Mold Air Testing: Is there any value?

When folks call our office with a mold concern, they invariably ask for an air test. They say, “I need to know what we are breathing! Can you help us?”

Our response is invariably, “Yes, we can help you. But an air sample for mold is not the proper diagnostic tool.” We go on to describe the more powerful, albeit simple, tools we have available to figure out a mold problem. These tools include a thorough visual inspection, targeting areas where moisture can commonly occur, moisture and humidity testing, and source testing of suspected materials. The goal, after all, is to determine whether an active mold condition exists in the building, not just to identify (usually inaccurately) what is flying around in the air.

There are many reasons why air testing is a poor diagnostic tool. No recognized standard-setting organization has set a numerical standard for acceptable mold air concentrations. The American Conference of Industrial Hygienists (ACGIH), which is the primary standard-setting organization in the United States, explains why in Bioaerosols: Assessment and Control (1999):

“Given the absence of compliance monitoring (OSHA type monitoring) for biological agents, data on the range of inhalation exposures to specific biological agents are limited and methods used to collect and analyze these agents vary widely. Even if limits were set, at present they would be arbitrary standards because the exposure criteria are few and of inconsistent quality.”

“Further, there are more reliable methods to identify environments in need of intervention than by comparing environmental bioaerosol measurements with numerical standards. This book (developed by a consensus of researchers and practitioners under the auspices of ACGIH) defines methods for assessing and controlling exposures to biologically derived airborne contaminants. These methods rely on visually inspecting buildings, assessing occupant symptoms, evaluating building performance, testing potential environmental sources and applying professional judgment.”

Other standard setting agencies in the US, including the Environmental Protection Agency (EPA), American Industrial Hygiene Association (AIHA) and virtually all state Departments of Health, are just as blunt. They warn against the use of air samples as an assessment tool.

Their direction for mold assessment is simple: Figure out whether there are any moisture issues, determine whether the moisture has affected a material (food) that mold likes, and come up with a plan to test these potential mold sources. The EPA calls it “proving your hypothesis”.

The outcome of a competent mold assessment should be a conclusive identification of a mold condition, a defined scope of work, and a straightforward plan to correct the condition. The plan should pertain to your specific problem, not to some imaginary drywall in some abstract place.

Anything less, especially if it includes only air testing, means you have wasted valuable time and money. Choose a consultant who will follow the established assessment protocols.