The possible influence of volcanic emissions on atmospheric aerosols inthecityofColima,Mexico Javier Miranda a, *, Francisco Zepeda b ,IgnacioGalindo b a Instituto de Fı´sica, Universidad Nacional Auto ´noma de Me ´xico, Apartado Postal 20-364, 01000 Mexico, D.F., Mexico b Centro Universitario de Ciencias del Ambiente, Universidad de Colima, Ave. 25 de Julio 965, Col. Villa San Sebastia ´n, 28045, Colima, Col., Mexico Received 29 March 2002; accepted 10 July 2003 ‘‘Capsule’’: Elemental analyses of PM 15 in the City of Colima, Mexico, were done to identify possible contributions from the Volca´ndeColima, an active volcano. Abstract AnelementalcompositionstudyofatmosphericaerosolsfromtheCityofColima,intheWesternCoastofMexico,ispresented. SamplesofPM 15 –PM 2.5 andPM 2.5 werecollectedwithStackedFilterUnits(SFU)ofthe Davis design,inurbanandruralsites,the latter located between the City of Colima and the Volca ´n de Colima, an active volcano. Elemental analyses were carried out using ParticleInducedX-rayEmission(PIXE).Thegravimetricmassconcentrationsforthefinefractionwereslightlyhigherintheurban site,whilethemeanconcentrationsinthecoarsefractionwereequalwithintheuncertainties.HighClcontentsweredeterminedin thecoarsefraction,afactalsoobservedinemissionsfromthe Volca ´n de Colima byotherauthors.Inadditiontoaverageelemental concentrations,clusteranalysisbasedonelementalcontentswasperformed,withwindspeedanddirectiondata,showingthatthere isanindustrialcontributortoaerosolsNorthoftheurbanarea.Moreover,acontributionfromthevolcanicemissionswasidenti- fiedfromthegroupingofS,Cl,Cu,andZn,elementsassociatedtoparticlesemittedbythe Volca ´n de Colima. # 2003ElsevierLtd.Allrightsreserved. Keywords: Atmosphericaerosols;Volcanicemissions;PIXE;Colimavolcano;CityofColima 1. Introduction Many studies covering several aspects of atmospheric aerosols, aimed to fully characterize them, are con- ductedallaroundtheworld,becausetheyarepollutants thatextendtheirinfluencefromalocaltoaglobalscale. Thisincludeseffectsonhealthandvegetation(Saxenaet al.,1997;Olmoetal.,1999;Spurny,2000;Varricaetal., 2000). Sources of aerosols are either anthropogenic or natural. The first group comprises, for example, indus- try, vehicles, power plants, and man-originated forest fires. In addition, natural sources include soil-derived dust, sea salt, or volcanic emissions. It is possible, in principle, to regulate, and thus reduce, anthropogenic aerosols.Thisisnotthecase,however,forsomenatural sources,suchasvolcanicemissions.Inareaswherethere may be both kinds of sources, it is necessary to study their effects, especially when a characterization of the aerosols is practicable, beyond the simple gravimetric mass measurements. The elemental composition of volcanic emissions has been studied in several works. Among the most com- prehensive efforts is the project ‘‘Research on Atmo- spheric Volcanic Emissions’’, conducted by NASA and other universities in the United States (Friend et al., 1982). Other authors (Buat-Me´nard and Arnold, 1978; Quisefit et al., 1987) studied the particles expelled by MountEtna.Inthesameline, Darzi(1981)andHinkley et al. (1999) published results on the emissions by Mount Kilauea, Hawaii. A characterization of emis- sions from the Mount Redoubt volcano (Alaska) was carried out by Hobbs et al. (1991). The impact of 0269-7491/$ - see front matter # 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0269-7491(03)00265-3 Environmental Pollution 127 (2004) 271–279 www.elsevier.com/locate/envpol * Corresponding author. Tel.: +52-55-5622-5073; fax: +52-55- 5622-5009. E-mail address: miranda@fisica.unam.mx (J. Miranda).