Compliance and port air quality features with respect to ship fuel switching regulation: a field observation campaign, SEISO-Bohai

Abstract

Abstract. Since 1 January 2017, ships berthed at the core ports of three designated “domestic emission control areas” (DECAs) in China should be using fuel with a sulfur content less than or equal to 0.5 %. In order to evaluate the impacts of fuel switching, a measurement campaign (SEISO-Bohai) was conducted from 28 December 2016 to 15 January 2017 at Jingtang Harbor, an area within the seventh busiest port in the world. This campaign included meteorological monitoring, pollutant monitoring, aerosol sampling and fuel sampling. During the campaign, 16 ship plumes were captured by the on-shore measurement site, and 4 plumes indicated the usage of high-SF (SF refers to the sulfur content of marine fuels). The average reduction of the mean ΔNOx∕ΔSO2 ratio from high-sulfur plumes (3.26) before 1 January to low-sulfur plumes (12.97) after 1 January shows a direct SO2 emission reduction of 75 %, consistent with the sulfur content reduction (79 %). The average concentrations of PM2.5 (particulate matter with a diameter less than 2.5 µm), NOx, SO2, O3 and CO during campaign were 147.85 µg m−3, 146.93, 21.91, 29.68 ppb and 2.21 ppm, respectively, among which NOx reached a maximum hourly concentration of 692.6 ppb, and SO2 reached a maximum hourly concentration of 165.5 ppb. The mean concentrations of carbonaceous and dominant ionic species in particles were 6.52 (EC – elemental carbon), 23.10 (OC – organic carbon), 22.04 (SO42-), 25.95 (NO3-) and 13.55 (NH4+) µg m−3. Although the carbonaceous species in particles were not significantly affected by fuel switching, the gas and particle pollutants in the ambient air exhibited clear and effective improvements due to the implementation of low-sulfur fuel. Comparison with the prevailing atmospheric conditions and a wind map of SO2 variation concluded a prompt SO2 reduction of 70 % in ambient air after fuel switching. Given the high humidity at the study site, this SO2 reduction will abate the concentration of secondary aerosols and improve the acidity of particulate matter. Based on the enrichment factors of elements in PM2.5, vanadium was identified as a marker of residual fuel ship emissions, decreasing significantly by 97.1 % from 309.9 ng m−3 before fuel switching to 9.1 ng m−3 after regulation, which indicated a crucial improvement due to the implementation of low-sulfur fuels. Ship emissions were proven to be significantly influential both directly and indirectly on the port environment and the coastal areas around Bohai Bay, where the population density reaches over 650 people per square kilometer. The results from this study report the positive impact of fuel switching on the air quality in the study region and indicate a new method for identifying the ship fuel type used by vessels in the area.

Measurement of SO2 and NO2 in Ship Plumes Using Rotary Unmanned Aerial System

“…Nevertheless, it can be seen that the UAS presented in this study can provide an active, close-range, low-cost, and accurate measurement approach for monitoring ship emissions in real time. Our measurement results are consistent with those reported in previous studies [4,6,15], which also found that SO 2 /NO 2 ratios can be used, to a certain degree, to ascertain the sulfur content of ship fuel.…”

“…In terms of monitoring methods for FSC, the SO 2 /CO 2 ratio in a ship's plume is widely used as an indicator of FSC [6,7,14]. However, the concentration of CO 2 is often excluded from atmospheric environmental monitoring (e.g., China's national standard GB 3095-2012) [15]. Meanwhile, the SO 2 /NO 2 ratio has been used in optical remote sensing to distinguishing the FSC of a ship [4,6].…”

“…Meanwhile, the SO 2 /NO 2 ratio has been used in optical remote sensing to distinguishing the FSC of a ship [4,6]. There are two main ways to measure ship emissions: Land-based measurement [11][12][13][14][15][16][17] and airborne-based measurement [6,7,10,12,13]. For instance, Beecken et al [13] carried out measurements of SO 2 , NO x , and particulate matter in the Gulf of Finland and Neva Bay area during two campaigns in August/September 2011 and June/July 2012.…”

Surveillance of SO<sub>2</sub> and NO<sub>2</sub> from ship emissions by MAX-DOAS measurements and the implications regarding fuel sulfur content compliance

“…Nevertheless, the slope of different vessels varied greatly from 0.28 to 2.90, indicating the diversity of the SO 2 emission intensity in the ship plumes. In general, SO 2 emissions are directly related to the fuel sulfur content and engine operation status of the ships, according to the emission model estimation, e.g., the power, activity time and the speed of ship (Fan et al, 2016;Zhang et al, 2019). Outbound vessels usually leave the shore slowly with the help of tugboats, and then speed up when sailing into the sea.…”

“…Port cities are most affected by ship pollution, followed by cities along rivers. For example, ship-emitted SO 2 and NO x were shown to contribute 12.4 % and 11.6 % of the total emissions of the whole city of Shanghai in 2012, respectively, while up to 64 % of primary PM 2.5 has been attributed to ships at Shanghai Port; this pollution can then also be transported to inland regions (Fan et al, 2016;Zhao et al, 2013).…”