title: Characterization of exposure to byproducts from firing lead-free frangible ammunition in an enclosed, ventilated firing range.
abstract: U.S. Air Force small arms firing ranges began using copper-based, lead-free frangible ammunition in the early 2000s due to environmental and health concerns related to the use of lead-based ammunition. Exposure assessments at these firing ranges have routinely detected chemicals and metals in amounts much lower than their mass-based occupational exposure limits, yet, instructors report work-related health concerns including respiratory distress, nausea, and headache. The objective of this study at one firing range was to characterize the aerosol emissions produced by weapons during firing events and evaluate the ventilation system's effectiveness in controlling instructor exposure to these emissions. The ventilation system was assessed by measuring the range static air pressure differential and the air velocity at the firing line. Air flow patterns were near the firing line. Instructor exposure was sampled using a filter-based air sampling method for metals and a wearable, real-time ultrafine particle counter. Area air sampling was simultaneously performed to characterize the particle size distribution, morphology, and composition. In the instructor's breathing zone, the airborne mass concentration of copper was low (range = <1 µg/m3to 16 µg/m3), yet the ultrafine (nanoscale) particle number concentration increased substantially during each firing event. Ultrafine particles contained some copper and were complex in morphology and composition. The ventilation assessment found that the average velocity across all shooting lanes was acceptable compared to the recommended guideline (20% of the ideal 0.38 m/s (75 ft/min). However, uniform, downrange airflow pattern requirements were not met. These results suggest that the mass-based occupational exposure limits, as applied to this environment, may not be protective enough to eliminate health complaints reported by instructors whose full-time job involves training personnel on weapons that fire lead-free frangible ammunition. Using an ultrafine particle counter appears to be an alternative method of assessing ventilation effectiveness in removing ultrafine particulate produced during firing events.
authors.affiliation: a Force Health Branch, United States Air Force School of Aerospace Medicine , Wright-Patterson Air Force Base , Dayton , Ohio.
authors.forename: Christin M
authors.initials: CM
authors.lastname: Grabinski
authors.affiliation: b National Institute for Occupational Safety and Health , Cincinnati , Ohio.
authors.forename: Mark M
authors.initials: MM
authors.lastname: Methner
authors.affiliation: a Force Health Branch, United States Air Force School of Aerospace Medicine , Wright-Patterson Air Force Base , Dayton , Ohio.
authors.forename: Jerimiah M
authors.initials: JM
authors.lastname: Jackson
authors.affiliation: c Human Signatures Branch, Airman Systems Directorate, United States , Wright Patterson Air Force Base , Dayton , Ohio.
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Moore
authors.affiliation: c Human Signatures Branch, Airman Systems Directorate, United States , Wright Patterson Air Force Base , Dayton , Ohio.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Flory
authors.affiliation: d Molecular Bioeffects Branch, Airman Systems Directorate , Wright Patterson Air Force Base , Dayton , Ohio.
authors.forename: Trevor
authors.initials: T
authors.lastname: Tilly
authors.affiliation: d Molecular Bioeffects Branch, Airman Systems Directorate , Wright Patterson Air Force Base , Dayton , Ohio.
authors.forename: Saber M
authors.initials: SM
authors.lastname: Hussain
authors.affiliation: a Force Health Branch, United States Air Force School of Aerospace Medicine , Wright-Patterson Air Force Base , Dayton , Ohio.
authors.forename: Darrin K
authors.initials: DK
authors.lastname: Ott
mesh_terms: D000392:Air Movements; D000395:Air Pollutants, Occupational / Q000032:analysis*; D003300:Copper / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D005389:Firearms; D006801:Humans; D008889:Military Personnel; D053758:Nanoparticles / Q000032:analysis; D016273:Occupational Exposure / Q000032:analysis*; D009820:Ohio; D010316:Particle Size; D014691:Ventilation
chemical_list: D000395:Air Pollutants, Occupational; D003300:Copper
keywords: Direct reading instruments; occupational exposure limits; small arms, ultrafine particles; ventilation; wearable ultrafine particle counters