Understanding environmental noise: Transmission, attenuation, resonance and health implications

Abstract

This paper investigates the behavior of environmental noise, a critical topic for acoustic experts. Sound and noise propagate through various media via pressure variations, with attenuation significantly influenced by environmental factors, source types, frequencies, and climatic conditions. Attenuation refers to the reduction of sound intensity. Noise sources are classified into point, line, and plane categories. Sound is perceived by the human ear, while noise is unwanted sound. The distinction between the two depends on individual perception, the environment, and circumstances. Noise can be audible or inaudible, with inaudible noise, such as infrasound and ultrasound, potentially posing health risks. This paper examines noise attenuation in relation to sources, frequencies, and site conditions such as resonance phenomena. It also addresses the limitations of current acoustic measurement technologies and proposes advancements for the field of acoustic science due to neglecting resonance phenomena. By understanding these factors, we can effectively assess and mitigate the impact of noise on human and animal health and the environment.

What is known: Sound and noise propagate through pressure variations in air, liquid, or solid. Noise sources are categorized into point, line, and plane sources. While sound is what we hear, noise is considered unwanted sound. The reduction of sound intensity, known as attenuation, varies based on environmental factors, source types, and frequencies. Attenuation is frequency-dependent, with higher frequencies generally experiencing greater attenuation. The surrounding environment, whether it consists of hard or soft sites, significantly impacts attenuation. Current acoustic measurement technologies, such as FFT analysis, have limitations in terms of frequency resolution and transducer capabilities.

What this paper adds: This paper adds to the existing knowledge by providing a comprehensive analysis of noise attenuation, covering point, line, and plane sources, frequency-dependent attenuation, and environmental factors. It specifically addresses the often-overlooked attenuation of infrasound and explores the unique characteristics of both natural resonance noises. The paper discusses the limitations of FFT frequency resolution and its impact on acoustic signal measurement, suggesting potential advancements in acoustic measurement technologies to address these limitations. Additionally, it highlights the potential health implications of infrasound, including its ability to cause resonance and amplify sound levels. By offering a detailed overview and addressing specific gaps in knowledge, this paper contributes to a better understanding of environmental noise and its implications for human health and the environment.