Elemental analysis of dust trapped in air conditioner filters for the assessment of Lahore city's air quality

The elements Cd, Cr, Cu, Mn, Ni, Pb and Zn were determined in dust samples collected from air conditioner (AC) filters from 15 commercial sites of Lahore using flame atomic absorption spectroscopy (FAAS) while elements such as Al, As, Ba, Br, Ce, Co, Cr, Cs, Eu, Fe, Ga, Hf, Hg, K, La, Lu, Mg, Mn, Na, Nd, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Ti, Th, V, Yb and Zn were determined using instrumental neutron activation analysis (INAA). The results obtained showed that higher amounts of these metals were measured in these dust samples than normally found in soil. This was especially true for Cd, Cu, Pb and Zn. Generally the amounts of Cd, Cr and Mn did not vary throughout the city of Lahore but the amounts of the traffic related elements (Cu and Pb) had more variable ranges of 30-140 and 30-230 mg/kg. The concentrations obtained for Cr, Mn and Zn by INAA were found to be higher than those obtained using FAAS. Analysis of the data showed the digestion procedure employed to be the possible cause for this occurrence. It was also found that Mn was being over-estimated by INAA due to the interference from the Mg peak. (Orig./A.B.)