  Aerosols, both natural and anthropogenic, play an important role in the
atmospheric science, by imparting radiative forcing and perturbing the
radiative balance of the Earth atmosphere system as well as by degrading the
environment. To understand the effect of aerosols on our geo/biosphere system,
it is essential to characterize their physical and chemical properties
regionally because of the regional nature of their properties and the short
lifetime. As most of the aerosol sources are of terrestrial origin the
variability of their properties will be very large close to the surface. At
higher altitudes, above the mixing region, and in the free troposphere, the
aerosol characteristics have a more synoptic perspective; would be indicative
of the background level and are useful to understand long-term impacts. Such
systematic measurements of aerosols at high altitudes are practically
non-existing in India. Realising the potential and need for such studies, an
activity has been initiated at Manora Peak, Nainital in the Shivalik Hills of
Central Himalayas at an altitude of $\sim$2 km. The present paper provides the
preliminary results of these aerosol measurements. These daytime measurements
are compared with the existing earlier nighttime measurements.
