ABSTRACT
Aerosols, as a group of atmospheric constituents, exhibit wide variability in their physical, chemical, and optical nature. This chapter focuses on various types of techniques and instruments that are deployed to measure aerosol characteristics along with the principles involved. The key atmospheric parameters such as temperature and relative humidity can influence sampling of aerosols. A detector records the scattering intensity from aerosols, which is then processed to obtain the total aerosol number concentration. The most notable uncertainties in aerosol absorption estimates using aethalometer measurements arise because of the changes in filter scattering due to aerosol loading, and underestimation of the measured aethalometer signals with increasing filter load. Size distribution is perhaps the basic aerosol parameter used in determining the other properties of aerosols. In conventional cascade impactors, the aerosol particles settle on a filter paper which can further be used to estimate the mass of aerosols as a function of size.
