The poor are more likely to smoke than those above the poverty line.
In Philadelphia, there's a 50 percent higher prevalence of smoking among the poor than among the non-poor, according to Giridhar Mallya, director of policy and planning for the Philadelphia Department of Public Health.
The poorest of the 10 largest U.S. cities, Philadelphia also has one of the highest rates of smoking of any big city, according to a health department report.
Lower-income neighborhoods such as Kensington, Bridesburg, and Port Richmond are among the city's most smoker-prevalent neighborhoods, department research shows.
The poor smoke to manage high levels of stress and depression, Mallya said, as much a part of poverty as empty pockets.
Then, too, the poor are more likely to be exposed to nearly ubiquitous cigarette advertising at corner stores, which exacerbates smoking, Mallya said.
It's also harder for the poor to get smoking-cessation counseling and nicotine patches than others who may receive help through insurance, experts said.
Even as health insurance comes to the poor through the Affordable Care Act, smoking remains a problem: Smokers may be charged a premium of up to 50 percent, according to Frank Leone, director of the Comprehensive Smoking Treatment Program at the University of Pennsylvania.
'Keep you sane'
Mariana Chilton, a professor at Drexel University's School of Public Health, noted the complex link between smoking and poverty:
"When you're deprived, it creates enormous mental anguish," said Chilton, an expert on hunger. "One of the fastest, most convenient ways to help is a cigarette. It'll keep you sane, and keep you from hurting yourself or others."
Smoking is also a way to deal with hunger, Chilton said. Families without enough to eat are more likely to smoke than food-secure families, she said.
"Smoking treats hunger pangs," Chilton said. "Instead of having lunch, mothers will feed their children, then smoke."
That's how it works in Camden, said Elaine Styles, 51, a laid-off day-care worker.
"I smoke so I don't have to eat," she said. "I make sure my family eats, then I have a loosie [a cigarette sold singly for 50 cents or so] and go to bed."
Because smoking is costly, people ask, aren't the poor being irresponsible for mis-allocating money better spent on food?
Low-income smokers nationally spend 14 percent of household income on cigarettes, Mallya said. In Philadelphia, the average smoker spends about $1,000 a year on cigarettes, he added.
Mallya laments the fact that cigarettes in Philadelphia are relatively cheap - $5 to $6 a pack - compared with other cities where added taxes make them more dear. The more cigarettes cost, the fewer are smoked, he said.
The morality of buying cigarettes when you're poor is complicated. Most poor people want to quit smoking, surveys show. But poverty itself, combined with the overwhelming power of nicotine, make stopping hard.
"People smoke knowing is not good for them," said Leone of Penn, who is also a pulmonologist. "Nicotine gets into the part of the brain stem that creates a sense of safety, comfort, warmth. If you have to decide between buying bread or cigarettes, not buying cigarettes creates a disease and agitation in the brain that says there's only one way to fix this situation: Just smoke."
Yale University sociologist Elijah Anderson said people shouldn't "blame the victim" by denigrating smoking behavior without understanding poverty, its underlying causes, and a poor person's "limited sense of having a future."
Among the poor, especially low-income African Americans, menthol worsens smoking.
A flavor added to cigarettes, menthol makes the cigarette taste less harsh, which causes the smoker to take deeper, more frequent drags, Mallya said.
That, in turn, increases the harm of cigarettes.
For 50 years, menthol cigarettes were promoted in black neighborhoods; now, 90 percent of African American smokers in Philadelphia smoke menthol cigarettes, Mallya said.
"There may be something biological at work," Leone said, adding that science is studying whether race makes a difference. "But that doesn't cloud the intense effort by cigarette marketers."
In a city where black people already suffer greatly from asthma - Philadelphia is among the top-five worst asthma cities in America, experts say - smoking aggravates everything, especially among children, said Brad Collins, professor of public health and pediatrics at Temple University.
Jerry Goldstein, a pediatrician at St. Christopher's Hospital for Children, agreed. "Second- and third-hand smoke [found on clothing and walls] are seriously exacerbating kids' asthma," he said.
This is not to say all is hopeless. While still high, rates of secondhand smoke exposure in the city have decreased by nearly 7 percentage points between 2004 and 2012, health department research shows. And teen smoking is down from nearly 16 percent to over 9 percent in the same time frame, while there are slightly fewer adults lighting up these days.
Mallya attributes that to an intensive public education program and his department's efforts to help get many poor people smoking-cessation help.
But that doesn't mean the air will clean up any time soon.
As Amy Hillier, a professor in Penn's School of Design, who helped study cigarette advertising, said, "Sometimes a pack of Marlboros will save someone's life in terms of stress."