Temporal Persistence of Viral Viability on Indoor Surfaces
Surface contamination is admissible as short-lived only if viral infectivity reliably decays within assumed time windows under ordinary indoor conditions. If persistence exceeds these windows, temporal decay assumptions are invalid.
Safety assumptions fail when time is underestimated. If viability persists longer than assumed, risk is misclassified.
Viral viability decays rapidly on surfaces
The governing assumption is that viruses deposited on common indoor materials lose infectivity within a short, predictable time window.
Decay is surface- and condition-dependent
Viral persistence may vary significantly across material type, humidity, temperature, and micro-environmental conditions.
This creates divergence between assumed decay timelines and actual viability duration.
Persistence window under real conditions
The governing variable is not initial contamination but the duration over which infectious viability remains detectable.
- Short persistence → assumption holds
- Extended persistence → assumption fails
What breaks the assumption
Pass: No detectable infectivity beyond the assumed short window (e.g., ≤24 hours).
Fail: Detectable infectivity persists beyond that window on any surface under ordinary conditions.
Time is a variable, not a constant
Surface safety cannot be defined by fixed decay timelines. It must account for variability across materials and environments.
What this does and does not claim
- Does evaluate persistence duration under defined conditions
- Does not define transmission risk
- Does not establish policy or behavioral recommendations
- Does not generalize across all pathogens or environments
A risk is not gone because time has passed—it is gone when viability is gone.
Time-based assumptions are proxies. Only measured loss of viability defines true decay.
Status: Final · Immutable