Noise around the airport

Why and how is the noise around airports measured?
The noise from planes is measured for many reasons. It’s important to know whether the noise levels are going up over time, and if so, by how much.

In Britain, this noise is measured by averaging out the noise levels during the day (a 16-hour day) during the summer period. The amount of noise is given in decibels (dB).

This averaging-out means that the day’s high and low levels of noise are levelled out to give a single figure. The Government calls this averaged decibel measurement ‘LAeq’, and this is the most common international measure of aircraft noise. As a measurement, it means ‘equivalent continuous noise level’.

There are other units of measurement that can be used, and you can read about these and other technical noise information in BAA’s Issue Brief on noise, which can be found on this website www.baa.com/publications

What’s the average noise level near you?
In the UK, the Government says that people start being significantly annoyed by aircraft noise at 57 decibels, averaged over 16 hours (57dB LAeq). They use this as the starting point in policies on noise from planes
around airports.

To show where the different average noise levels are around the airport, the Government has developed maps with ‘noise contours’.

Below is the  ‘noise contour map’  for the area around Stansted. It works like a normal contour map that you would use for walking, or in geography.

 Click here to view an example.

The contours are an irregular shape because you get more noise at the ends of the runways (where planes take off and land) than at the sides.

This shows the contours for the averaged-out 57 decibels (57dB LAeq) for 2003, combining noise for all flights, regardless of the wind direction and therefore of the direction the planes were flying.

How many people are affected
In 1994, there were 692 people living in the 57 decibel noise contour around Stansted. By 2003, this had risen to 1,089 people.

This is because over the same time, the number of flights has more than tripled, from 57,700 in 1994 to 177,400 in 2004.