Title: Improving Emission Rates Estimates of Commercial Marine Vessels
Institution(s) Represented: University of Houston (James Flynn), Ramboll (Chris Lindhjem), FluxSense (Jerker Samuelsson)
Lead PI: James Flynn
AQRP Project Manager: Vincent Torres
TCEQ Project Liaison: Cody Mclain
Abstract
The Texas Commission on Environmental Quality (TCEQ) relies on emission inventories to shape the State Implementation Plan (SIP), crucial for managing air pollutants such as nitrogen oxides (NOX) and ozone (O3). Recognizing the significance of reliable data, the team of the University of Houston (UH) and Ramboll propose this research project to address the research priority identified by the Air Quality Research Program (AQRP) to improve emission inventories for commercial marine vessels (CMV).
CMV emissions, particularly NOX, constitute a substantial portion of coastal NOX emissions. In the Houston-Galveston-Brazoria nonattainment area, CMVs accounted for approximately 18% of NOX emissions in 2019, with a continued significant contribution expected for years to come. Among different vessel categories, smaller commercial vessels, notably towboats, were responsible for about 42% of CMV NOX emissions in Texas in 2019 (TCEQ, 2023). Towboat and tugboat emissions have greater uncertainty than other CMV categories due to the lack of information on engines and the uncertainties of engine loads and operating parameters. This proposal aims to improve our understanding of commercial marine exhaust emissions, focusing on NOX, volatile organic compounds (VOC), PM2.5, and hydrocarbon speciation. The emphasis on smaller vessels will improve our ability to intercept their exhaust plumes.
Employing the instrumented UH research boat, our approach involves sampling emission plumes from vessels downwind of busy shipping lanes in Galveston Bay. Plumes will be identified by elevated levels of carbon dioxide (CO2), NOX, and other compounds. We expect to sample plumes from hundreds of towboats to meaningfully constrain the emission inventory. Leveraging real-time Automatic Identification System (AIS) transponder data, which reports vessel identification, position, speed, and draft, enhances our ability to connect measured plumes to individual vessels and ascertain engine information.
Emissions rates, derived from the field measurement data, will be compared with EPA expected values for each of the sampled and identified vessel engines. Multiple encounters with the same vessel over the sampling period will provide insights into emission variability. The analysis results have the potential to enhance the accuracy of the commercial marine emission inventory and speciated VOC reactivity. Such improvement can be integrated into various modeling frameworks, including those utilized for SIP modeling that support air quality planning efforts.
Workplan: PENDING UPDATE
Technical Reports: PENDING UPDATE
QAPP: PENDING UPDATE
