(Virtual showroom): Environmental noise is subjective as it is based on people’s perceptions of specific sounds. Environmental noise is defined as any unwanted sound created by human interaction with the natural environment. Environmental noise typically refers to noise associated with an outdoor sound produced by industry, various forms of transport and recreational activities. Environmental noise can therefore be considered as a form of pollution. By definition, pollution is something that is to be avoided, controlled, regulated, or eliminated due to its negative impact on humans and human-environment relationships (Murphy and King, 2014). Noise impacts may comprise of physiological (influence on communication and, productivity and even impaired hearing) and psychological effects (stress, frustration and disturbed sleep).
The capacity of noise to induce annoyance depends upon its physical characteristics, including the sound pressure level, spectral characteristics and variations of these properties with time. During the daytime, few people are highly annoyed at LAeq levels below 55 dBA, and few are moderately annoyed at LAeq levels below 50 dBA. Sound levels during the evening and night should be 5–10 dB lower than during the day.
As previously mentioned, environmental noise can result in or be a trigger for more serious health problems. Therefore, it is important to determine the impact on the environment. Noise assessments can be conducted to determine the current conditions or character of noise in a specific area to identify possible impacts and to provide mitigation measures should it be found that an impact does occur. It is crucial to understand the current noise environment of an area to be able to define the impact of the activity on both sound generated during the day and the night.
The South African National Standard (SANS) 10103, the latest edition of which is SANS 10103:2008 - The Measurement and Rating of Environmental Noise with Respect to Annoyance and to Speech Communication, provides guidance in defining noise impact criteria limits and standards and is also used by local authorities in the control of environmental noise. A study must be conducted in terms of the provisions of SANS 10103 of 2008, during a day and night time period, for a minimum of ten (10) minutes per identified locality. A certified and calibrated sound level meter is required to provide accurate and reliable measurements. The noise assessment is compiled by studying and analysing the activities and by determining the possible noise impacts these activities will have on the surrounding land users.
The assessments comprise of the following important aspects:
- Determination of the ambient noise conditions through a physical noise assessment.
- Determination of the possibility of noise that may affect sensitive receptors in the area.
- Determination of the current noise-generating activities and noise levels in the area.
- Determination of the possible noise impact; and
- Provide recommendations and mitigation measures.