Abstract— This work presents a compact ultraviolet-C (UV-C) germicidal module with a model-based control architecture that maintains the required antimicrobial dose under varying temperature and humidity. Opposed low-pressure UV-C lamps within a reflective enclosure provide dual-sided, spatially uniform irradiation of thin, planar items such as banknotes. A mechanistic dose model captures lamp output as a function of cold-spot temperature and incorporates humidity-dependent penalties in inactivation efficacy on paper-like substrates, enabling real-time computation of the exposure needed to achieve a user-specified log-reduction target. Embedded sensors measure lamp temperature and ambient relative humidity, and an onboard controller uses these inputs to adapt conveyor speed and dwell time so that the commanded dose is delivered while throughput is maximized and safety interlocks are enforced. Laboratory validation on a circulated Jordanian dinar banknote demonstrated complete elimination of Staphylococcus epidermidis (pre-treatment surface count: 10⁵ CFU; no bacterial growth detected after 72-hour post-treatment incubation), confirming that the delivered dose meets and exceeds the targeted ≥4-log reduction under real-world substrate conditions. Dosimetric modelling across the full environmental operating range (0–60 °C, 0–90% RH) demonstrates robust dose delivery, indicating that the proposed control framework is broadly applicable to high-throughput UVGI decontamination systems.