Aerodynamic Wind Turbine Emissions and Vestibulo-Cochlear Coupling: Impulsive Pressure Signatures and Their Health Relevance

Abstract

Background: Wind turbine–related airborne emissions are commonly assessed within a classical acoustic framework, extending conventional sound concepts into the infrasonic range. However, increasing empirical observations and physiological reports suggest that this approach insufficiently captures the physical nature and biological relevance of wind turbine exposure.

Objectives: This study aims to provide a physically consistent classification of wind turbine emissions based on their aerodynamic origin and to link these emission forms to plausible physiological interaction pathways. A central objective is to distinguish harmonic acoustic phenomena from non-harmonic, impulse-dominated pressure dynamics and to introduce the concept of wind turbine emission signatures as an integrative descriptor.

Methods and conceptual framework: Wind turbine emissions are analyzed along an aerodynamic–energetic cascade, differentiating four airborne emission forms ranging from flow-bound volume-flow modulation to impulsive, acoustically describable infrasonic pressure signals. The analysis emphasizes time-domain characteristics, energy transfer mechanisms, and the distinction between periodicity and harmonicity. Physiological interaction is examined with particular focus on vestibulo-cochlear coupling and autonomic regulation.

Results: Wind turbine rotor systems generate sequences of discrete aerodynamic events rather than continuous oscillatory sound sources. Periodic repetition of these events produces spectral components that reflect mathematical periodicity, not harmonic sound generation. A substantial fraction of signals commonly measured and reported as wind turbine infrasound consists of impulsive, temporally asymmetric pressure events that retain their non-harmonic character over large distances. These structured pressure impulses form a characteristic wind turbine emission signature. From a physiological perspective, such signals preferentially interact with the vestibulo-cochlear system, which is highly sensitive to low-frequency pressure gradients and fluid displacement, even below auditory perception thresholds.

Conclusions: Framing wind turbine emissions in aerodynamic and vestibular rather than purely acoustic terms resolves several inconsistencies in the existing literature. The concept of wind turbine emission signatures provides a coherent link between emission physics, measurement characteristics, and reported health effects. This framework supports a shift from level-based acoustic metrics toward time- and structure-sensitive assessment approaches in environmental and medical evaluations of wind turbine exposure.