Two years ago, city officials thought they had found an answer. They distributed 100,000 trash cans to residents and made them pledge to toss their refuse in the plastic cans, not the streets.
But the problem of inadequate trash-can use persists. Officials say residents are using the receptacles at dismal rates, as low as 20 percent in some neighborhoods. As a result, the city has an estimated 3.25 million rats.
"We need to do something," said Elizabeth Weiblen, deputy director of the Mayor's Office of Neighborhoods. "We can't give up."
And so Baltimore is embarking on an ambitious effort to persuade residents to dump trash in covered cans - an effort drawing on behavioral analysis, market research and product placement.
Officials don't know where the focus groups and interviews that began yesterday will lead them, but they say review of the results, identification of key factors and development of a response might prompt changes beyond trash pickup.
"This is about behavioral change in trash-can use," said Mary M. Hennigan, a technical adviser at Catholic Relief Services, who is helping the city apply a technique used to persuade residents of Third World countries to use latrines.
That technique, Hennigan said, is called "barrier analysis." It involves questioning trash-can users and nonusers alike to determine the sources of their behavior, then formulating an intervention plan to modify the behavior, and finally implementing that plan.
Residents and community leaders say something needs to be done, and soon. "At this point, I have never seen Baltimore this dirty, and I am a Baltimorean for many years," said Pearl Moulton, a retired professor of social work from Mondawmin.
Moulton said she regularly sees paper and other trash blowing through her neighborhood. As she told an interviewer from the city yesterday, neighbors put out their trash in paper bags, which dogs ravage before they can be picked up.
"In your experience, what are the pros and cons of using a trash can?" Moulton's interviewer asked her, going through a checklist of 14 questions intended to reveal perceptions and behaviors that contribute to trash-can use.
"It's just good sanitary practice," Moulton answered.
Hector G. Manzano of the city's Public Works Department said not using covered cans gives rise to rats. The rodents easily gnaw through bags to feed on the refuse.
City code punishes can disuse, Manzano said. Yet despite the threat of fines reaching $450, many ignore the rule. Residents complain about neighbors tossing plastic trash bags onto the sidewalk or into vacant houses.
"Ugh, it's sad," said Sarah Murray, who lives in the Abell neighborhood, not far from the public library in Waverly where she was among four residents interviewed as part of the project.
Ten years living in a rowhouse on 33rd Street has given Murray two main explanations for the phenomenon: Renters don't use the cans, and collectors don't take all of the trash from the alley behind her house.
The city's interview with Murray suggested a possible course of action in the campaign to encourage trash-can use: Focus on disgust with rats.
"Rats in Baltimore have been known to carry as many as 15 diseases," the interviewer said.
"Don't tell me," Murray interrupted. "I'm a very imaginative person."
City officials did not give a timeline for completing the questioning and creating a response.
"This is about helping people to tackle an issue they may feel is out of control in Baltimore," said Virginia Geckler of the Mayor's Office of Neighborhoods.