Eagan has hired an out-of-state consultant to gauge the existing noise levels in the city before a new runway opens this fall at the Minneapolis-St. Paul International Airport.
City leaders want to be backed by independent data should they decide to sue or lodge any complaint over ramped-up airport noise.
The City Council voted unanimously Tuesday to start the noise monitoring in June.
"This is the only time that we can ever get this baseline data. The city recognizes that once this runway is operational there is no going back," said Dianne Miller, Eagan's staff liaison to the city's Airport Relations Commission.
The north-south runway, expected to open in late October, runs along Cedar Avenue, but flight paths are expected to fan across the southern metro. Areas of Eagan, Apple Valley, Burnsville and Bloomington should expect a noticeable increase in air traffic this fall, according to the Metropolitan Airports Commission.
The new runway, which will increase the airport's capacity by about 25 percent, adds five flight paths and about 290 new daily departures and arrivals above Eagan alone.
Eagan officials hope the data from the 10 new monitors will help them answer residents' questions about how they will be affected.
"There are several areas in Eagan that aren't impacted by any noise right now. Those residents are likely to be extremely noise sensitive," Council Member Peggy Carlson said. "Those areas will be the most hurt by the runway. We want to be able to respond accurately to their concerns."
The city also will use the baseline noise data to verify predictions of the MAC, which currently has eight permanent monitors in Eagan.
"We need independent data," said Carlson. "We need to double-check that what we are receiving is accurate and also to look at areas that aren't covered right now by (the MAC)."
Once the runway opens, the city intends to recheck the noise levels at the monitoring sites.
The Acoustics Group of Wyle Laboratories in Arlington, Va., will install the monitors in June for a seven-day measurement period. The company also will prepare independent projections on how many airplanes will be above Eagan and where.
"It hasn't been decided where the monitors will be located,'' said Wyle project director Bill Albee. "My guess is that they'd go up at schools, maybe churches see what levels are in some neighborhoods."
The MAC supports Eagan's move to bring in additional monitors, spokesman Patrick Hogan said.
"From our perspective, the more information we have on noise the better we are," he said. "We know that the noise impact will change once the new runway opens."