Optical network for monitoring of environmental pollution

The interaction of light with particles and gases can be detected by two processes, namely, scattering and absorption which together is termed as extinction. It is usually responsible for the phenomenon of haze, visibility, air quality etc. An important multidisciplinary approach, involving a comprehensive optical remote sensing system for environmental monitoring of megacities, alongwith several supporting environmental and health surveys is being developed in Pune. This unique observational programme essentially covers a wide spectrum between biological and physical sciences, for monitoring of air pollution through a network of meteorological stations around the twin city of Pune. Each monitoring system in the network employs the Sun and a tunable Argon-ion laser as light sources during daytime and nighttime, respectively. An array of photometers equipped with real-time detection, data acquisition and processing systems, distributed at suitable locations spread over the Pune city, will form the network of receivers. Furthermore, each station will be equipped with additional sensors for monitoring of surface-level meteorological parameters. The physico-chemical characteristics of the regions between the central station where the optical sensor is installed, and network receivers would be different in different directions and could be inferred from the differences in signal strength received by the photometers in the network. The supporting meteorological parameters would be used to understand the dynamics of dispersal for different pollutants. The details of the experiment and data retrieval procedures to obtain aerosol and gaseous optical depths (indicator of air pollution level or air quality over the place) are presented in this paper. The potentiality of the above optical network in the context of nation-wide monitoring of air pollution is highlighted