A study to characterize the influence of outdoor SPM and associated metals on indoor environment in Delhi.

In order to understand the influence of outdoor SPM and its associated metals on indoor environment, a study was carried out for 24 residential, sensitive, commercial and heavy traffic sites in Delhi. In the first phase, the samplings of SPM were conducted simultaneously indoors and outdoors at a reference site during February to March 2000 and later at all other sites from February to July 2001. Atomic Absorption Spectrometry (AAS) was used to determine the heavy metal composition of SPM, analyses of Ca, Mg, Cu, Cd, Pb, Cr, Mn, Fe and Ni were done. It is observed that, depending upon the nature of the site, the outdoor SPM concentrations affect the indoor SPM concentrations in varying degrees. In case of metals such as Cu, Cr, Cd and Ni, very good correlation between the indoor and outdoor concentrations was observed irrespective of the nature of the site. The correlation between indoor and outdoor for Mg, Fe, Mn and Pb depends upon the nature of the site. No correlation was observed between indoor and outdoor Ca at any of the chosen sites.