Analytical note Trace elements in PM 2.5 in Gothenburg, Sweden ☆ Johan Boman a, ⁎, Annemarie Wagner b , Michael J. Gatari c a Department of Chemistry, University of Gothenburg, SE-412 96, Göteborg, Sweden b Department of Applied Physics, Chalmers University of Technology, SE-412 96, Göteborg, Sweden c Institute of Nuclear Science and Technology, University of Nairobi, P. O. Box 30197-00100, Nairobi, Kenya abstract article info Article history: Received 25 September 2009 Accepted 18 March 2010 Available online 27 March 2010 Keywords: TXRF Carcinogenic Respirable particles Anthropogenic Aerosol particles Ambient aerosol particles smaller than 2.5 μm (PM 2.5 ) are getting more and more attention worldwide. While legal focus is mainly on sample mass, the composition of the particles is an important research field gaining increased interest. The interest is not only connected to possible health effects of the elemental content of the particles, but the elemental determination can also add valuable information for source apportionment. Samples were collected during 20 days in November 2007 at the campus of the Chemistry Department, University of Gothenburg, Gothenburg, Sweden. The particles were collected using a cyclone that separates the PM 2.5 particles from the air stream and impacts them on polycarbonate filters. Filters were changed at early afternoon. The samples were analyzed for particulate mass, black carbon (BC) and the elements S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, As, Br, Cd and Pb. Several of the elements were above detection limit in only a few of the samples. Total reflection X-ray fluorescence (TXRF) spectrometer based on the Wobi TXRF module supplied by the International Atom Energy Agency (IAEA) has been used for the determination of most trace elements in the samples. A Graphite Furnace Atomic Absorption Spectrometer (GF-AAS) was used for complementary trace element analysis and a reflectometer was used to analyze black carbon. Before elemental analysis the filters were digested using a microwave digestion system with temperature and pressure control. The results showed a large variation in sample mass, BC and analyzed elemental concentrations. The variation of the different constituents did not show the same pattern. This added to the picture of different sources for different pollutants. The highest S concentration was noted on a day when the air masses were determined to come from the southeast, i.e. Poland and some other Eastern European countries. From the results it can be concluded that more work is needed on the TXRF spectrometer to optimize it for determination of the EU legally regulated elements As, Ni, Pb and Cd. Despite this the study shows that there is no problem in meeting the AAQS limits for Cd and Pb in Gothenburg. © 2010 Elsevier B.V. All rights reserved. 1. Introduction The problems connected with polluted ambient air are well known and have been following the development of human settlements and activities for centuries. Among these pollutants aerosol particles have undergone a continued interest when it comes to ambient air quality standards (AAQS). Originally and still used in some countries, the total mass of all collected particles (TSP) was used as a measure of particulate pollution. As the knowledge of sources of the particles and the health influence of the particles increased the AAQS have changed so that focus is now on inhalable and respirable particles in many regions of the world. Inhalable particles are particles with an aerodynamic diameter smaller than 10 μm (PM 10 ) while the respirable particles are smaller than 2.5 μm (PM 2.5 ). The legal limit of PM 2.5 is enforced although no lower threshold limit of health effects can be seen in epidemiological studies [1]. The legal focus in Europe is nowadays not only on sample mass, but regulations are also coming into force for some of the elemental content in the aerosol particles. In Europe Pb has been regulated, based on EU directive 1999/30/EG, since the beginning of the 21th century and now the ambient air concentrations of As, Ni and Cd are regulated, according to EU directive 2004/107/EC. Table 1 gives the AAQS for particulate mass and the mentioned elements in the European Union. The values for Pb, PM 10 and PM 2.5 are limit values that must not be exceeded, except the daily PM 10 value that can be exceeded 35 days a year (90 percentile). For As, Ni and Cd the values are target values that should be evaluated and averaged during 3 years where measurements are available for such a time period. There are both natural and anthropogenic sources of the newly regulated elements As, Cd and Ni [2]. For As and Cd volcanic eruptions are the major natural sources, while Ni mainly comes from dust and Spectrochimica Acta Part B 65 (2010) 478–482 ☆ This paper was presented at the 13th Conference on Total Reflection X-Ray Fluorescence Analysis and Related Methods (TXRF 2009), held in Gothenborg, Sweden, 15–19 June 2009, and is published in the Special Issue of Spectrochimica Acta Part B, dedicated to that conference. ⁎ Corresponding author. Tel.: + 46 31 786 9009; fax: +46 31 772 3701. E-mail address: johan.boman@chem.gu.se (J. Boman). 0584-8547/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.sab.2010.03.014 Contents lists available at ScienceDirect Spectrochimica Acta Part B journal homepage: www.elsevier.com/locate/sab