Relationships between Indoor and Outdoor Air Quality in Delhi

Abstract

The relationship between indoor and outdoor airborne particles was investigated for 24 residential, sensitive, commercial and heavy traffic sites in Delhi, India. Sampling of suspended particulate matter (SPM) was first conducted simultaneously indoors and outdoors at the reference site during February to March 2000, and later at all the sites during February to July 2001. In order to evaluate the heavy metal composition of the SPM, analyses of Mg, Ca, Cu, Cd, Pb, Cr, Mn, Fe and Ni were done by atomic absorption spectrometry (AAS). It was found that the outdoor SPM concentrations do indeed affect the indoor SPM concentrations in varying degrees depending upon the nature of the site. In case of metals 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.