Analysing Interlinked Frequency Dynamics of the Urban Acoustic Environment.

As sustainable metropolitan regions require more densely built-up areas, a comprehensive understanding of the urban acoustic environment (AE) is needed. However, comprehensive datasets of the urban AE and well-established research methods for the AE are scarce. Datasets of audio recordings tend to be large and require a lot of storage space as well as computationally expensive analyses. Thus, knowledge about the long-term urban AE is limited. In recent years, however, these limitations have been steadily overcome, allowing a more comprehensive analysis of the urban AE. In this respect, the objective of this work is to contribute to a better understanding of the time-frequency domain of the urban AE, analysing automatic audio recordings from nine urban settings over ten months. We compute median power spectra as well as normalised spectrograms for all settings. Additionally, we demonstrate the use of frequency correlation matrices (FCMs) as a novel approach to access large audio datasets. Our results show site-dependent patterns in frequency dynamics. Normalised spectrograms reveal that frequency bins with low power hold relevant information and that the AE changes considerably over a year. We demonstrate that this information can be captured by using FCMs, which also unravel communities of interlinked frequency dynamics for all settings.

Planning for Sustainable Green Urbanism: An Empirical Bottom-Up (Community-Led) Perspective on Green Infrastructure (GI) Indicators in Khyber Pakhtunkhwa (KP), Pakistan.

Rising vulnerability of the urban green infrastructure (UGI) is grabbing global attention, for which inclusive urban landscape and greening policies (ULGP) and frameworks are crucial to support green growth. As such, this research intends to explore the local community's perspective to assemble sustainable UGI indicators for vital taxonomy of the urban green space (UGS) elements, aiming to develop a multi-functional and sustainable UGI-indicator-based framework that is eco-friendly and supports green-resilient cities in Khyber Pakhtunkhwa (KP) province, Pakistan. An in-depth household survey was executed in three KP districts: Charsadda, Peshawar, and Mardan, placing self-administered 192 questionnaires while covering themes around climate change adaptation, urban resilience, and UGI. Relative importance index (RII) and the interquartile range (IQR) methods were set up for data analysis that revealed excellent reliability (α > 0.88) and internal consistency. The results confirmed community-based UGI indicators with a focus on promoting green-energy-saving strategies as e-imp (level 9, RII = 0.915), while other (ten) UGI indicators as important (RII = 0.811-0.894) and (eleven) as moderately important (RII = 0.738-0.792). These UGI indicators were found to be enhanced by UGS elements (RII ≥ 0.70). These findings provide a foundation for urban policy change and the development of a sustainable UGI framework to build an eco-regional paradigm for greener growth.

Impact of the COVID-19 Lockdown Measures on Noise Levels in Urban Areas-A Pre/during Comparison of Long-Term Sound Pressure Measurements in the Ruhr Area, Germany.

BACKGROUND: A major source of noise pollution is traffic. In Germany, the SARS-CoV-2 lockdown caused a substantial decrease in mobility, possibly affecting noise levels. The aim is to analyze the effects of the lockdown measures on noise levels in the densely populated Ruhr Area. We focus on the analysis of noise levels before and during lockdown considering different land use types, weekdays, and time of day. METHODS: We used data from 22 automatic sound devices of the SALVE (Acoustic Quality and Health in Urban Environments) project, running since 2019 in Bochum, Germany. We performed a pre/during lockdown comparison of A-weighted equivalent continuous sound pressure levels. The study period includes five weeks before and five weeks during the SARS-CoV-2 induced administrative lockdown measures starting on 16 March 2020. We stratified our data by land use category (LUC), days of the week, and daytime. RESULTS: We observed highest noise levels pre-lockdown in the 'main street' and 'commercial areas' (68.4 ± 6.7 dB resp. 61.0 ± 8.0 dB), while in 'urban forests' they were lowest (50.9 ± 6.6 dB). A distinct mean overall noise reduction of 5.1 dB took place, with noise reductions occurring in each LUC. However, the magnitude of noise levels differed considerably between the categories. Weakest noise reductions were found in the 'main street' (3.9 dB), and strongest in the 'urban forest', 'green space', and 'residential area' (5.9 dB each). CONCLUSIONS: Our results are in line with studies from European cities. Strikingly, all studies report noise reductions of about 5 dB. Aiming at a transformation to a health-promoting urban mobility can be a promising approach to mitigating health risks of noise in cities. Overall, the experiences currently generated by the pandemic offer data for best practices and policies for the development of healthy urban transportation-the effects of a lower traffic and more tranquil world were experienced firsthand by people during this time.

[Acoustic quality and urban health-more than just noise and silence]. / Akustische Qualität und Stadtgesundheit ­ Mehr als nur Lärm und Stille.

New approaches in urban development are required to transform cities into sustainable places. This demands a higher degree of urban density, which is hardly conceivable without an increase in sound - mostly in the form of noise. To achieve a high level of acceptance for densification, high-quality and acoustically pleasant urban spaces are essential. Noise reduction measures are necessary, but not sufficient. What is needed is a broadening of the perspective of noise. For urban public health we propose the soundscape approach from two different scientific disciplines. Here, sounds are qualities that can be designed in urban spaces and are an important resource for a healthy city. Linking knowledge about the acoustic environment with human perception will significantly improve our understanding of the relationships between urban acoustic environments, urban spatial contexts, and their effects on human health, both qualitatively and quantitatively. However, a systematic application of these approaches to urban soundscapes is still missing, as is the joint implementation of soundscape approaches in noise impact and urban public health research. This paper aims to introduce the terms sound and noise as well as two soundscape approaches. Subsequently, the aims and methods of the acoustic quality and health in urban environments (SALVE) pilot project are presented. The paper provides early insight into the new field of urban sound quality and soundscapes in the context of urban public health.