Characterization of Atmospheric Emission Produced by Live Gun Firing: Test on the M777 155 mm Howitzer

Atmospheric emissions produced by live gun firing of the 155 mm howitzer were characterized during a live firing training exercise in Canadian Forces Base (CFB) Valcartier in January 2007. Sampling was performed continuously for three hours during the exercise during which particles and chemicals accumulated on sampling media. Sixty-nine rounds were fired, each round using four bags of propellant, and an additional 3 rounds were fired, each round using 5 bags of propellant. Established occupational health methods were used to collect and analyze samples for particulate matter, hydrogen cyanide, polycyclic aromatic hydrocarbons (PAHs), dinitrotoluene compounds, benzene, toluene, ethylbenzene and xylene, metals, aldehydes, nitric acid (HNO3), nitric oxide (NO), nitrogen dioxide (NO2), hydrogen sulphide (H2S) and sulphur dioxide (SO2). Two sets of samples were collected, one at approximately 8 m at the left of the gun, and the second one at approximately 22 m in front of the gun muzzle, in the line of fire. Most of the chemicals were not detected during the trial. For both sets of samples, particles were found at concentrations much higher than the recommended environmental standards. The size distribution showed that at least 60% of the particles were below 10 micrometers. These findings suggest that there is a potential risk to health associated with exposure to particles for artillery soldiers. Formaldehyde was also detected at concentrations of 7.1 and 3.6 micrograms/cu m for the left and the front locations, respectively. These findings suggest that there is a need to conduct personal sampling to assess the health risk, if any, to artillery soldiers. For all substances, it is recommended that further investigations of air concentrations be made to properly assess personal exposure. It is also recommended to use more sensitive environmental methods to collect and analyse the samples.
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