Abstract
Abstract. Particles in the atmosphere are of concern due to their toxic properties and effects on climate. In coastal areas, ship emissions can be a significant anthropogenic source. In this study we investigated the contribution from ship emissions to the total particle number and mass concentrations at a remote location. We studied the particle number concentration (12 to 490 nm in diameter), the mass concentration (12 to 150 nm in diameter) and number and volume size distribution of aerosol particles in ship plumes for a period of 4.5 months at Høvsøre, a coastal site on the western coast of Jutland in Denmark. During episodes of western winds, the site is about 50 km downwind of a major shipping lane and the plumes are approximately 1 hour old when they arrive at the site. We have used a sliding percentile-based method for separating the plumes from the measured background values and to calculate the ship plume contribution to the total particle number and PM0.15 mass concentration (mass of particles below 150 nm in diameter, converted from volume assuming sphericity) at the site. The method is not limited to particle number or volume concentration, but can also be used for different chemical species in both particle and gas phase. The total number of analyzed ship plumes was 726, covering on average 19% of the time when air masses were arriving at the site over the shipping lane. During the periods when plumes were present, the particle concentration exceeded the background values on average by 790 cm−3 by number and 0.10 μg m−3 by mass. The corresponding daily average values were 170 cm−3 and 0.023 μg m−3, respectively. This means that the ship plumes contributed between 11 and 19% to the particle number concentration and between 9 and 18% to PM0.15 during days when air was arriving over the shipping lane. The estimated annual contribution from ship plumes, where all wind directions were included, was in the range of 5–8% in particle number concentration and 4–8% in PM0.15.
Highlights
Ship emissions and the subsequent chemical reactions in the ship plume lead to formation of ozone and particles, which have adverse health effects through inhalation and deposition in the human respiratory system
It leads to a reduced premature mortality due to particle matter (PM); Partanen et al (2013) estimated a 96 % reduction in mortality due to ship emissions compared to the present day situation
We do not expect any contribution from ships at those areas in our measurements, since a trajectory arriving over the locations of the harbors would most likely not be classified as having arrived from the shipping lane, and the day would not be classified as a ship day and analyzed
Summary
Ship emissions and the subsequent chemical reactions in the ship plume lead to formation of ozone and particles, which have adverse health effects through inhalation and deposition in the human respiratory system. The NOx emissions mainly lead to a reduced methane lifetime over open ocean areas and result in a cooling effect (Bieltvedt Skeie et al, 2009). Emissions of SO2 lead to the formation of sulfate aerosol particles, which generally have a cooling effect on the climate by direct scattering of solar radiation or indirectly, via the formation of cloud droplets (Bieltvedt Skeie et al, 2009). The combined effect of the greenhouse gas emissions and the climate cooling emissions from shipping is a net cooling of the climate at present conditions (Lauer et al, 2009; Bieltvedt Skeie et al, 2009; Fuglestvedt et al, 2009). It leads to a reduced premature mortality due to PM; Partanen et al (2013) estimated a 96 % reduction in mortality due to ship emissions compared to the present day situation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
