Keeping the Peace
Permanent, 24 hour a day, 365 days a year, noise monitoring controls adherence to noise limits and allows a wide range of additional benefits. Permanent noise monitoring is used by an ever-growing variety of organisations.
For many major airports, permanent noise level monitoring is a key issue in the daily running of the airport as noise is often the number one complaint from neighbouring residents. Airport authorities have established regulations with the aim of reducing the impact caused by their operations as much as possible. They hope that these regulations will not only give them the ability to ensure that aeroplanes and pilots adhere to their regulations, but also prevent complaints.
It is often necessary to have both noise data and information about the trajectories followed by approaching or departing aeroplanes. Normally, the airport's own radar provides the required information and, once correlated with noise data, it can easily be used to determine excess noise levels for specific aeroplanes.
Permanent monitoring of noise in cities covers:
- Construction sites
- Major roads
- Major railways
- Concert, exhibition and sports arenas
It is usually used when strict noise limits are imposed by the authorities or to protect against law actions, complaints and compensation claims. Permanent monitoring can indicate noise trends and help produce noise maps.
In addition, semi-permanent noise monitoring, typically ranging from a few days up to several weeks, is also used for cost-effective monitoring of noise trends, limit compliance, public awareness, improved knowledge of dose-response relationships and calibration of noise maps.
Often, a Global Positioning System (GPS) device is used to automatically locate the measurement position. Thus, geographically referenced, measured data from mobile NMTs can be used for locally calibrating calculated maps. Local calibration involves collecting representative values for a particular period in a particular geographic area and transferring to a calculation software. Here, emission levels of user-defined sources are adjusted so that the resulting map matches the actual situation.