A data dive into aircraft noise

Credit: Kevin Terrell presents his airport noise analysis in early August at Edina City Hall. Photo by Michelle Bruch

A Lynnhurst resident thinks the Federal Aviation Administration is ignoring the true impact of airplane noise in the noise maps it typically publishes. So he made some of his own.

Kevin Terrell and a handful of neighborhood groups spent $1,800 on a Freedom of Information Act request to get raw data on plane noise from 89 national airports. Then he partnered with the University of Minnesota’s Center for Urban and Regional Affairs to crunch the numbers and match noise level data to census data. Now he’s published an interactive map that shows the average noise level of planes in decibels, down to the block level.*

“This is the only place that 55 db contour maps exist in the country,” said Terrell, cofounder of the local airport noise advocacy group MSP FairSkies Coalition.

The FAA uses a 24-hour average sound level called the DNL (day-night average sound level) which includes a penalty for nighttime noise. The FAA considers a “significant” noise impact to be a 1.5 db change at or above 65 DNL. In Minneapolis, homes that persistently sit inside the 60 DNL line can receive noise mitigation.

Terrell thinks the FAA’s current noise threshold doesn’t go far enough, because the 65 db level is based on 40-year-old research. Updated research says aircraft noise is perceived as more annoying than earlier studies, he said, and it’s deemed more annoying than other types of transportation.

“As societies become wealthier, they are much more willing to pay for peace and quiet,” he said.

Using the 55 db metric, Terrell says plane noise is far more impactful than people realize, reaching more than 70,000 in Minneapolis, 386,000 in LA and 688,000 in New York.** In Southwest Minneapolis, the 55 db map stretches to the western border of the city and covers areas including Lake Nokomis and Lake Hiawatha, Diamond Lake and Lake Harriet.

At a presentation of Terrell’s noise analysis in early August, Metropolitan Airports Commissioner Lisa Peilen said the airport follows FAA guidelines related to noise.

“Noise is a big issue, I understand that,” she said.

Dana Nelson, the Metropolitan Airports Commission’s manager of Noise, Environment and Planning, noted that the airport’s Noise Oversight Committee has asked the FAA to provide a community engagement plan for any future consolidation of flight tracks out of the airport. The NOC has also requested a case study showing successful implementation of such a program over a similar densely-populated city.

At the August meeting, Nelson noticed that the FOIA data sources appeared to be outdated.

Terrell said his data is from 2010, at a time when the FAA was relying on outdated MSP flight tracks. He’s since learned the FAA has more recent data available, and he’s submitting a new FOIA request for an update.

National advocacy

MSP FairSkies’ advocacy comes at a time when some members of Congress are pushing for a 55 DNL noise metric. Congressmen formed a new Quiet Skies Caucus last year, and sent a letter to the FAA last month:

“…[The] FAA should lower the current threshold from 65 to 55 DNL to reflect the fact that this standard, first established in the 1970’s, is arbitrary and does not align with current health research and the lived experience of families in our congressional districts,” states the letter.

The Caucus also wants to stop an automatic exclusion from environmental review that currently applies to a nationwide implementation of new flight tracks.

Congressman Keith Ellison is a member of the Quiet Skies Caucus, and Terrell said he’s hoping to see Congressman Erik Paulsen join as well. He would be the first Republican to join the Caucus.

The FAA is currently in the process of reevaluating its method for measuring the effects of aircraft noise. As part of a multiyear effort to update the scientific evidence on the impact of plane noise, the FAA is privately polling residents around 20 airports.

The FAA said in a press release last spring that it established the 65 DNL threshold in 1981, based on transportation noise surveys in the 70s.

“During the ensuing years, aircraft manufacturers incorporated technologies that resulted in dramatically quieter aircraft. However, residents around many of the largest U.S. airports have expressed concerns about aircraft noise associated with the continuing growth of the aviation industry,” said the release. “If changes are warranted, the FAA will propose revised policy and related guidance and regulations…”

In discussions about plane noise, airport officials often note a long-running improvement in quieter aircraft technology. A three-year-old report from the U.S. Government Accountability Office says the number of people exposed to significant aircraft noise (65+ DNL) has declined from about 7 million people in 1975 to about 309,000 people in 2012. The change reflects improvements in aircraft technology, according to the GAO, and large reductions in areas exposed to plane noise.

A class project

Terrell expects to publicize his findings nationally. A new interactive graphic maps plane noise down to the block level at the 35 largest U.S. airports. (Note: Map works best in Google Chrome browser.)

“Part of the point of this is I wanted to see what it looked like across the country,” Terrell said.

Terrell created the maps in partnership with CURA at the U of M, and the mapping became a class project. Each student in the 2015 spring semester Urban GIS and Analysis class was assigned a different airport to map. The class also linked the noise data to poverty data to see if there was any relationship. (They didn’t find much of a relationship to poverty in Minneapolis, though it’s a bit stronger in places like Chicago.)

CURA provides data and mapping assistance to about 100 nonprofits and neighborhood groups each year.

“We were also kind of interested in the government transparency angle,” said Jeff Matson, CURA’s Community GIS program director. “The FAA is collecting all this data and not readily sharing it.”

As part of the analysis, Terrell compared Minneapolis’ noise impact with international cities.

“Minneapolis-St. Paul, which is about the 15th busiest airport in the U.S., has more than twice the number of people impacted by noise as Amsterdam,” he said.

To address plane noise, the Amsterdam airport has increased landing fees for noisier aircraft and reduced fees for quieter planes. (There are legal questions around whether airports can issue variable noise-based landing fees.) Amsterdam also addresses the issue by sending planes over tulip fields and landscaping designed to deaden plane noise, Terrell said.

“It’s not surprising that because they are taking action as a community to lessen noise, they get less of it,” he said.

Terrell also highlights research linked to the health impacts of plane noise, and the impact on kids in school. He said he’s not pushing for more noise mitigation in individual homes in Minneapolis. Instead he wants a transparent discussion about plane noise.

“I want a discussion around the facts, where significant impact really happens, and make decisions based on that,” he said.

To see the analysis, visit mspfairskies.com.


 *Map works best in Google Chrome browser

**The number of people impacted in New York and LA has been changed to reflect the 55 db, rather than 54 db, noise contour.