Federal facilities are required to report emissions of Toxic Release Inventory (TRI) chemicals under Section 313 of the Environmental Protection Agency’s Emergency Planning and Community Right-to-Know Act (EPCRA). A particularly difficult reporting issue for the Department of Defense (DoD) concerns air emissions resulting from the use of munitions. DoD facilities, specifically testing and training ranges, need reliable air emissions data for TRI chemicals from munitions activities to (1) meet EPCRA reporting requirements and/or (2) demonstrate that emissions are below de minimis concentrations and therefore do not need to be reported.
Currently, emission factors for munitions activities have come primarily from burning and detonating energetic materials under enclosed conditions as well as from theoretical calculations using thermodynamic principles. These activities have provided valuable information for emissions estimation in that they have indicated the types of chemicals that are emitted and they have provided initial estimates of emission factors. However, regulatory agencies often prefer or even require field verification of emission factors. Consequently, field measurements of emissions under realistic outdoor conditions on a range are desired to enhance the credibility of existing emission factors.
The objective of this project was to develop and demonstrate a methodology for measuring emissions of TRI chemicals from DoD munitions activities under realistic conditions and to apply the method to determine emission factors from munitions activities on a range.
To determine an emission factor for a specified chemical, it is necessary to have an estimate of the mass of that chemical released per munitions item or per mass of energetic material in the munition. The mass of the chemical of interest is usually determined from measurement of the chemical’s concentration in the diluted emissions, along with an estimate of the degree to which it has been diluted in the emission cloud. In this project, two types of tests were conducted to characterize emissions from munitions. The Point of Discharge tests were designed to measure the emissions from the firing of a weapon. These tests were conducted in an indoor facility, where the emissions were captured and sampled over a 20-minute period of time. The other type of testing involved measurement of emissions of ordnance items at their Point of Impact. These tests were conducted on an outdoor test range at the Aberdeen Proving Ground.
After laboratory optimization, the instrument package and sampling approach were tested by measuring emissions from the firing of several weapons systems in a large chamber. The approach was then employed to measure emissions of numerous TRI and related chemicals from ten different types of ordnance on a range. Replicate tests were conducted in order to estimate the reproducibility of the emission factors. Some tests were conducted over two different surfaces to assess the effects of soil entrainment on emission factors. The results demonstrated that the majority of the TRI and related chemicals were not found in the emissions from the munitions tested. Emission factors for those chemicals that were observable have been reported.
Using a novel methodology, this project developed an extensive set of data on TRI chemical emissions from a number of munitions that are in widespread use across DoD for testing and training activities. (Project Completed – 2006)