Building later failed final clearance based on surface dioxin criteria which Ed found were consistent with urban background.


Today’s Music: “A Fungus Among Us” performed live by Ed Light


Z-Man Signing Off