Development of a Low Cost Miniature Device for High Spatial, Distributed Monitoring of Aerosol Optical Depth for Regional Level Microclimatic Studies

Air pollution becomes severe when air contains small particles, toxic gases, dust and smoke emitted from numerous sources such as vehicles, industries, fires or fumes in harmful amount. Aerosols of highly reflective in nature increases albedo of the earth and thereby cools the surface and thus effectively offsets greenhouse gases warming by about 25-50%; whereas, absorbing type of aerosols absorbs solar radiation hence increases the surface temperature. Absorbing type aerosols are largely present in the urban environment due to presence of relatively larger number of vehicular fleet and subsequent more fossil fuel combustion than in rural area. Excessive inhalation of particulate matter is detrimental to human health as it can lead to asthma, lung cancer and cardiovascular diseases. Thus, it becomes essential to monitor aerosols accurately using affordable device having widespread presence and potential to address the related problematic issues. One of the important parameters in aerosol measurement is aerosol optical depth (AOD). Several instruments and techniques are used to measure AOD such as with satellite and ground based sun-photometry, ground and airborne radiometers and LIDARs which are generally costly and non-portable. Hence, an effort has been made to develop an affordable sun photometer using photo-detectors and light filters which will track the sun automatically and retrieve AOD of that location. Device measurement thus built has been correlated with standard instrument measurement like Microtops Sunphotometer