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The Sense and Nonsense of Spore Trap Air Sampling

Posted on: July 3rd, 2014 by Peter Sierck No Comments

To Test or Not to Test – The Sense and Nonsense of Spore Trap Air Sampling

In recent years, more and more consumers are asking for a “mold test” with the expectation of (one) air sample inside the building and (one) outside reference sample. How much information can really be expected from such a limited scope of work and air sampling data?

Mold is present everywhere, at all times on our planet. It is nature’s garbage man whose task it is to decompose organic materials to free the elements and nutrients so that they are back in the soil and available for the next generation of plants – an important role in the circile of life.

Mold spore levels vary significantly in any given location. Limited duplicate sampling, such as two air samples collected at the same time in the same location even shows these fluctuations in variance. One location cannot represent a building assessment, as it lacks an indoor reference location. For professional exposure assessments, numerous duplicate samples must be collected (at different times) to achieve a statistical confidence for true exposure levels, according to recommendations by professional organizations in the indoor air quality industry such as ACGIH –  or the AIHA –

Air sampling can be part of a mold or microbial investigations, but does it assess the present building conditions? Unfortunately, the answer is no. The levels of airborne mold spores do not provide information on the location and extent of a potential mold and moisture problem within the structure. Airborne mold spore or bacteria levels provide information on the potential exposure concerns only if enough data is available. In accordance to EmLab P&K, it is vital to “compare total concentrations from indoors, outdoors, complaint and non-complaint areas” – Collecting only one spore trap sample indoors is simply insufficient! There is a great risk for false positive or false negative conclusions, such that a building with a mold and moisture problem may or may not have any elevated or unusual mold spore levels.

Are all air sampling professionals equal by level of education and quality of practice?  Currently, zero state licensing programs in California exist that would pre-qualify a mold professional. Asbestos and Lead assessors and consultants are going through a training and testing program by State approved schools and testing centers. The asbestos and lead sampling technicians are required to work under the supervision of a fully licensed consultant or assessor. “All levels must keep their license current at the California Department of Public Health (CDPH) with continuous education programs”. –

In California, “mold professionals” do not have to do anything; they can simply show up at your door step and call themselves a professional mold assessor. Do they calibrate their pumps, flow-check them before and after sampling, wipe them down prior to avoid cross-contamination? What is their level of education? Where have they learned industrial hygiene practices? Do they carry any recognized certifications or licenses (such as American Council for Accredited Certification –  or the Indoor Air Quality Association –  These are all questions many consumers are not aware of and bestow their trust in a high Google listing, good looking website and miss-representing sales techniques. All too often, a good deal is too good to be true.

A fact to moisture measurements: Infrared cameras are not moisture meters. They detect temperature differences at the surface of a material which may be evaporative cooling from a material during the drying process…or …a sign for lack of insulation inside the wall cavity. The world’s leading IR Imaging company state that these tools “make it easy to see temperature differences and radiation emitted from objects” –  IR cameras are a good and fast screening tool for surface temperature differences but cannot replace true moisture meters which measure actual moisture content. In contrary to many claims, IR imagers can not look inside wall cavities. In order to truely know what conditions are present, opening up the wall cavity may be the best option.

The approach to collect one indoor and one outside spore trap air sample without a thorough inspection is a sub-standard building evaluation. The reports and laboratory analysis sheets appear to be scientific to the consumer but contain very little site specific information that can actually be used to evaluate or improve the indoor air quality or provide guidance for repairs. The high variance that naturally occurs with airborne mold spore levels is completely overlooked; the benefit for the customer is very limited, to say the least.

A basic mold and moisture assessment of a structure includes: a thorough visual inspection, true moisture content measurements of building materials, possible air sampling in several indoor locations and local outdoor references, possible surface sampling and a detailed site-specific report including recommendations which the customer can use to repair the building, if necessary. To discuss your indoor air quality concerns and develop a professional solution oriented approach, please call us at (760) 804-9400 or contact us at

– Environmental Testing & Technology

Written by Felix Neumann, CMC


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