Potential airborne exposure reduction evaluation of first responders to a surrogate radiological aerosol from simulated contaminated litter-bound patients in cold environments after waterless air-based decontamination using a mannequin.

OBJECTIVE

This study evaluated two waterless air-based decontamination methods to reduce residual airborne expo-sure during the disrobing of a litter-bound surrogate patient mannequin exposed to a surrogate radiological aerosol. The mannequin was clothed in United States military extreme cold weather pants and a jacket.

DESIGN

Copper oxide (CuO) powder was applied as a radiological agent surrogate to a litter-bound mannequin dressed in cold weather outer gear (parka and snow pants) representing the contaminated patient. Two dry air personal decontamination treatments were compared to no decontamination.

SETTING

Cold region mass casualty radiological aerosol contamination event.

PARTICIPANTS

Litter-bound mannequin.

INTERVENTIONS: High-efficiency particulate air (HEPA) vacuum and an air-knife method were evaluated, and the results were compared to no decontamination trials, with CuO as the radiological aerosol surrogate.

MAIN OUTCOME MEASURES: Aerosolized CuO was measured with handheld optical particle counters to measure particle size and count airborne particle concentrations during a 1-minute period directly after disrobing the mannequin. The parti-cle size and count concentrations were used to calculate an estimate of aerosol mass concentration posing an inhalational and surface contamination risk to the patients and the attending medical personnel.

RESULTS

Patient disrobing presented the -highest potential airborne exposure. Nonparametric tests indicated that all treatments were significantly -different (p < 0.05). There was an 85 percent average reduction in CuO airborne aerosol us-ing the HEPA vacuum decontamination method compared to the no decontamination trials. However, the air-knife actually increased airborne risk by 305 percent compared to no decontamination.

CONCLUSION

The successful vacuum trials in this research demonstrate possible waterless decontamination treat-ments for cold environments.