Physicochemical Divergence of Mycotoxin and Biological Indicators Across Airborne, Dust Reservoir, and Surface Analytical Domains in Indoor Environments

Assessing indoor mold and mycotoxin exposure requires distinguishing between analytically valid but fundamentally different measurement domains. This paper introduces a physicochemical framework that explains why spore counts, dust-based indicators, and airborne mycotoxin measurements frequently diverge. Spores are large biological particles captured during short-duration sampling. Mycotoxins, by contrast, are chemically stable and non-volatile compounds that may associate with fine and ultrafine aerosol particles or accumulate in settled dust. These metrics therefore represent different particle-size regimes and environmental timeframes.

Drawing from aerosol physics and environmental science, this work describes how aerodynamic behavior, interfacial chemistry, and microenvironmental persistence can decouple airborne mycotoxin presence from spore or dust signals. As a result, airborne mycotoxins may be detected even when spore counts are low or visible mold is absent. Conversely, fungal spores may be detected without measurable airborne chemical signal. These divergences are not errors in sampling but reflect the physical and temporal boundaries of each measurement context.

The paper defines three analytical domains: the Airborne Domain, representing breathing-zone aerosol; the Dust Reservoir Domain, representing time-integrated surface accumulation; and the Surface Domain, representing localized residue. The framework is intended to support domain-specific interpretation of environmental data and consistent communication across scientific and professional disciplines. It does not propose remediation standards, health thresholds, or intervention strategies.