High concentration episodes of PM10 in the air over the urbanized coastal zone of the Baltic Sea (Gdynia — Poland) Anita Urszula Lewandowska ⁎, Lucyna Mirosława Falkowska Oceanography Institute, University of Gdańsk, Al. Marszałka J. Piłsudskiego 46, 81-378 Gdynia, Poland article info abstract Article history: Received 10 June 2012 Received in revised form 31 July 2012 Accepted 1 August 2012 During the years 2008–2009, studies were conducted on PM10 in the atmosphere over Gdynia. The basic chemical composition of PM10 aerosols (inorganic species, organic and elemental carbon) was measured during periods of heightened health risk. As the quality of air depends on natural as well as anthropogenic factors, it was important to specify which of these factors prevail under different synoptic conditions and at different times, and which have the greatest influence on human health. In the course of the 24-month research period, the daily PM10 limit value (50 μg·m -3 ) in the coastal zone of the Gulf of Gdansk, was exceeded 25 times. High concentration episodes invariably occurred in the cold months of the year. The first kind of episode was related to sea activity and the highest share of sea salt in aerosols (NaCl=46.5%). A second type of high PM10 concentration occurred at south-eastern advection when secondary aerosols, aging on the way from the source, were carried over Gdynia. In the spring of 2009, as a result of biomass combustion (fires and grass burning) in Ukraine and Southern Russia, the PM10 mass concentration climbed to 117.1 μg·m -3 and was accompanied by substantial increases in nitrogen, sulfur and carbon compounds (reaching 32.5 μg·m -3 , 20.0 μg·m -3 , and 6.0 μg·m -3 , respectively). The third kind of high PM10 concentration was related to local sources, mostly within the communal sector, the harbor area and the transshipment base, and was the consequence of low dispersion of pollution at a wind speed of 1 m·s -1 . At such times there was a rapid increase of carbon compound concentrations (53.8%). Elemental carbon, an air pollution indicator which originates from means of transport, had the highest proportion in such instances, reaching 15.8% of the total PM10 mass concentration. © 2012 Elsevier B.V. All rights reserved. Keywords: Local PM10 Regional PM10 Transboundary PM10 Synoptic conditions Coastal zone 1. Introduction Invisible to the naked eye due to their minute dimensions, aerosol particles remain beyond human areas of interest until the polluted atmosphere detracts from the comfort of living, and the inhaled air poses a health hazard. While regional effects are related to acid rains and increased eutrophication of surface water, in the long run it is aerosols that play the most important role in such continental and global effects as the depletion of atmospheric ozone or climate changes. On a local scale, their emission close to the source has an immediate effect, manifested for example by air pollution which can be oppressive for humans. As a long term effect, aerosols can have influence on a continental or global scale, for example on the depletion of stratospheric ozone or climate changes. A considerable proportion of aerosols consists of non- organic compounds such as sulfates, nitrates, chlorides, sodium and ammonium ions. Aerosols rich in ammonium salts are known for their properties of water absorption in the atmosphere. Depending on air humidity and the proportions in which ammonium sulfate and ammonium nitrate occur, the aerosol properties of reflecting and dispersing solar radiation change. This phenomenon has an influence on the cooling down of the climate thus reducing the effect which, on a global scale, carbon dioxide has on climate warming. On the other hand, aerosol enrichment with elemental carbon, which as with greenhouse gasses has the ability to absorb radiation, can Atmospheric Research 120–121 (2013) 55–67 ⁎ Corresponding author. Tel.: +48 585236837; fax: +48 58 523 66 78. E-mail address: a.lewandowska@ug.edu.pl (A.U. Lewandowska). 0169-8095/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.atmosres.2012.08.002 Contents lists available at SciVerse ScienceDirect Atmospheric Research journal homepage: www.elsevier.com/locate/atmos