In-Use Passenger Vessel Emission Rates of Black Carbon and Nitrogen Oxides

Abstract

This study quantified emission factors of black carbon (BC) and nitrogen oxides (NO x ) from 21 engines on in-use excursion vessels and ferries operating in California’s San Francisco Bay, including EPA uncertified and Tier 1–4 engines and across engine operating modes. On average, ∼60 fuel-based emission factors per engine were measured using a novel combination of exhaust plume capture combined with GPS location and speed data that can be more readily deployed than common portable emissions measurement systems. BC and NO x emission factors (g kg–1) were lowest and least variable during fast cruising and highest during maneuvering and docked operation. Selective catalytic reduction (SCR) reduced NO x emissions by ∼80% when functional. However, elevated NO x emissions that exceeded corresponding exhaust standards were measured on most Tier 3 and Tier 4 engines sampled, which can be attributed to inactive SCR during frequent low engine load operation. In contrast, BC emissions exceeded the PM emission standard for only one engine, and SCR systems employed as a NO x reduction technology also reduced emitted BC. Using these measured emission factors to compare commuting options, we show that the CO2-equivalent emissions per passenger-kilometer are comparable when commuting by car and ferry, but BC and NO x emissions can be several to more than ten times larger when commuting by ferry.

Measurement report: Inland ship emissions and their contribution to NOx and ultrafine particle concentrations at the Rhine

“…For seagoing vessels E PM values ranging from 2 to 3.3 g kg −1 are very similar to our results, whereas E PNC was 2 to 7 times larger (Petzold et al, 2008;Jonsson et al, 2011;Lack and Corbett, 2012;Diesch et al, 2013;Beecken et al, 2014;Celik et al, 2020), probably due to the different fuel composition including the abovementioned higher sulfur content. The BC emission factor derived in this study (E BC = 0.5 ± 0.3 g kg −1 ) is in the upper range of values reported for seagoing ships (Petzold et al, 2008;Diesch et al, 2013;Buffaloe et al, 2014;Jiang et al, 2018;Celik et al, 2020;Schlaerth et al, 2021;Sugrue et al, 2022), although there is a large variability in the literature depending on ship type, engine type, engine load, fuel and operating conditions.…”

“…In general, NO x emission factors derived for inland vessels are lower than the range of 53-68 g kg −1 observed for seagoing vessels (Diesch et al, 2013;Beecken et al, 2014;Kattner, 2019). However, considerably lower values can be observed for marine ships operating in emission control areas and vessels equipped with SCR technology (Sugrue et al, 2022). The NO 2 emission factor of 2.9 ± 2.5 g kg −1 (Fig.…”

“…3 where ship plumes are clearly visible as distinct spikes of various magnitudes and shapes and a drop in O 3 . Applied to marine engines SCR and DPF were found to efficiently reduce NO x and PM emissions by up to 90 % (Nuszkowski et al, 2009;Gysel et al, 2016;Sugrue et al, 2022). At RIV, emission plumes had more time to chemically react in the atmosphere before reaching the sampling inlet.…”

“…This could indicate that real-world particle emissions might not be as efficiently reduced as under test bench conditions. Potential reasons for this are malfunctions and unfavorable operating conditions, e.g., a low engine load (Gysel et al, 2016;Sugrue et al, 2022). However, we have to keep in mind the relatively large uncertainty arising from the estimate for the particle density (Sect.…”

Review of black carbon emission factors from different anthropogenic sources

“…in the recent study of Schlaerth et al (2021), the BC EFs of 0.56 ± 0.86 g kg fuel −1 (passenger boats), 0.64 ± 0.29 g kg fuel −1 (tugboats with loads), 0.48 ± 0.67 g kg fuel −1 (tugboats without loads), 0.36 ± 1.2 g kg fuel −1 (fishing boats) were reported. In the study of Sugrue et al (2022) for the BC emissions of in-use excursion vessels and ferries, the modeweighted mean BC EF values for each engine tier varied from 0.05 g kg fuel −1 (Tier 4, active SCR) to 0.68 g kg fuel −1 (Tier 0).…”