Advancing shipping NOx pollution estimation through a satellite-based approach.

Estimating shipping nitrogen oxides (NOx) emissions and their associated ambient NO2 impacts is a complex and time-consuming task. In this study, a satellite-based ship pollution estimation model (SAT-SHIP) is developed to estimate regional shipping NOx emissions and their contribution to ambient NO2 concentrations in China. Unlike the traditional bottom-up approach, SAT-SHIP employs satellite observations with varying wind patterns to improve the top-down emission inversion methods for individual sectors amidst irregular emission plume signals. Through SAT-SHIP, shipping NOx emissions for 17 ports in China are estimated. The results show that SAT-SHIP performed comparably with the bottom-up approach, with an R2 value of 0.8. Additionally, SAT-SHIP reveals that the shipping sector in port areas contributes ∼21 and 11% to NO2 concentrations in the Yangtze River Delta and Pearl River Delta areas of China, respectively, which is consistent with the results from chemical transportation model simulations. This approach has practical implications for policymakers seeking to identify pollution sources and develop effective strategies to mitigate air pollution.

Evaluation of Methane Emissions Originating from LNG Ships Based on the Measurements at a Remote Marine Station.

We analyzed pollution plumes originating from ships using liquefied natural gas (LNG) as a fuel. Measurements were performed at a station located on the Utö island in the Baltic Sea during 2015-2021 when vessels passed the station along an adjacent shipping lane and the wind direction allowed the measurements. The ratio of the measured concentration peaks ΔCH4/ΔCO2 ranged from 1% to 9% and from 0.1% to 0.5% for low and high pressure dual fuel engines, respectively. The ratio of the measured concentration peaks of ΔNOx/ΔCO2 varied between 0.5‰ and 8.7‰, which was not explained by engine type. The results were consistent with previously measured on-board or test-bed values for the corresponding ratios of emissions. While the methane emissions from high pressure dual fuel engines were found to fulfill the goal of reducing the climatic impacts of shipping, the emissions originating from low pressure dual fuel engines were found to be substantially high, with a potential for increased climatic impacts compared with using traditional marine fuels. Taking only the global warming potential into account, we can suggest a limit value for the methane emissions; the ratio of the emissions ΔCH4/ΔCO2 originating from LNG powered ships should not exceed 1.4%.

Analysis of energy efficiencies of in-port ferries and island passenger-ships and improvement policies to reduce CO2 emissions.

This study focuses on estimating CO2 emissions and analysing energy efficiencies using the Energy Efficiency Operational Index (EEOI) for ferries sailing within an urban port of Taiwan and passenger-ships operating on island routes surrounding Taiwan. A comparative analysis of energy efficiency parameters showed that hybrid diesel-electric ferries had a 12% improved efficiency compared to the traditional full-diesel ferries, while high-speed passenger ships had up to 79% lower efficiency than medium-speed passenger ships. Some potential policies for reducing CO2 emissions from in-port ferries and island passenger-ships are presented based on these results. The estimated CO2 emissions from in-port ferries sailing within the urban port could be reduced by 10% when employing hybrid diesel-electric ferries instead of traditional full-diesel ferries. Emissions from island passenger-ships operating on island routes could be reduced by 11-26% through utilising small medium-speed passenger ships instead of small high-speed passenger ships and large passenger ships.

Ambient marine shipping emissions determined by vessel operation mode along the East China Sea.

Marine shipping emissions exert important air quality and climate impacts. This study characterized the ambient pollutants predominant by emissions from a variety of marine vessel types near the mid-latitude East China Sea. Two discernible primary shipping emissions were identified by factorization analysis on detailed mass spectra of organic aerosol (OA), as emissions in maneuvering and cruise, highly linked with NOx (and less oxidized OA, black carbon, BC) or CO (and more oxidized OA), respectively. Using radio-recorded quantities and activities of 3566 vessels mixed with slow and high-speed diesel engines, we found emission of NOx or BC per vessel was positively correlated with vessel speed, while CO emission peaked at moderate speed. The approach here based on vessel operation mode directly linked the vessel activities to ambient concentrations of pollutants from marine shipping emission, and may synthesize the complex vessel types in shipping emission inventory.

Air quality changes after Hong Kong shipping emission policy: An accountability study.

BACKGROUND: On July 1st, 2015, Hong Kong became the first city in Asia to implement a policy regulating sulfur dioxide (SO2) in shipping emissions. We conducted an accountability study assessing the improvement in ambient air quality and estimating the effect on health outcomes of the policy. METHOD: We used interrupted time series (ITS) with segmented regression to identify any change in ambient concentrations of SO2 in contrast to other ambient pollutants (particulate matter <10 µm in diameter (PM10), nitrogen dioxide (NO2) and ozone (O3)) at 10 monitoring stations in Hong Kong from 2010 to 2017. We validated these findings using cumulative sum control (CUSUM) charts. We used a validated risk assessment model to estimate effects of changes in air quality on death for natural causes, cardiovascular and respiratory diseases. RESULTS: Mean monthly concentrations of SO2 fell abruptly at the monitoring station closest to the main shipping port (Kwai Chung (KC)) by -10.0 µgm3 p-value = 0.0004, but not elsewhere. No such changes were evident for the other pollutants (PM10, NO2, O3). CUSUM charts confirmed a change in July 2015. Estimated deaths avoided per year as a result of the policy were 379, 72, 30 for all natural causes, respiratory and cardiovascular diseases respectively. CONCLUSION: Implementation of the shipping emission policy in Hong Kong successfully reduced ambient SO2, with the potential to reduce mortality. However, to gain full benefits, restrictions on shipping emissions need to be implemented throughout the region.

Shipping pollution emission associated with increased cardiovascular mortality: A time series study in Guangzhou, China.

Substantial evidence has linked short-term exposure to ambient fine particulate matter (PM2.5) with increased cardiovascular mortality, however, the specific chemical constituent and emission source responsible for this effect remained largely unclear. A time series Poisson model was employed to quantify the association of cardiovascular mortality with two sets of shipping pollution emission: nickel (Ni), vanadium (V) (the indices of shipping emission) and estimated shipping emission using a source apportionment approach in Guangzhou, China in 2014. We observed that Ni, V, and estimated shipping emission in PM2.5 were associated with increased cardiovascular mortality, an inter-quartile range (IQR) increase in lag2 Ni was associated with 4.60% (95% CI: 0.14%, 9.26%) increase in overall cardiovascular mortality, and 13.35% (95% CI: 5.54%, 21.75%) increase in cerebrovascular mortality; each IQR increase of lag1 V was correlated with 6.01% (95% CI: 1.83%, 10.37%) increase in overall cardiovascular mortality, and 11.02% (95% CI: 3.15%, 19.49%) increase in cerebrovascular mortality; and each IQR increase in lag1 shipping emission was associated with 5.55% (95% CI: 0.78%, 10.54%) increase in overall cardiovascular mortality, and 10.39% (95% CI: 1.43%, 20.14%) increase in cerebrovascular mortality. The results remained robust to adjustment for PM2.5 mass and gaseous air pollutants. This study suggests that shipping emission is an important detrimental factor of cardiovascular mortality, and should be emphasized in air pollution control and management in order to protect the public health in Guangzhou, China.