It’s no secret to nearby residents and businesses that Centennial Airport is a busy place.

Despite ranking as the 23rd busiest airport in the country in 2015 by number of operations — hosting an estimated 317,000 takeoffs and landings — recent noise mapping efforts undertaken by the Arapahoe County Public Airport Authority show that its major noise influence area, as defined by the Federal Aviation Administration, has shrunk in recent years.

The airport, with the help of consultants, has produced a draft noise exposure map that it will submit to the FAA by the end of the year, staff members say. The hope is that the FAA will approve the map in the first quarter of 2017. The downloadable map — found at the airport’s website — is meant to serve as a reference over the next five years, so potential homeowners, developers and community planners can use it to better determine where they can expect significant airport noise.

“What’s important to recognize about the map is it represents a very static picture of our noise footprint,” said Aaron Repp, a noise and environmental specialist at the airport. “But we’ve seen an overall decrease in the size of our noise contours.”

This is the second time Centennial Airport has compiled a map. The first was in 2008.

The map establishes noise contours surrounding the airport using data collected between Oct. 1, 2014, and Sept. 30, 2015. The outer most contour represents where noise can be expected to reach 65 decibels, the noise level the FAA defines as significantly impactful, according to Centennial Airport materials.

For reference, a normal conversation is generally about 65 decibels, while a chainsaw or rock concert can reach 110 decibels.

Repp said the process for creating the noise contours is complex, involving calculating a 24-hour logarithmic average of noise with a 10 decibel penalty at night — and the contours themselves are fluid, with busier days likely to expand the borders. Interviews with airport tenants about their operations and planned future growth also factored into the map.

Given the data at hand, the 65-decibel contour shrank by 970 acres compared to the 2008 map, Repp said. Previously enveloping 1,300 homes, the noise area now includes none.

“I think this is going to be a valuable tool for the airport and the local jurisdictions in continuing to plan the ever-expanding growth of this area,” Repp said.

Many factors may have helped shrink the contours. Repp noted an FAA ban of louder “Phase II” jet aircrafts took effect last year. Dylan Heberlein, a fellow noise and environmental specialist, said pilots now often use global positioning systems to zero in on landings, potentially narrowing noise corridors.

The airport has launched numerous efforts to better track and curb noise since 2008. It distributes voluntary noise abatement guidelines to operators and pilots. It established a 12-site, $1.4 million noise monitoring system to allow for accurate tracking of noise events by the airport and the public. Repp said the airport is currently trying out — and seeking FAA approval for — a new nighttime takeoff pattern for flights going north that sends planes over Cherry Creek State Park instead of over homes near Arapahoe Road.

Ryan Sarni is president of the Cherry Creek Vista South Homeowners Association and has lived about two miles from the airport for three years. He sees ways the airport could improve its noise abatement efforts — perhaps by working with flight schools to keep takeoff and landing procedures closer to the airport — but he has been encouraged by the progress.

“That nighttime takeoff procedure has been a huge improvement,” Sarni said. “When we first moved here, they would wake my kid up once in a while. That doesn’t happen anymore. We think that’s a great example of collaboration.”

In its capacity as a referral agency, the airport has used its noise data to make recommendations regarding projects. A residential development was recently rejected by the Centennial City Council. Mayor Cathy Noon said she voted against it in part because residents would likely have dealt with significant airport noise.

Councilwoman and Air Force veteran Candace Moon was out of town for that vote, but represents Centennial on the airport’s Community Noise Roundtable. She thinks the noise map will be an asset should the FAA approve it.

“The tool itself is very useful,” she said. “I think that the airport authority has really gone out of their way to try to address people’s concerns about noise.”