Noise level refers to the intensity of sound in a given environment and is typically measured in decibels (dB). While sound is a natural and essential part of everyday life—supporting communication, awareness, and interaction—excessive or unwanted sound is considered noise and can negatively impact both human health and environmental quality.
In outdoor environments, noise is mainly generated by human activities such as traffic, construction, industrial operations, air traffic, and urban nightlife. Monitoring noise levels is especially important in cities, where high population density and infrastructure can lead to persistent noise pollution.
Noise plays a significant role in overall environmental quality. Although it is not an air pollutant in the traditional sense, it is closely linked to urbanization and often correlates with other pollution sources. Monitoring noise alongside air quality parameters provides a more comprehensive understanding of environmental conditions.
Exposure to elevated noise levels can have a range of negative effects on human health. Prolonged exposure may lead to hearing damage or loss, particularly at higher sound levels. Noise pollution is also associated with sleep disturbances, increased stress, and reduced concentration. In the long term, it has been linked to cardiovascular issues such as high blood pressure and heart disease, as well as mental health effects including anxiety and fatigue.
Even at moderate levels, continuous noise can impair cognitive performance and productivity, especially in environments such as schools and workplaces.
Although acceptable noise levels vary depending on the environment and context, general reference points include:
• Below 40 dB: quiet environment (e.g. libraries, bedrooms)
• 40–70 dB: typical daily environments (e.g. offices, conversation)
• Above 80 dB: prolonged exposure may pose health risks
• Above 130 dB: immediate risk of hearing damage
Noise levels cannot always be controlled, especially outdoors, but they can be managed and monitored. Using noise sensors allows for continuous tracking of sound levels, helping to identify sources of noise pollution and support data-driven decisions to improve environmental quality.
In indoor environments, noise can be reduced through soundproofing, better space design, and managing noise sources. Outdoors, monitoring helps cities and communities implement targeted measures to reduce noise exposure and improve overall quality of life.