Regional evaluation of particulate matter composition in an Atlantic coastal area (Cantabria region, northern Spain): Spatial variations in different urban and rural environments A. Arruti ⁎, I. Fernández-Olmo, A. Irabien Universidad de Cantabria, Dep. Ingeniería Química y Química Inorgánica, Avda. Los Castros s/n, 39005 Santander (Cantabria), Spain article info abstract Article history: Received 6 October 2010 Received in revised form 18 January 2011 Accepted 3 March 2011 The aim of this study was to determine the major components (Na, Ca, K, Mg, Fe, Al, NH 4 + , SO 4 2- , NO 3 - , Cl - and TC) and trace-metal levels (As, Ni, Cd, Pb, Ti, V, Cr, Mn, Cu, Mo, Rh and Hg) in PM 10 and PM 2.5 at an Atlantic coastal city (Santander, Cantabria region, Northern Spain). Additional samples were collected in other urban sites of the Cantabria region to assess the metal content found in different urban environments within the region. To control for the mass attributed to inland regional background particulate matter, samples were also collected in Los Tojos village. The spatial variability of the major PM components shows that PM origins are different at inland and coastal sites. In the coastal city of Santander, the most important contributors are (i) the marine aerosol and (ii) the secondary inorganic aerosol (SIA) and the total carbon (TC) in PM 10 and PM 2.5 , respectively. Additionally, the influence of the coastal location on the ionic balance of PM is also studied. The trace metal spatial variability is studied using the coefficient of divergence (COD), which shows that the levels of trace metals at the three studied urban sites are mainly influenced by local emission sources. The main local tracers are identified as follows: Mn in the Santander area; Mo, Cr and Pb at Reinosa; and Ni and V at Castro Urdiales. A more detailed source apportionment study of the local trace metals at Santander is conducted by Principal Component Analysis (PCA) and Positive Matrix Factorisation (PMF); these two receptor models report complementary information. From these statistical analyses, the identified sources of trace metals in PM 10 are urban background sources, industrial sources and traffic. The industrial factor was dominated by Mn, Cu and Pb, which are trace metals used in steel production and manganese-ferroalloy production plant. With respect to PM 2.5 , the identified emission sources of trace metals are combustion processes as well as traffic and industrial sources. © 2011 Elsevier B.V. All rights reserved. Keywords: Trace elements Major components PM 10 PM 2.5 Principal Component Analysis Positive Matrix Factorisation 1. Introduction Particulate matter (PM) is an air pollutant that consists of a complex mixture of substances suspended in the atmosphere. Compared to other atmospheric pollutants, PM is relatively complex to characterise because of its multi-component chemical composition and because of the large range in particle size (Van Dingenen et al., 2004). The chemical composition of PM may vary with regard to its major emission sources; there are also chemical reactions in the atmosphere that can affect PM composition. PM composition also depends on atmospheric circulation, which influences the dispersion, transport and stagnation of pollutants (Pey et al., 2009). In coastal areas, aerosol properties are significantly different from those observed in inland continental locations. Thus, at coastal sites (over either land or ocean), the aerosols exhibit complex physical properties due to the interaction of the continental and marine air masses (Niranjan et al., 2005). Atmospheric Research 101 (2011) 280–293 ⁎ Corresponding author. Tel.:+34 942201579; fax: + 34 942201591. E-mail address: arrutia@unican.es (A. Arruti). 0169-8095/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.atmosres.2011.03.001 Contents lists available at ScienceDirect Atmospheric Research journal homepage: www.elsevier.com/locate/atmos