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Aerosol shapes influence light pollution

21. 3. 2023 | 301 visits

Slovak research team demonstrates the importance of atmospheric parameters to resulting night sky brightness in recent study

In order to correctly identify levels of light pollution caused by artificial light at night, monitoring networks are installed globally and many teams rely on their ground-based measurement results. However, as a team from the Slovak Academy of Science has now shown, it is of great importance to include also atmospheric data like aerosol shapes correctly to interpret collected observations properly. The team’s work is now published in the highly prestigious journal ‘Nature Astronomy’ and will help to improve prediction models for night sky brightness in future works for interdisciplinary research areas.

The term "light pollution" describes a pollution of the natural environment caused by artificial light at night. This happens surprisingly easily, for example due to the misorientation of light sources, i.e., when light falls where it is not needed. Excessive illuminance levels or the use of harmful light colors are just as problematic. The result of all this “misuse” of light is large domes of light appearing over urban areas visible up to hundreds of kilometres away. The irradiation of the sky by artificial light sources and the effects on the environment, animals and humans is a topic that not only astronomers have to face.

Globally, researchers try detecting the phenomenon by installing ground-based light monitoring networks, measuring the brightness of the night sky. However, a research team from the Slovak Academy of Sciences now published a study, focusing on the correct interpretation of data from such networks and how atmospheric particles like aerosols could also influence their outcomes. “The motivation came from our very recent results showing that the night sky brightness computed using highly accurate tools for a population of realistically shaped particles systematically differ from what we can obtain from models currently in use,” says Miroslav Kocifaj, head of the research team from the Institute of Construction and Architecture SAS.

To test this hypothesis, the team used a combination of theoretical analysis, numerical modelling and experimentation, analysing a number of size-shape distributions of aerosol particles that naturally occur in nature. By performing a large number of computations, scattering signatures caused by those particles indicated various outcomes due to morphologies. Field experiments validated the findings.

Results of this work led by the Slovak team, are now released in the highly prestigious journal ‘Nature Astronomy’, as Kocifaj underlines their importance: “The interpretation of data harvested using wide-area networks is subject to careful review and some measurements may require remediation. An increase of measured values should not be routinely interpreted in terms of elevated light emissions until the aerosol properties are known or derived from the information about local pollution sources.”

Especially in times of increasing anthropogenic activities, actions against light pollution caused by urban areas will grow in importance for environmental protection. Therefore, the correct interpretation of its current state and future development is crucial. With their work, the SAS team contributed to achieve this goal more accurately for interdisciplinary research efforts in the future.