The study of size distribution of atmospheric aerosols is an important tool in understanding and managing aerosol effects on health, visibility and climate. The measurements of surface aerosols, both mass-size distribution and mass concentration, were carried out in the campaign mode at Leh (34°09′N, 77°34′E, 3441 m asl), Hanle (32°47′N, 78°58′E, 4517 m asl) and Delhi (28°39′N, 77°13′E, 220 m asl) during July 2003 to examine their variation with altitudinal and anthropogenic activity. A 15 channel portable particle size aerosol spectrometer GRIMM was used for carrying out the experiment. The aerosol spectrometer is equipped with class 3-B laser as the light source and uses a light scattering technology for single particle counts in the range > 0.3 μm to > 20.0 μm. During the period of observation at all three sites, the pattern of total mass concentration was found to be influenced by supermicron range mass concentration. The higher values of aerosol mass concentration observed at Delhi as compared with those observed at Leh and Hanle on all the channels show a large amount of anthropogenic activity taking place around Delhi vis-à-vis the other two sites. It is further observed that the mass-size distribution changes with the change in altitude and anthropogenic activity.