Publications
Environmental Science and Technology, June 3, 2009
Abstract: The impact of primary fine particulate matter (PM2.5) from ship emissions within the Southern California Air Basin is quantified by comparing in-stack vanadium (V) and nickel (Ni) measurements from in-use oceangoing vessels (OGVs) with ambient measurements made at 10 monitoring stations throughout Southern California. V and Ni are demonstrated as robust markers for the combustion of heavy fuel oil in OGVs, and ambient measurements of fine particulate V and Ni within Southern California are shown to decrease inversely with increased distance from the ports of Los Angeles and Long Beach (ports). High levels of V and Ni were observed from in-stack emission measurements conducted on the propulsion engines of two different in-use OGVs. The in-stack V and Ni emission rates (g/h) normalized by the V and Ni contents in the fuel tested correlates with the stack total PM emission rates (g/h). The normalized emission rates are used to estimate the primary PM2.5 contributions from OGVs at 10 monitoring locations within Southern California. Primary PM2.5 contributions from OGVs were found to range from 8.8% of the total PM2.5 at the monitoring location closest to the port (West Long Beach) to 1.4% of the total PM2.5 at the monitoring location 80 km inland (Rubidoux). The calculated OGV contributions to ambient PM2.5 measurements at the 10 monitoring sites agree well with estimates developed using an emission inventory based regional model. Results of this analysis will be useful in determining the impacts of primary particulate emissions from OGVs upon worldwide communities downwind of port operations.
Environmental Science and Technology, August 26, 2008
Abstract: This work presents an all-inclusive set of regulated and nonregulated emission factors for the main propulsion engine (ME), auxiliary engine (AE) and an auxiliary boiler on a Suezmax class tanker while operating at sea. The data include criteria pollutants (carbon monoxide, nitrogen oxides, sulfur oxides, and particulate matter), a greenhouse gas (carbon dioxide), the principal speciated hydrocarbons needed for human health risk assessments, and a detailed analysis of the PM into its primary constituents (ions, elements, organic, and elemental carbon). Measurements followed ISO 8178-1 methods with modifications described in the paper. The vessel burned two fuels: a heavy fuel oil in the ME and boiler and a distillate fuel in the AE.The weighted NOx emissions for the ME and AE are 19.87 ± 0.95 and 13.57 ± 0.31 g/kWh, respectively. The weighted PM mass emissions factor is 1.60 ± 0.08 g/kWh for the ME and 0.141 ± 0.005 g/kWh for the AE, with the sulfate content of the PM being the root cause for the difference. For the ME, sulfate with associated water is about 75% of total PM mass, and the organic carbon ranges from 15 to 25% of the PM mass. A deeper analysis showed that the conversion of fuel sulfur to sulfate in the ME ranged from 1.4 to 5%. This article also provides emission factors for selected polycyclic aromatic hydrocarbons, heavy alkanes, carbonyls, light hydrocarbon species, metals, and ions for the ME, AE, and the boiler.
Environmental Science and Technology, February 4, 2009
Authors: Harshit Agrawal CEnv, Shane M. Murphy (1st Author)
Abstract: We report the first joint shipboard and airborne study focused on the chemical composition and water-uptake behavior of particulate ship emissions. The study focuses on emissions from the main propulsion engine of a Post-Panamax class container ship cruising off the central coast of California and burning heavy fuel oil.
Journal of Geophysical Research, December 4, 2010
Abstract: Emission measurements were made for major gases and PM2.5 mass for a post PanaMax Class container vessel operating on heavy fuel oil at sea. Additional measurements were made for PM composition, elemental and organic carbon, select hydrocarbons, including PAHs, carbonyls, and n-alkanes. The testing followed the International Standard Organization protocols for emission measurements and operating test cycle. Results showed the weighted emission factor for NOx and PM2.5 were 19.77 ± 0.28 and 2.40 ± 0.05 g/kWh, respectively. The study provided a rare opportunity to repeat measurements made three years earlier on the same vessel. Emission factors of CO2 and NOx closely matched the earlier values, suggesting a low deterioration factor. Results showed the black carbon emission factor was 0.007 ± 0.001 g/kWh, an important metric for determining the radiative forcing contribution of marine engines.
Atmospheric Environment, July 2008
Abstract: Ocean going vessels are one of the largest uncontrolled sources of pollutants and the emissions data from these sources are scarce. This paper provides the emission measurements of gases, particulate matter (PM), metals, ions, elemental and organic carbon, conducted from the main engine of an ocean going PanaMax class container vessel, at certification cycle and at vessel speed reduction mode, during actual operation at sea. The weighted emission factor (gkW−1h−1) of PM and NOx were 1.64 and 18.2, respectively, for the main engine operating on a 2.05wt% sulfur heavy fuel oil (HFO). The NOx emissions at the vessel speed reduction mode (8% of full load) are 30% higher than at 52% engine power, the normal cruise speed. The composition of PM, from main engine is dominated by sulfate and water bound with sulfate (about 80% of total PM) and organic carbon constitutes about 15% of the PM. Sulfur, vanadium and nickel are the significant elements in the exhaust from the engine running on the HFO. At the point of sampling 3.7–5.0% of the fuel sulfur was converted to sulfate.
Atmospheric Environment, June 2008
Abstract: This paper presents a series of measurements from four on-wing, commercial aircraft engines, including two newer CFM56-7 engines and two earlier CFM56-3 engines. Samples were collected from each engine using a probe positioned behind the exhaust nozzle of the aircraft, chocked on a concrete testing pad. The emission factors for particulate matter mass, elemental and organic carbon, carbonyls, polycyclic aromatic hydrocarbons, n-alkanes, dioxins, metals and ions are reported for four different engine power setting modes. The emissions indices of particulate matter, elemental and organic carbon are highly power dependent for these engines. Particulate matter emission indices (g kg−1 fuel) are found to increase from 1.1E−02 to 2.05E−01 with increase in power from idle to 85%. The elemental carbon to organic carbon varies from 0.5 to 3.8 with change in power from idle to 85%. The carbonyl emissions are dominated by formaldehyde. The emission index of formaldehyde ranges from 2.3E−01 to 4.8E−01 g kg−1 fuel. The distribution of metals depends on the difference in the various engines. The dioxin emissions from the aircraft engines are observed to be below detection limit.
Varalakshmi Jayaram (1st Author), Harshit Agrawal, Environ. Sci. Technol., February 23, 2011
Abstract: Emissions from harbor-craft significantly affect air quality in populated regions near ports and inland waterways. This research measured regulated and unregulated emissions from an in-use EPA Tier 2 marine propulsion engine on a ferry operating in a bay.
M. Yusuf Khan (1st Author), Harshit Agrawal Environmental Science & Technology, September 13, 2012
Abstract: Reducing emissions from ocean-going vessels (OGVs) as they sail near populated areas is a widely recognized goal, and Vessel Speed Reduction (VSR) is one of several strategies that is being adopted by regulators and port authorities. The goal of this research was to measure the emission benefits associated with greenhouse gas and criteria pollutants by operating OGVs at reduced speed. Emissions were measured from one Panamax and one post-Panamax class container vessels as their vessel speed was reduced from cruise to 15 knots or below. VSR to 12 knots yielded carbon dioxide (CO2) and nitrogen oxides (NOx) emissions reductions (in kg/nautical mile (kg/nmi)) of approximately 61% and 56%, respectively, as compared to vessel cruise speed. The mass emission rate (kg/nmi) of PM2.5 was reduced by 69% with VSR to 12 knots alone and by ∼97% when coupled with the use of the marine gas oil (MGO) with 0.00065% sulfur content. Emissions data from vessels while operating at sea are scarce and measurements from this research demonstrated that tidal current is a significant parameter affecting emission factors (EFs) at lower engine loads. Emissions factors at ≤20% loads calculated by methodology adopted by regulatory agencies were found to underestimate PM2.5and NOx by 72% and 51%, respectively, when compared to EFs measured in this study. Total pollutant emitted (TPE) in the emission control area (ECA) was calculated, and emission benefits were estimated as the VSR zone increased from 24 to 200 nmi. TPECO2 and TPEPM2.5estimated for large container vessels showed benefits for CO2 (2–26%) and PM2.5 (4–57%) on reducing speeds from 15 to 12 knots, whereas TPECO2 and TPEPM2.5 for small and medium container vessels were similar at 15 and 12 knots.