Editor’s Note: In this three-part series focusing on the pope and urban environments, National Geographic profiles the struggles of a neighborhood in each city Pope Francis is visiting: Washington, D.C., Philadelphia, and New York City.

Inside her dank and cramped apartment in a public housing project, Tai-Sheba Smith sometimes watches her 11-year-old son sleep at night. She worries that he’ll have an asthma attack in his sleep and stop breathing.

Smith’s fears are more than just maternal angst: Manhattan’s gritty traffic exhaust can contribute to deadly asthma attacks and an array of other children’s health problems. In her neighborhood of East Harlem, kids are sent to emergency rooms for asthma nearly three times as often as kids in the rest of the city.

“The air isn’t good here,” she says, “inside or outside.”

Smith, a single mother and part-time cosmetologist and student, struggles to support her three young kids—two of whom suffer from asthma—in Manhattan’s poorest neighborhood. Every year in New York City alone, nearly 40,000 children suffer asthma attacks so serious they are treated in emergency rooms.

On Friday, Pope Francis, the global leader of the Roman Catholic Church, will visit her neighborhood to meet with families striving to subsist in one of the world’s wealthiest cities. Residents like Smith hope the pope’s visit will bring attention to their struggles. (Read “Blocks From the Pope’s Mass, a Dumping Ground for the Nation’s Capital.”)

The pontiff has called environmental justice for the poor an ethical imperative. “The gravest effects of all attacks on the environment are suffered by the poorest,” he wrote in an encyclical he unveiled in June. Air pollution, he wrote, “produces a broad spectrum of health hazards, especially for the poor, and causes millions of premature deaths.”

View Images Tai-Sheba Smith points to a vent in the bathroom of the East Harlem public housing apartment she shares with her three children, including her 11-year-old asthmatic son. After men in hazmat suits came to clear out the vents, black soot covered the bathroom.

The pope’s entreaties about poverty and the environment are especially relevant in East Harlem, where families are disproportionately harmed by air pollution because mold, cockroaches, and other poor housing conditions exacerbate the health hazards inside their homes.

“We tend to pay more attention to environmental issues we can see, like the exhaust coming out of buses and trucks, than the social inequities that are perpetuating a problem,” says Ogonnaya Dotson-Newman, director of environmental health for the advocacy group West Harlem Environmental Action.

Soot and Exhaust in East Harlem

East Harlem, sometimes called Spanish Harlem or El Barrio, has long been the heart of Hispanic culture in New York. Directly north of the affluent Upper East Side and to the north and east of Central Park, the community is home to a large population of Puerto Ricans and Dominican and Mexican immigrants. About half the 110,000 people living in the 1.5-square-mile area consider themselves Hispanic or Latino, and roughly a third are black. The neighborhood has two bus depots, a garbage truck depot, and 24 public housing projects.

View Images Pope Francis will visit Our Lady Queen of Angels School on Friday to meet with East Harlem families.

The city’s air pollution is caused by a mix of car and truck exhaust, heating fuel, and upwind soot from the Midwest’s coal-fired power plants. Lung-damaging particles of soot can move from outdoors to indoors, making them hard to escape.

The city’s air is cleaner than it was a couple of decades ago, due to anti-idling laws and cleaner fuels and vehicles. Yet New York’s air remains among the nation’s most polluted, with one estimate tying the pollution to an estimated 2,000 deaths in the city each year. In the past decade, New York moved from seventh place to fourth among the nation’s nine largest cities for particulate pollution.

The fumes—linked to asthma attacks but also to cancer, reduced IQs, child behavioral problems, and heart attacks—waft across the city. “Air pollution doesn’t obey boundaries,” says Frederica Perera, director of Columbia University’s Center for Children’s Environmental Health.

In East Harlem every year, 73 of every 1,000 kids under the age of 15 are treated by emergency room doctors for asthma attacks, compared with 27 of every 1,000 citywide. And they wind up hospitalized for asthma at more than twice the city rate.

Yet outdoor air pollution can’t totally explain why more kids in East Harlem are sick with asthma. The wealthy Upper East Side has recorded some of the city’s highest levels of air pollution, but kids there are nine times less likely to be hospitalized for an asthma attack than children growing up just blocks away in East Harlem.

View Images Elizabeth Gonzalez, who lives in public housing less than a block from the church school where the pope will meet East Harlem residents, keeps a list of maintenance problems at her apartment. City officials are slow to respond. Everyone in her family has asthma. “I’m happy to have a roof over my head, but this apartment is keeping us sick,” says Gonzalez, a grade school assistant teacher.

So why are low-income kids more susceptible? Part of the reason may be poor preventive health care; they don’t get the medications they need to prevent asthma attacks. Blacks nationwide have much higher overall rates of asthma. But the stress of poverty could be a big factor too. The crushing insecurity that comes from struggling to pay rent or feed a family may help explain some of the health disparities between New York’s poorest and richest residents, Perera says.

Earlier this year Perera’s research team found that being poor increases the effects of air pollution on children’s developing brains. Mothers in northern Manhattan and the Bronx who had been exposed to toxic pollutants in car exhaust and also struggled through pregnancy to pay for food, clothing, and shelter had children with lower IQs at age seven than kids whose moms didn’t face financial hardship. All the mothers studied were African-American or immigrants from the Dominican Republic.

Those findings, Perera says, add to a growing body of research showing that the chronic stressors of poverty may fundamentally alter the way the body reacts to everyday pollutants.

“Among socioeconomic factors, adequate housing is a critical factor in emotional well-being,” she says.

In East Harlem the poor are relegated to apartments with leaky pipes, moldy walls, and roach infestations. Roughly 44 percent of households live on less than $25,000 each year. They often lack the financial and social capital to force improvements in housing or to move out.

View Images Hermelinda Basurto talks with a community health worker about the roaches and bedbugs in the apartment where she and José Espinoza are raising their five children. If she could speak with the pope, she says, she would tell him about the unhealthful living conditions in East Harlem.

Jim McCormick, a housing attorney for Legal Services New York City, a nonprofit law office, perceives a great deal of stress, anxiety, and depression among his low-income clients.

“Housing in New York City is stressful for everyone, but the poor put up with so much more,” he says. “As a society, we have this sense that the poor deserve substandard housing, that their situation is due to bad choices or some lack of ambition. We let those misguided thoughts drive our policies.”

The pope, in his writings, also describes the connection between good health and good housing.

“Having a home has much to do with a sense of personal dignity,” wrote the pope, who calls lack of adequate housing a “grave problem” in much of the world. Unsanitary and dangerous living conditions, he says, can “heap suffering upon suffering.”

Traffic, Cockroaches, Mold, and Asthma

Less than a block from where the pope will meet East Harlem families Friday at Our Lady Queen of Angels School, Elizabeth Gonzalez shares a two-bedroom apartment in a public housing project with her three kids ranging in age from 15 to 20.

Cockroaches scurry across the walls and floor. She’s tried to get rid of them, but they keep coming back—through the electric outlets and from under the sink, where leaking pipes create a black sludge. Her floor is wet, her walls damp and moldy. Garbage bags stacked in the living room keep the family's possessions dry.

Gonzalez thumbs through a notebook full of unresolved maintenance requests for her home. It takes months for the New York City Housing Authority to respond to such requests. Often maintenance workers don’t come when they say they’re going to come, even after she’s taken the day off work. And when they do finally show up, they offer little help, she says.

Everyone in her family has asthma. Cockroaches and mold trigger attacks.

“I’m happy to have a roof over my head, but this apartment is keeping us sick,” says Gonzales, a grade school assistant teacher who makes only $26,000 a year.

“People feel trapped. They hold on to these awful apartments, because it’s all they have. It’s their home, their community,” says Ray Lopez, director of environmental health and family asthma for LSA Family Health Service, a nonprofit that serves more than 7,000 East Harlem residents, including Gonzalez and Smith.

View Images Arelys Espinoza, 14, holds her one-year-old brother, Joseph, in their family’s apartment in East Harlem. Their father says the apartment is plagued with problems, including a broken stove that the landlord won’t fix.

LSA was founded by the Little Sisters of the Assumption, a religious order of nuns that provides health services to poor families around the world. Pope Francis’ own family sought help from the Little Sisters of the Assumption in Barrio de Flores, the working-class Buenos Aires neighborhood where he grew up.

José Espinoza, who has a daughter with asthma, gets family health services through LSA. Under the canopy of his Second Avenue flower stand, Espinoza wraps a bouquet of sunflowers and describes the poor conditions of his sixth-floor walk-up apartment. It’s infested with cockroaches and bedbugs, and he worries that allergies to the insects trigger his daughter's asthma attacks and make his other children sick.

Espinoza says in Spanish that it’s becoming too expensive for him to feed his five kids. He explains that the landlord refuses to fix the stove. They’ve been without gas for nearly five months, and it’s difficult for them to cook nutritious meals on an electric hot plate, so they’ve been eating a lot of fast food.

He’s fighting hard to stay in the neighborhood, which he says has good schools, but the housing problems aren’t easing up. Espinoza hopes that the pope’s visit will spur more people to help.

At her home in East Harlem, Smith pulls back a window curtain to reveal glass blackened on the outside by mold and dust. Construction scaffolding blocks out the remaining sunlight.

The avenues that flank the block of public housing where she lives carry a constant procession of exhaust-belching taxis, buses, cars, ambulances, and sanitation trucks. Inside the apartment, paint peels off the buckling drywall. Leaky pipes feed the panels with constant moisture.