SSPAM: LED-Based Scanning Sun Photometer for Aerosol Monitoring

Aerosols have significant effects on weather, climate, and human health. Sun photometers are one of the ways to monitor aerosol properties. However, these photometers are either too expensive, too bulky, or inaccurate. This developmental research focused on the development of a sun photometer that is cheaper than those on the current market. It used two lab-tested LEDs with over-the-counter hobbyist electronics. The housings and supporting structures consist of 3D printed parts and an outsourced junction box. During data collection, it calculated solar position locally with campaign details it received through the Google Cloud Platform (GCP). It then publishes LED sensor readings to the GCP at the specified intervals. With these readings, a method known as Langley calibration is applied to calibrate the device and obtain Aerosol Optical Depth and the Ångström exponent. The campaign period from February 18 to March 10, 2022 was held in Antipolo, Rizal, and it yielded average correlation values of 85.8% (500nm) and 88.3% (675nm). Furthermore, the device recorded average AOD values of 0.3679 (500nm) and 0.171 (675nm), which signify the high amounts of aerosols present in the atmosphere of Antipolo. Furthermore, Angstrom exponent averaged 2.47, suggesting that these aerosols may be the result of human-made industrial processes and urban pollution. It was proven in this study that it was possible to develop a cheap, accurate, continuous, and effective LED sun photometer