Excerpts from the Chicagotribune.com:

Some Streeterville residents, along with elected leaders, say they think the number of ambulances traveling through the downtown neighborhood is rising, as is the siren volume — and they want the fire department to do something about it.

A two-hour community meeting was hosted by the Streeterville Organization of Active Residents, a community group that has worked for five years to reduce noise it says is disrupting the peace of the lakefront community.

Downtown residents acknowledge that the wail of sirens isn’t new — especially in Streeterville, which is home not only to Northwestern Memorial Hospital but also Lurie Children’s Hospital. It’s likely the children’s hospital, which opened five years ago, increased the number of ambulances in the neighborhood.

One fire department official told the audience that the department’s ambulance sirens aren’t louder than they used to be and meet federal regulation. Still, the department is sensitive to concerns and has made at least 11 common-sense policy changes citywide over the years, such as reducing the frequency of activating sirens, aiming the sirens toward traffic in front of the emergency vehicle, and lowering the sirens from the roofs to the vehicle grilles, Fire Department spokesman Larry Langford told the audience.

Siren volumes on fire department ambulances and emergency vehicles are locked by the manufacturer — meaning that drivers can only turn them on and off — and meet federal regulations, Langford said. Lowering the volume, as some requested, is not a legal option, he told the group.

At 120 decibels, the sirens are just below the 123-decibel limit set by federal regulation. The sirens are at levels that get the attention of motorists, along with pedestrians on their phones or listening to music, Langford added.

The average citizen can handle short doses of a 120-decibel siren passing them, but prolonged exposure to it can lead to hearing loss, according to Dr. Dennis Moore, an assistant professor with Loyola Medicine’s otolaryngology department.

Moore did offer some advice to people on the street. “Typically it’s probably prudent if people are out and about if there’s sirens going by, I would literally stop what I’m doing and put my hands over my ears,” he said. “It’s like if something is too bright, you put sunglasses on. I always tell people we have eyelids, but we don’t have ear lids. They can’t close themselves up.”

Streeterville is a special challenge, Langford said during the meeting, because of the high density of people living, visiting and shopping in an area that’s home to two busy hospitals. While fire officials can make changes to lessen the impact on passers-by and pedestrians, they have less control over sounds that invade the area buildings, he said.

Some relief from the sirens could come next year when the University of Chicago Medicine’s trauma center opens on the South Side, diverting some of the patients who would go to Northwestern, according to Langford and Assistant Deputy Fire Commissioner Richard Edgeworth.

thanks Scott