Pathogen control system for buildings

BackgroundEnvironmental control systems in buildings are typically designed to maintain occupant comfort while minimizing energy use. However, the significant role of airborne pathogens in respiratory illness transmission has highlighted the imperative to address how these control systems can mitigate infection risk. Traditional CO2-based ventilation control does not necessarily correlate with infectious aerosol presence, limiting its effectiveness for pathogen mitigation. ObjectiveTo develop and evaluate a pathogen control system (PCS) that combines real-time pathogen sensing with in-duct germicidal ultraviolet (GUV) irradiation to reduce infection risk while maintaining energy efficiency and occupant comfort. MethodsWe developed a closed-loop control system using pathogen air quality (PAQ) sensors with hysteretic threshold control (7-20 copies/m3) to dynamically activate GUV systems achieving 99% single-pass inactivation efficiency. System performance was evaluated across four activity scenarios (1.33-750 copies/s generation rates) in a simulated 70 m3 office environment using eight complementary metrics: peak concentration (Cpeak), steady-state concentration (Css), clearance time improvement ({Delta}tclear), time to safety (tsafe), cumulative inhaled dose (Dinh), infection risk probability (Prisk), equivalent clean air rate (ECAi), and energy consumption. ResultsIn talking scenarios, the PCS reduced peak concentration from 40 to 22 copies/m3 (45% reduction), time to safety from 75 to 25 min (67% improvement), cumulative inhaled dose from 1.1x10-2 to 4.4x10-3 copies (60% reduction), and infection risk from 56.07% to 28.88%. In high activity scenarios, peaks decreased from 90 to 45 copies/m3, time to safety from 90 to 30 min, dose from 2.4x10-2 to 8.4x10-3 copies (65% reduction), and risk from 83.93% to 47.83% (43% relative reduction). Baseline active control increased ECAi from 108 to 191 m3/h, with geometric scaling enabling pathways to full ASHRAE 241 compliance (920-3,680 m3/h). System performance was robust across sampling intervals (30-300 s) while achieving 37-52% energy savings through duty-cycle operation. SignificanceThis study provides the first comprehensive quantitative framework for sensor-based pathogen control in building environments. The demonstrated ability to achieve substantial infection risk reduction while maintaining energy efficiency supports the viability of pathogen-responsive building control as an effective intervention for indoor air quality management. Results establish fundamental design principles and performance benchmarks that can inform regulatory guidelines, building codes, and public health recommendations for pathogen control system deployment in the era of healthy buildings. Impact StatementThis research addresses a critical gap in building environmental control by demonstrating how real-time pathogen sensing can enable targeted, energy-efficient disinfection strategies that traditional CO2-based systems cannot achieve. By providing quantitative evidence that sensor-based pathogen control systems can reduce infection risk by 43-67% across realistic occupancy scenarios while maintaining operational efficiency, this work establishes a scientific foundation for next-generation healthy building technologies. The systematic evaluation framework and performance benchmarks developed herein directly support evidence-ng based implementation of pathogen-responsive building control systems, contributing to improved occupant health outcomes and enhanced pandemic preparedness in built environments. These findings are particularly relevant for the Journal of Exposure Science and Environmental Epidemiologys focus on environmental health and exposure assessment, as they provide quantitative tools for evaluating and optimizing indoor air quality interventions that reduce infectious disease transmission risk.