Using a Single Sky Quality Meter for Simplified Light Pollution Changes Analysis Across a Big City

Light pollution involves introducing a large amount of electromagnetic radiation in the visible range (from 380 nm to 760 nm) into the Earth's atmosphere. Its source is all electric lighting installations and applications, such as internal and external lighting or automotive lighting. This phenomenon causes significant adverse effects for the entire environment, e.g., skyglow, limiting the visibility of astronomical objects, disturbances in the circadian rhythms of fauna and flora, or electric energy losses. Light pollution has been studied for at least 40 years. Various ways of measuring it using appropriate sensors and measuring equipment have been developed during this time. This paper presents basic information on light pollution and its measurements. It describes the technical characteristics of the commonly used simple photometer Sky Quality Meter and the problem of using LED lighting. It also describes the results of a measurement experiment in the metropolis of Warsaw, Poland, which made it possible to assess changes in light pollution inexpensively. Measurements and a simplified analysis made it possible to determine that light pollution in the capital of Poland increased by approx. 20% compared to 2015. Using only one low-priced sensor and the presented measurement method can also be successfully employed in other cities.