Human epithelial lung cell line, A549, was used to assess the toxicity of copper, nickel, and zinc oxide nanopowders aerosolized by acoustic agitation in laboratory study. Therefore, an in vitro aerosol exposure chamber (AEC) was custom designed and used for direct deposition of NMs from aerosols in the environment to the air-liquid interface of lung cells. Toxicological assessment of NMs by conventional methods in submerged cell culture is not a relevant way to assess inhalation toxicity of NMs because of particle interference with bioassays and changes in particokinetics when dispersed in media. NMs are favored in many applications because of their small size, however, this allows them to easily aerosolize and, subsequently, expose humans via inhalation. Further, a longitudinal study is needed to determine the long-term health consequences of LFF firing emissions exposure.Įxposure to nanomaterials (NMs) is inevitable, requiring robust toxicological assessment to understand potential environmental and human health effects. These results can assist in guiding protective measures to reduce exposure and protect instructor health. Routine monitoring of symptoms, urinary metals, and oxidative stress biomarkers can help identify instructors who are particularly affected by exposures. However, urinary oxidative stress biomarkers and urinary copper measurements were increased in instructors compared to control groups.Ĭonsistent with prior work, this study demonstrates that symptoms still occurred despite exposures below OELs. Biological monitoring showed that lung function was maintained in instructors despite respiratory symptoms. Peak carbon monoxide concentrations were 4–5 times higher at the partially enclosed range compared to the enclosed range and occasionally exceeded the ceiling limit (125 ppm). Copper measured in the breathing zone of instructors, on rare occasions, approached OELs for copper fume (0.1 mg/m ³ ). In general, exposure to instructors was higher at the partially enclosed range compared to the fully enclosed range. Personal breathing zone air monitoring showed exposure to carbon monoxide, ultrafine particulate, and metals. Ventilation measurements demonstrated that airflow velocities at the firing line were highly variable and often outside established standards at both ranges. Instructors reported symptoms more frequently after M4 rifle classes compared to classes firing only the M9 pistol. ![]() ![]() A comprehensive characterization of exposure to instructors was completed, including ventilation system evaluation, personal monitoring, symptom tracking, and biomarker analysis, at both a partially enclosed and fully enclosed range. The disconnect between reported symptoms and exposure limits may be due to a limited understanding of LFF firing byproducts and subsequent health effects. These symptoms have been reported despite measurements determining that instructor exposure does not exceed established occupational exposure limits (OELs). Since the introduction of copper based, lead-free frangible (LFF) ammunition to Air Force small arms firing ranges, instructors have reported symptoms including chest tightness, respiratory irritation, and metallic taste.
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