PORTLAND — City staff and councilors have not heard the last of a report on local noise levels, but preliminary results show Portland is not unique.
“The sound levels we measured during this study are typical of urban and suburban communities,” Ethan R. Brush of Acentech said in a Dec. 1, 2017, letter to Kevin Schneck, technical director of the city Department of Parks, Recreation, and Facilities.
The report was presented to the City Council Health & Human Services and Public Safety Committee Jan. 22. City Director of Public Assembly Facilities Andy Downs said there will be two more detailed presentations.
‘“I have to stress it is very preliminary. We don’t have all the information we want,” Downs said Monday of the report, adding it does create a baseline view of how noise affects daily life in Portland.
In August 2017, Acentech installed sound monitoring devices at 13 city sites and two more in South Portland. Sound levels were monitored from Aug. 7 through Nov. 12, 2017, in a study costing the city $50,000.
“The system hardware consists of a microphone with a windscreen, a data acquisition device, and a computer,” Brush said. “The microphones were calibrated in the field upon installation and their calibrations were all verified at the end of the study.”
Among the Portland sites selected were the Maine State Pier off Commercial Street, the Brick South building on Thompson’s Point, and intersections at Wharf and Dana streets, Stevens and Brighton avenues, and Congress and High streets.
While concerts at the Maine State Pier and Thompson’s Point generated the bulk of outdoor noise complaints noted in police activity logs from last July through September, street life itself tends to be noisier and more sustained, according to data.
Those findings are as critical, Downs said, and need more exploration as city government looks at quality of life and development issues.
“Our goal was to actually listen to the city as a whole and get a baseline of what the city sounds like,” he said.
At Congress and High streets, noise routinely exceeded 70 decibels except from midnight-4 a.m. Measured in minute-long bursts, it also frequently exceeded the 92-decibel limit placed on city entertainment venues.
That limit was exceeded 45 times at the intersection of Fore and Union streets during the study.
Downs also said data showing only one instance where 92 decibels was exceeded at a Maine State Pier show during the study does not concur with city measurements.
“The shows are at 92 decibels,” he said. “We take readings from multiple locations, but base it from the turnstiles.”
Acentech’s measurement of shows at the Maine State Pier was ultimately hampered when monitoring equipment was destroyed by water damage in a storm in early September. Data was not recorded after Sept. 6, 2017.
From July through September 2017, city police recorded 82 noise complaint calls about shows at the Maine State Pier. Downs said complaints are best made to police, who have direct contact with city staff working the concerts.
Downs said show operators Waterfront Concerts is responsive and sound levels are adjusted, but the type of sound and atmospheric conditions play roles in how sound travels.
“More detailed investigations are possible with the tremendous amount of data that has been gathered in this study,” Brush said, and Downs added the city and Acentech are now talking about what refinements and details should be part of the deeper study results.
“One that what will come out: should we be basing everything on decibel levels or are there other ways to look at it?” Downs said.