Application of spectral immission directivity for long-term environmental noise measurements

• A new concept of Spectral Immission Directivity (SID) is presented. • Integration of spatial and spectral data for better noise source identification. • SID reduces reliance on manual processing in noise assessments. Environmental noise pollution is a growing problem, especially in urban areas where multiple noise sources contribute to a complex acoustic environment. Conventional noise measurement techniques often struggle to distinguish individual sources and their contribution to the overall noise level, requiring extensive post-processing. This study introduces spectral immission directivity (SID), an advanced approach that integrates spatial and spectral data to improve the assessment of environmental noise. SID enables the identification of dominant noise sources in real time by capturing both their directional and frequency characteristics. The proposed method has been evaluated through numerical simulations and controlled experiments in an anechoic chamber, demonstrating its ability to distinguish individual noise sources and their spectral contributions with high accuracy. By using directional frequency analysis, SID provides a more detailed representation of the acoustic scene while minimizing the need for manual classification. The results show that SID increases measurement accuracy, especially in environments where multiple sources overlap in terms of operating times and frequency content. The results suggest that SID can be a powerful tool for environmental noise monitoring that complements existing methods, from standardized compliance measurements to classification models and smart urban monitoring networks.