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Shipping emissions were measured in Dunkirk, France. Elevated aerosol extinction coefficients (AEC), nitrogen dioxide (NO2) and sulphur dioxide (SO2) were observed up to 500 m from surface. Formaldehyde (HCHO) did not show an increase every time, which suggests that oxidation of emitted volatile organic compounds (VOCs) took longer than the transport to the observation path and dilution of direct emissions had occurred. Background NO2, HCHO, and SO2 levels were higher when the wind came over land or the surrounding industrial area, indicating that land-based sources contribute significantly; however, clear spikes in NO2 and SO2 were observed whenever ship plumes were sampled. Observations show that the ship emission contribution to pollution is significant, but land-based sources still dominate. The SO2/NO2 ratio was low throughout the campaign, although varying according to the ship type, confirming that the new fuel content regulations are being followed by most ships in this region.

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This work studied the impacts of ship emissions at a high temporal resolution on the real-time concentrations of PM2.5, NO2, and SO2 in urban harbors and coastal sea areas, taking the Yangtze River Delta (YRD) as an example. The WRF-Chem model with 3 nested grids and ship emissions derived from an automatic identification system (AIS) were combined to simulate the air quality. The AIS data showed significant temporal fluctuations in ship emissions, with hourly mean fluxes of approximately 1082.41 ± 444.41 and 593.55 ± 404.95 g/h/km2 near ports and in the channel waters of the YRD, respectively. The monthly mean contributions of shipping emissions reached 80.72% (2.15 ppbv) and 81.79% (8.79 ppbv) to ambient SO2 and NO2 in Ningbo Port, and 10.61% (6.96 µg/m3) to PM2.5 in Shanghai Port, respectively, regions with dense ship traffic. The relative differences in the PM2.5, SO2, and NO2 concentrations modeled using monthly and hourly ship emissions accounted for -10-15%, -10-30%, and - 5-30%, respectively. Compared with cruise- and land-based measurements, the simulations using hourly emissions were in much better agreement with the observations than those using monthly emissions and appropriately captured some air pollutant concentration peaks. Simulations during shipping-related periods with hourly ship emissions improved the normalized mean bias (NMBs) from -43.03%, 301.49%, and 223.02% to -27.28%, 90.45%, and 167.52%, respectively, for PM2.5, SO2, and NO2, highlighting the importance of using ship emissions with a fine temporal resolution. Our study showed that ignoring hourly fluctuations in ship emissions during air quality modeling leads to considerable uncertainties, especially in coastal urban areas and harbors with high ship activities. These results imply that data with a high temporal resolution, such as hourly ship emissions, are necessary to understand the realistic impacts of shipping traffic and to implement more precise control policies to improve coastal air quality.

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BACKGROUND: Knowing the numbers of bacteria in coastal atmospheric air as well as in coastal waters significantly contributes to a better understanding of the processes affecting the health of people who stay temporarily or permanently in areas where the synergistic effect of the atmospheric conditions and the aquatic environment on a human body is particularly strong. MATERIALS AND METHODS: Seawater and air samples were collected from 22 May to 22 July 2018 in the seaside towns of Hel, Puck, Gdynia, Sopot, Gdansk-Brzezno, all located along the Gulf of Gdansk. The number of psychrophilic, mesophilic as well as coliform bacteria and Escherichia coli was determined in both the water and the ambient air samples. In total, 232 seawater and coastal air samples were collected for the study purposes. RESULTS: The study showed a deterioration of coastal waters and atmospheric air in the Gulf of Gdansk which may have resulted from an increase of potentially pathogenic mesophilic bacteria following the emergency discharge of raw sewage from the Gdansk-Wschod wastewater plant. CONCLUSIONS: An increase in the number of coliform bacteria and Escherichia coli in the seawater and in the air across the Gulf of Gdansk is related to the emergency sewage discharge.

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The present study combines high-resolution measurements at various distances from a world-class gigantic petrochemical complex with model simulations to test a method to assess industrial emissions and their effect on local air quality. Due to the complexity in wind conditions which were highly seasonal, the dominant wind flow patterns in the coastal region of interest were classified into three types, namely northeast monsoonal (NEM) flows, southwest monsoonal (SEM) flows and local circulation (LC) based on six years of monitoring data. Sulfur dioxide (SO2) was chosen as an indicative pollutant for prominent industrial emissions. A high-density monitoring network of 12 air-quality stations distributed within a 20-km radius surrounding the petrochemical complex provided hourly measurements of SO2 and wind parameters. The SO2 emissions from major industrial sources registered by the monitoring network were then used to validate model simulations and to illustrate the transport of the SO2 plumes under the three typical wind patterns. It was found that the coupling of observations and modeling was able to successfully explain the transport of the industrial plumes. Although the petrochemical complex was seemingly the only major source to affect local air quality, multiple prominent sources from afar also played a significant role in local air quality. As a result, we found that a more complete and balanced assessment of the local air quality can be achieved only after taking into account the wind characteristics and emission factors of a much larger spatial scale than the initial (20 km by 20 km) study domain.

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