Noise Monitoring
Noise monitoring surveys were carried out at 10 external locations in each of nine different noise environments, giving 90 monitoring locations in total. The nine different noise environments were monitored at two locations in each of the five Merseyside local authority areas. The different noise environments were:
- Adjacent to a busy urban road.
- Adjacent to a motorway.
- Adjacent to a railway line.
- Adjacent to a transport interchange (either bus or railway station or major road junction).
- In a suburban residential street.
- In a city/town centre.
- Near the airport.
- In a city park.
- In a rural area.
Each of the noise surveys was carried out over a continuous 24 hour period on a weekday, with measurements not starting before 10:00am Monday morning and being completed before 4:00pm on Friday. Noise measurements were not carried out during school holidays. The survey methodology was chosen to provide data compatible with that used in the National Noise Incidence Survey.
The noise data were analysed to compare the results from Merseyside with the national results obtained in the NIS. The percentage of monitoring locations above the World Health Organisation guidelines for day-time and night-time noise levels likely to cause disturbance was identified. The range of noise levels measured in each of the nine different categories of noise environment and the range of noise levels in the 5 districts was also identified.
The spread of noise from linear transportation noise sources was modelled using the ‘Lima’ noise prediction software. The software was used to produce noise contours from a three dimensional model of the noise source and surrounding buildings and ground contours.
Predictions were carried out for five examples of motorways, main roads and railways, one in each of the five boroughs. The areas that were noise mapped were each approximately 1 km2, which included a residential area where there was one main linear noise source, either a motorway, ‘A’ road or railway.
In order to provide some validation of the measurements, 24 hour noise monitoring was also carried out at five locations adjacent to one example of motorways, main roads and railways.
The results of the noise monitoring and modelling are summarised in the full Merseyside Noise Study Final Report and are provided in full in the Technical Appendix to the Report.