Air quality regulations for particulate matter (PM) with an aerodynamic diameter of less than 10 and 2.5 micrometers (PM10 and PM2.5, respectively), ozone (O₃), regional haze, and hazardous air pollutants (HAP) require states and regional planning organizations to prepare inventories for emissions that directly or indirectly contribute to ambient pollutant levels. In most populated areas, emissions from diesel engines are believed to account for large fractions of nitrogen oxides (NOx), PM10, PM2.5, black carbon (BC), and toxic materials. Due to their reliability and fuel economy, diesel engines have become the preferred power source for many activities at Department of Defense (DoD) facilities. Emissions from these activities are not well understood, making it difficult for environmental staff on military installations to provide information needed for state and regional planning. Quantification of PM, NOx, sulfur dioxide (SO₂), volatile organic compounds (VOC), and other chemicals from diesels in military use is needed to develop effective policies that will achieve current and future air quality standards.

The primary objective of this project was to develop source-, use-, and fuel-specific emission estimates for representative DoD mobile and stationary diesel equipment, most of which is not used extensively on paved public roadways. These estimates must meet the minimum requirements of the Consolidated Emissions Reporting (CER) rule for emission rates of carbon monoxide (CO), NOx, VOC, PM10, PM2.5, SO₂, and ammonia (NH₃). A second objective was to develop, test, and apply new methods for quantifying non-road emissions that more efficiently and realistically represent actual operations as compared to engine dynamometer certification tests. The final objective was to integrate these results into U.S. Environmental Protection Agency non-road emissions and source profile software, then create an emissions modeling system that permits rapid and efficient estimates to be made for military installations.

The project assembled information about in-use mobile and stationary sources and their activity. Instrumentation for measuring emissions from these sources was evaluated and adapted for real-world testing. Instruments were referenced to an existing mobile heavy-duty diesel (HDD) laboratory that is traceable to the California Air Resources Board (CARB) heavy-duty certification system. On-board and off-board (i.e., in-plume and remote sensing) instrumentation were used to quantify emissions that are typical of duty cycles. Emission factors were developed for integration into existing emissions and air quality models for assessment of DoD contributions to air pollution inventories.

The project resulted in a substantial increase in the number of PM2.5 source profiles with organic speciation, and 25 of these valid individual profiles and composite profiles are being submitted to EPA’s SPECIATE source profile software.  Though emission factors derived from the study were limited, they still make a substantial addition to the available information on emissions from non-road diesel engines, especially those used for military applications. Electronic data files were created that can be pasted into EPA’s NONROAD emissions model that can be used to better estimate base emissions than would be available using the default emission factors.

This project provided the DoD with new emission measurement technologies and improved emission inventories to assess progress in improving air quality and meeting national air quality standards and visibility goals.