Session Number 231

Wednesday, October 28, 2020

2:30 p.m. to 3:30 p.m.

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An Air Sample for Mold is Just a Snapshot in Time – or Is It?

It is Time for a Paradigm Shift.

Lisa Rogers - President

Mycometer, Inc., Tampa, Florida

About this program:

The value of air sampling for mold has been seriously questioned by several cognizant authorities. The main problem is the variability of results. Without reproducible results, no interpretation criteria can be developed and no correlation to health issues can be expected. There is a consensus (CDC, US-EPA, ACGIH) that, an air sample is only a snapshot for the moment in time in which the sampling occurred.

Mold spores and hyphal fragments in the air will settle due to gravity. An “average sized spore” will settle at a rate of approximately 1 m per hour in still air. This means that in a room with still air, close to 0 % of the total amount of fungal particles that can become airborne, are airborne. If there is heavy activity in a room (heavy vacuuming, fans running, people dancing) it is likely that close to 100% of the total amount of fungal particles that can become airborne, are airborne.   

The common practice for taking air samples today is to set up the pump and take the sample independent of what activity there has been in the room prior to sampling. This is commonly referred to as passive sampling. In an early study, Swaebly and Christensen,(1) concluded that “Passive sampling can detect the fungal material that is already airborne and is dependent on the level of activity that has taken place within the tested space right before the testing”. An air sample taken using passive sampling, could therefore measure between 0 and 100% of the total amount of fungal particles that can become airborne in a given location.  It is not uncommon that a low amount of airborne mold is  measured in a room with several square meters of mold growth when the air has been still or low activity a couple of hours before sampling.  Contrary, a room with no mold growth and only naturally deposited mold could actually show a higher amount if there were activity just prior to sampling.

This presentation shows results from a study, where the objective was to attempt to standardize room activity by using activated sampling to more fully and reproducibly characterize the existing fungal reservoirs in the space.      

About the Presenter:

LISA J. ROGERS’ BS in chemistry/minor in mathematics from Florida Southern College in no way has defined her career but lay the foundation of a lifelong focus in the environmental health and safety field.   Her experience includes over 30 years in the environmental health and safety field with the focus in the last 20 years on indoor air quality (IAQ) litigation support, expert witness testimony and complex technical evaluations. Her experience earned her an invitation to participate on a NATO Science Advisory Committee developing international guidelines for indoor air quality issues

Ms. Rogers has authored numerous technical papers and various articles for trade newsletters and publications and presented these and other technical issues at national and international conferences.

Currently, Ms. Rogers is Chair of ASTM committee, D22, Air Quality, and Chair of subcommittee D22.08 Assessment, Sampling, and Analysis of Microorganisms, which is developing standard protocols for microbial sample collection and analysis, She is also Head of US Technical Advisory Group (TAG) for  TC 146 SC6 to the International Standards Organization (ISO). Ms. Rogers is a member of the AIHA, Indoor Environmental Quality (IEQ) Committee, the IAQA Education Committee and is serving as Vice Chair for the Board of Directors of the Indoor Air Quality Association and is an Emeritus Director for the Board of the Environmental Information Association. She is also a former member of ASHRAE Standard 62.1, Ventilation for Acceptable Indoor Air Quality for 12 years

 Since 2007, Lisa has served as President of Mycometer Inc. the US subsidiary of a Danish based firm.

Program Level: Basic-Intermediate

Content Area(s): Investigations, Testing & Research