Noise Monitoring 

Scattered across the Boston Metropolitan area are 30 listening stations that gather the data that Massport uses to minimize the noise that Logan Airport brings to the community. Each day, 365 days of the year, readings are taken from sensitive noise monitors that are able to sort out the sound of a passing plane thousands of feet overhead from the routine din of neighborhood traffic a few feet down below.

The results of these readings help Massport monitor flight tracks, respond to community complaints, better understand how Logan impacts communities day to day and to participate more effectively every year in the revision of Logan's noise contours, by verifying the accuracy of the FAA's computer generated Integrated Noise Model(INM). The INM is used to determine eligibility for government-supported soundproofing.

The FAA uses an Integrated Noise Model to compute sound level noise contours around the airport. The contours are annual measures for day and night and define the sound impacts of Logan Airport on particular communities. They are used for planning and mitigation purposes, and to determine eligibility for soundproofing. On-going monitoring conducted by Massport is used to check the accuracy of these computer generated models. Over the years, Massport has worked proactively with the FAA to make the INM better "fit" Logan. For example, the INM has been adjusted, with FAA approval, to reflect topography unique to Logan: terrain and water. These adjustments have allowed Massport to expand the eligibility for soundproofing. The terrain adjustment alone has made more than 500 additional dwelling units eligible for federal soundproofing.

65 DNL is a level the FAA says is incompatible with residential communities. Population exposed to levels of noise in excess of 65 dB DNL decreased from 9,438 in 2004 to 6,477 in 2005, approximately 31%.

Winthrop, which has always experienced the highest levels of exposure of any community around Logan Airport, continued its decline in number of people exposed to levels greater then 65 dB DNL in 2005. This number has dropped 81% since reaching its peak in 1998.

Over the years, Massport has made major gains in minimizing noise. Tough nighttime restrictions on operations, community noise goals that distribute traffic, and other local mitigation measures, have dramatically decreased the exposure in the communities that surround Logan Airport.

By 2005, the population exposed to significant levels of noise was the lowest since 1987, when population counts were first assessed and reported. The latest count showed that the total number of people exposed to more than 65 decibels decreased from nearly 67,000 in 1987 to less than 6,500 in 2005.