Abstract No:
1645
Abstract Type:
Student Poster
Authors:
T Shimata1, J Slagley2
Institutions:
1Air Force Institute of Technology, Wpafb, OH, 2Air Force Institute of Technology (AFIT/ENV), Wright-Patterson AFB, OH
Presenter:
Trenton Shimata
Air Force Institute of Technology
Faculty Advisor:
Dr. Jeremy Slagley, CIH, CSP
Air Force Institute of Technology (AFIT/ENV)
Description:
This research investigated air-driven decontamination strategies aimed at reducing biological contamination and limiting the reaerosolization of particles during clothing removal, specifically in support of ambulatory care in arctic or subzero environments. A life-sized manikin representing a fully mobile Airman was outfitted in standard-issue extreme cold weather gear (parka and pants) and contaminated with 1 μm polystyrene latex (PSL) spheres to simulate anthrax spore exposure. The manikin was then subjected to one of three dry decontamination methods: high-efficiency particulate air (HEPA) vacuuming, a mobile air shower by HalenHardy (MASHH), or no treatment (control).
After contamination, the uniform was removed, and Institute of Occupational Medicine (IOM) inhalable air samplers were positioned at two heights in front of the manikin to capture airborne particles and estimate potential inhalation exposure risks to patients and first responders during the disrobing process. The PSL spheres produced a measurable ultraviolet (UV) fluorescence signal, which allowed airborne particle concentrations to be quantified using UV fluorescence microscopy, employing both manual counting and computer-assisted image analysis. Each decontamination method was tested in ten independent trials, for a total of 30 experiments. Statistical analyses using one-way ANOVA (α = 0.05), followed by Tukey's Honestly Significant Difference (HSD) and the non-parametric Steel–Dwass test, indicated significant differences (p < 0.0001) between the methods and control groups.
On average, HEPA vacuuming reduced airborne PSL concentrations by 98.5%, whereas the mobile air shower achieved a slightly higher reduction of 99.5%. The mobile air shower also exhibited lower variability and a rapid, one-minute cycle time compared to the vacuum procedure, making it highly effective and practical for extreme cold environments. These findings highlight the potential for mobile air shower systems for enhanced personal decontamination that reduce risks to responders and patients during resource-constrained and unique mission operations.
Situation/Problem:
The central research question of this study was: What residual risk remains following dry-air decontamination of a biological surrogate, and how effective are a Mobile Air Shower (MAS) and HEPA vacuum in reducing that risk? Specifically, this work evaluates the ability of these dry decontamination methods to remove polystyrene latex (PSL) spheres used as a surrogate for aerosolized biological agents.
Biological agents dispersed as aerosols pose a significant and persistent threat due to their potential for inhalation exposure and their invisibility to human senses. Events such as the 2001 U.S. anthrax mail attacks demonstrated how aerosolized biological materials can spread undetected and cause severe public health consequences. As a result, rapid and effective decontamination of exposed individuals is critical to reducing secondary exposure risks to patients, responders, and healthcare personnel.
Current personnel decontamination practices rely heavily on water-based methods, which present substantial challenges in extreme cold environments. In subzero conditions, liquid decontamination can freeze, increase the risk of hypothermia, and complicate operations within enclosed shelters. Additionally, contaminated wastewater runoff introduces logistical, environmental, and cleanup burdens, particularly in remote Arctic locations where supply chains, storage capacity, and waste management infrastructure are limited.
Dry decontamination methods offer a potential alternative better suited for cold-region operations, including Cold Region Expeditionary Medical Operations (CREMO). However, limited data exist on their effectiveness and the potential for reaerosolization of contaminants during use. This study addresses that gap by quantifying particle reduction and assessing residual airborne risk following MAS and HEPA vacuum decontamination, providing evidence to inform safer personnel decontamination strategies in extreme cold environments.
Methods:
This experimental study evaluated the effectiveness of two dry decontamination methods, a Mobile Air Shower and a HEPA vacuum, for reducing aerosolized biological agent surrogates on ambulatory patients. Polystyrene latex spheres were used as a surrogate for aerosolized biological agents based on prior validation demonstrating their suitability for simulating anthrax sized particles and for quantifying reaerosolization.
A full scale manikin was dressed in military cold weather parkas and pants to represent personnel operating in extreme cold environments. The experimental protocol was organized into six phases consisting of setup, contamination, decontamination, disrobing, cleanup, and quantification. Polystyrene latex spheres were aerosolized onto the manikin, followed by one of three experimental conditions consisting of no decontamination, Mobile Air Shower decontamination, or HEPA vacuum decontamination.
Pilot testing was conducted to optimize sampling locations and collection durations prior to data collection. IOM inhalable aerosol samplers were positioned at multiple heights to capture airborne particle concentrations representative of breathing zones. Sampling was conducted during and after decontamination to assess potential reaerosolization.
The final dataset consisted of 30 trials, with 10 trials per condition. Each trial followed a standardized procedure and experimental data were recorded in Excel. Particle counts were quantified gravimetrically and compared across decontamination methods using statistical analysis to evaluate differences in airborne particle reduction and residual risk.
Airborne particle count data were analyzed using analysis of variance to evaluate the effects of decontamination method and sampler location on measured concentrations. Least squares means were calculated to assess differences between decontamination conditions while accounting for sampler location. Tukey adjusted post hoc comparisons were used to identify statistically significant differences among methods. Statistical significance was assessed at an alpha level of 0.05. All analyses were performed using JMP Pro 18 software.
Strengths of this methodology include controlled repeatability, use of realistic cold weather clothing, and direct comparison of two dry decontamination methods against a no decontamination baseline. Limitations include the use of a surrogate rather than live biological agents and the controlled laboratory environment, which may not fully represent operational conditions.
Results / Conclusions:
This study evaluated the effectiveness of three decontamination approaches, no decontamination, HEPA vacuum, and Mobile Air Shower, using polystyrene latex spheres as a surrogate for aerosolized biological contamination on cold weather clothing. Across 30 trials, statistical analysis showed that decontamination method was the only factor that significantly influenced airborne particle counts.
The Mobile Air Shower consistently produced the greatest reduction in reaerosolized particles, achieving an average reduction of 99.5 percent relative to no decontamination. The HEPA vacuum also demonstrated substantial effectiveness, with an average reduction of 98.5 percent, though results showed greater variability likely attributable to operator dependent technique. Least squares means and Tukey comparisons confirmed clear separation between both dry decontamination methods and the no decontamination condition, with minimal interaction effects observed.
In addition to particle reduction, the Mobile Air Shower supported faster and more consistent patient throughput compared to manual vacuuming, indicating potential advantages for high tempo operational use.
These findings demonstrate that dry decontamination methods can substantially reduce residual airborne risk from biological surrogates on cold weather gear. The Mobile Air Shower emerged as the most effective and operationally efficient option, providing consistent performance with minimal reliance on operator technique. The HEPA vacuum also reduced contamination and may serve as a viable alternative when space or equipment constraints limit system deployment.
This work fills a critical gap by evaluating dry biological decontamination methods appropriate for freezing and resource constrained environments where liquid based approaches are impractical. The results support the integration of Mobile Air Shower systems into Cold Region Expeditionary Medical Operations and similar emergency response scenarios. Overall, this research reinforces the importance of cold environment compatible decontamination strategies to protect exposed individuals and reduce secondary exposure risks to responders.
Core Competencies:
Biological Hazards
Secondary Core Competencies:
Community Exposure
Risk Management
Choose at least one (1), and up to five, (5) keywords from the following list. These selections will optimize your presentation's search results for attendees.
Aerosol and airborne particulate monitoring
Emergency preparedness and response
Respiratory Protection
Risk assessment and management
Ventilation
Based on the information that will be presented during your proposed session, please indicate the targeted audience practice level: (select one)
Technician: Technician is a job title given to persons who are trained to assist professionals and practitioners with task-specific assignments. Technicians may collect air samples, operate direct-reading instruments, and provide other services based on specific training received and instructions received from professionals and practitioners.
Was this session organized by an AIHA Technical Committee, Special Interest Group, Working Group, Advisory Group or other AIHA project Team?
No
Are worker exposure data and/or results of worker exposure data analysis presented?
No
How will this help advance the science of IH/OH?
This research advances industrial hygiene and occupational health science by providing quantitative evidence on the effectiveness of dry decontamination methods for reducing airborne biological surrogate exposure in cold environments. It expands the current IH evidence base beyond liquid based decontamination by demonstrating that engineering and administrative controls, such as Mobile Air Shower systems and standardized HEPA vacuum procedures, can significantly reduce reaerosolized particulate hazards.
The findings support improved exposure assessment and control strategies for responders, healthcare workers, and support personnel operating in freezing or resource constrained settings. By characterizing residual airborne risk and comparing decontamination methods using inhalable aerosol sampling and statistical analysis, this study informs safer work practices, equipment selection, and emergency response planning. Overall, the work contributes data driven guidance for protecting worker health during biological incidents where traditional decontamination approaches are impractical.
Have you presented this information before?
No
I have read and agree to these guidelines.
Yes