Effect of atmospheric black carbon aerosols over Delhi

136-139The atmospheric aerosols are the particles of solid or liquid phase that are found dispersed in the atmosphere. Aerosols by scattering andabsorption phenomenon contribute to direct forcing and indirect forcing by formation of cloud condensation nuclei. Black Carbon (BC)aerosols, the optically absorbing carbonaceous aerosols released from the incomplete combustion of almost all the fuels is an importantaerosol constituent. Its diameter is about 0.1 micron. In the present study changes in black carbon aerosols have been presented. Black carbonaerosols show spatial and temporal diurnal variation. BC exhibited highest concentration occurring 0630h to 0930h and again at around 2000htill midnight and low concentration from ~1000h while lowest concentration from 0930 to evening. The annual average BC concentration ofDelhi (January 2006 to December 2006) was 14.75 μg/m3. During winter months (December, January and February) concentration increasesto 25 μg/m3. Black carbon aerosols is about 6 % of RSPM