Determinations of Sb and Mo in Cairo’s dust using high-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sample analysis Abdallah A. Shaltout a, b, * , Bernhard Welz c, d , Ivan N.B. Castilho c a Spectroscopy Department, Physics Division, National Research Center, El Behooth Str., 12622 Dokki, Cairo, Egypt b Physics Department, Faculty of Science, Taif University, P.O. Box 888, 21974 Taif, Saudi Arabia c Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil d Instituto Nacional de Ciência e Tecnologia do CNPq e INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA, Brazil highlights  Developed method for solid sampling analysis of Sb and Mo in dust was presented.  The results were obtained from SS-HR-CS AAS.  The pyrolysis and atomization temperatures were optimized.  The average value of Sb is twenty times higher than the international screening level.  Mo content is lower than screening level. article info Article history: Received 2 July 2013 Received in revised form 21 August 2013 Accepted 27 August 2013 Keywords: Air pollution Sb Mo Direct solid sample analysis High-resolution continuum source graphite furnace atomic absorption spectrometry abstract The present work describes the determination of Sb and Mo in dust deposited on tree leaves using direct solid sample analysis. Nineteen air particulate samples were collected from different districts of Cairo and surrounding cities. Since some samples have been taken from places less exposed to the pollution factors, the present study allows the comparison of air quality between high and low polluted areas. High-resolution continuum source graphite furnace atomic absorption spectrometry has been investi- gated, using direct solid sample analysis. The optimum pyrolysis and atomization temperatures for Sb were found to be 800  C and 1900  C, and 1200  C and 2650  C, respectively for Mo. The limits of detection and quantification for both, Sb and Mo, were 15 mgg 1 and 50 ng g 1 , respectively. The characteristic mass at was found to be m 0 ¼ 38 pg for Sb (217.582 nm) and m 0 ¼ 28 pg for Mo (313.259 nm). The results obtained for three certified reference materials of urban particulate matter confirmed the validity of the investigated method. The content of Sb varied between 213  1.3 mgg 1 and 1117  230 mgg 1 with an average of 667  339 mgg 1 . On the other hand, the Mo content varied from 113  2.3 mgg 1 to 361  51 mgg 1 and its average value equals 190  62 mgg 1 . Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Air contamination in Greater Cairo and the surrounded districts is a problem of great interest as it is considered as one of the most polluted megacities around the world (United Nations Environment Programme, 1992). Greater Cairo is about 1000 years old, but parts of the metropolis date back to the time of the Pharaohs. It is the largest city in Africa and the Middle East and it includes Cairo, Giza and Kalubia provinces. The population of the Great Cairo urban agglomeration is more than 20 million. The monthly average temperature ranges from 14  C in January to 29  C in July, but the maximum day temperature can reach 45  C in summer. It was recognized that the agricultural areas around Cairo decreased over the last years due to urban development. At the same time, industrial activities in Greater Cairo increased remark- ably. Therefore, there are different major sources of air pollution, such as mobile sources (cars, trucks etc.), stationary sources (in- dustry, power stations etc.), and open burning sources. This * Corresponding author. Spectroscopy Department, Physics Division, National Research Center, El Behooth Str., 12622 Dokki, Cairo, Egypt. Tel.: þ20 233669974 2101; fax: þ20 233370931. E-mail address: shaltout_a@hotmail.com (A.A. Shaltout). Contents lists available at ScienceDirect Atmospheric Environment journal homepage: www.elsevier.com/locate/atmosenv 1352-2310/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.atmosenv.2013.08.049 Atmospheric Environment 81 (2013) 18e24