Abstract This scientific preprint presents a physicochemical framework for interpreting divergence between biological and chemical indicators across airborne, dust, and surface analytical domains in indoor environments. Although these domains are often treated as interchangeable during building investigations, they represent distinct transport, deposition, and persistence behaviors that influence exposure relevance. The manuscript defines domain boundaries and explains how particle size distribution, aerosol dynamics, and surface accumulation produce mechanistically consistent divergence among spore measurements, dust indicators, and airborne chemical signals. By separating inhalation-relevant airborne indicators from time-integrated surface reservoirs, the framework clarifies why cross-domain comparisons can produce apparent inconsistencies and how those differences should be interpreted within an exposure context. Emphasis is placed on aerosol physics, environmental transport processes, and domain-aligned inference rather than procedural instruction. The framework is intended to support consistent interpretation and communication of environmental data by Indoor Environmental Professionals and clinicians evaluating building-related exposure questions. Scope This document provides a descriptive and interpretive framework for environmental measurement behavior. It does not establish regulatory thresholds, remediation criteria, clinical standards, or diagnostic guidance. Version v1.0 public preprint release.
Mark Ritacco (2026) studied this question.