støj

Støj is the Danish term for unwanted sound or auditory disturbance. In everyday use it covers environmental noise such as traffic, industry, neighbour noise, and equipment noise, as well as electronic or signal-processing noise that degrades a desired signal. In acoustics, noise is often described as a broad-spectrum, aperiodic sound, in contrast to tonal or speech signals.

Common sources include road traffic, railways, aviation, construction, factories, and loud recreational activities. Noise can be steady or intermittent, impulsive or continuous, and may vary by frequency content and time of day. Environmental noise is a major consideration in urban planning and public health, while industrial noise is a key concern in workplaces and communities.

Measurement and assessment of noise rely on sound pressure levels reported in decibels (dB). For human perception, levels are typically weighted with A-weighting, resulting in dBA values. Measurements use a reference sound pressure of 20 micropascals and follow international standards and guidelines to characterize exposure, annoyance, and potential health impacts.

Health and social effects of substantial noise exposure include temporary or permanent hearing loss, tinnitus, sleep disturbance, cardiovascular stress, and reduced cognitive performance. Vulnerable populations, such as children and the elderly, may be especially affected, and cumulative exposure from multiple sources is commonly considered in assessments.

Mitigation approaches combine planning and technology: land-use zoning, noise barriers, improved building insulation, quiet pavements, traffic management, and operational controls in industry. Public policies often set exposure limits, with ongoing efforts to reduce nuisance and protect health while maintaining essential transportation and economic activities.