1 Department of Environmental Science - Atmospheric chemistry and physics (Atmospheric proceses) (ATPRO), Department of Environmental Science, Science and Technology, Aarhus University2 Department of Bioscience - Arctic Research Centre, Roskilde, Department of Bioscience, Science and Technology, Aarhus University3 Department of Chemistry, Science and Technology, Aarhus University4 Interdisciplinary Nanoscience Center - INANO-Kemi, Langelandsgade, Interdisciplinary Nanoscience Center, Science and Technology, Aarhus University5 Finnish Meteorological Institute - FMI6 Department of Physics, Lund University7 University of Lund, Lund8 Department of Engineering - Air Quality Engineering, Department of Engineering, Science and Technology, Aarhus University9 Department of Physics - Lund University10 Department of Environmental Science - Atmospheric chemistry and physics (Atmospheric proceses) (ATPRO), Department of Environmental Science, Science and Technology, Aarhus University11 Department of Engineering - Air Quality Engineering, Department of Engineering, Science and Technology, Aarhus University12 Department of Chemistry, Science and Technology, Aarhus University
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 Hovsore, 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 gm(-3) by mass. The corresponding daily average values were 170 cm-3 and 0.023 gm-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.
Atmospheric Chemistry and Physics, 2014, Vol 14, p. 8255-8267
DIESEL-ENGINE EMISSIONS CLIMATE TRAJECTORIES EVOLUTION EXHAUST SYSTEM MATTER