Bad air quality poses a particular risk to children with asthma. In unequal Philly, those kids are mostly Black and Hispanic.

Smoke from wildfires in Canada made Wednesday, the most unhealthy day for air quality the city has experienced since 2008, especially risky to children with asthma. And in Philadelphia, Black and Hispanic children are much likelier to develop asthma — and to get sicker from it.

» READ MORE: Your health questions about Philadelphia’s worst air quality day in a decade, answered

As the chief of the emergency department at St. Christopher’s Hospital for Children in North Philadelphia, James Reingold often sees kids struggling to breathe as they cross his hospital’s doorstep. Children in the neighborhoods around the hospital have some of the highest rates of asthma in the city.

“That’s not because Hispanic and Black children have an inherent difference in how they respond to asthma,” Reingold said. “It’s just a marker for where they live, what pollution they’re exposed to and what other chronic stress they’re under.”

On Wednesday, Reingold was preparing for what he feared would be an influx of patients affected by the smoke. Just the day before, a child had collapsed in his emergency department and nearly died, he said.

“It was unusual — possibly a warning sign for what the next few days are going to be like,” he said. “We have so many children who have asthma, and the asthma they have is so, so high. I’ve never seen such a sick cohort of children.”

Parents of kids with asthma living in the North Philadelphia neighborhoods around St. Christopher’s were also watching the skies with concern Wednesday afternoon.

In the hospital parking lot, Hawa Dawleit’s 7-year-old son begged his mom to take him to a nearby park after a routine doctor’s appointment.

“Pleaseeeeee,” he implored.

”No, the air is bad,” she told him. “We’re going home now.”

Her son, Lugman Fadalla, a first grader at Juniata Park Academy, has severe asthma. It typically flares up in winter months, but the smoke threatened to ruin the reprieve he enjoys in late spring and summer, Dawleit said, speaking in Arabic with her oldest daughter translating. Her son wasn’t experiencing asthma symptoms, at least not yet, and she wanted to keep him stable, she said.

Dawleit took her children to the park on Tuesday, but a combination of rain and poor air quality drove them indoors.

”We’re not allowed to go outside because of the condition of the air,” explained Lugman’s older sister, Rayan Mohmaed Fadalla, 11. “My mom gets a little scared. We’re lucky the hospital is nearby.”

Asthma is a condition in which the tubes in the lungs narrow in response to certain allergens or toxins. This causes symptoms like wheezing and difficulty breathing.

In extreme cases, the lung’s tubes can shut within seconds or minutes, said Daniel Taylor, a pediatrician at St. Christopher’s. For many kids, it can take a couple of days for the inflammation to build up and have an impact on breathing.

If untreated, the consequences can be deadly.

Typically, children that end up seeking treatment at St. Christopher’s have seen their asthma exacerbated by environmental toxins like mold, pollutants from cars and factories, and sparse tree coverage, which all increase the risk for asthma, Taylor said.

» READ MORE: How will the smoke change in Philly over time? Here’s a look at the air quality forecast for the region.

As the poorest large city in America, Philadelphia has a pediatric asthma rate that is roughly three times that of the national average.

Children in the majority-Black neighborhoods of North Philadelphia, Nicetown, West Philadelphia and Kingsessing have some of the city’s highest asthma hospitalization rates, according to an Inquirer analysis of hospital cost data.

Overall, Black children 19 and younger are hospitalized due to asthma at a rate five times that of their white counterparts, The Inquirer found.

Today’s health disparities are among the consequences of redlining, racist housing policies that confined Black and Hispanic residents to neighborhoods bisected by highways and other structures like power plants that produce pollution.

Experts call the area around St. Christopher’s a perfect storm for childhood asthma.

To the east of the neighborhood, there’s I-95, the interstate that’s regularly clogged with stop-and-go traffic. “We know from many studies that proximity to a major interstate is directly correlated to terrible respiratory health,” Reingold said.

To the west runs Broad Street, the city’s main thoroughfare. To the north is busy Roosevelt Boulevard. The neighborhood also houses a power plant. And the housing stock, Reingold said, is some of the most dilapidated in the city, with homes more prone to chronic mold and other irritants.

“It starts with poor housing,” said Tyra Bryant-Stephens, chief health equity officer at Children’s Hospital of Philadelphia and the director and founder of its Community Asthma Prevention Program. “There are historical injustices with redlining, and also with having the ability to achieve wealth and keep a home repaired.”

» READ MORE: Philadelphia School District orders students to stay inside, cancel field trips

She and other doctors who work with kids with asthma have been fielding questions from concerned parents about this week’s wildfire smoke — and the longer-term challenges that it represents.

The top priority for preventing asthma, Bryant-Stephens said, is “having healthy housing and healthy schools so kids aren’t chronically exposed to allergens and irritants.”

Khalil Savary, a pediatric pulmonologist at Rutgers University Hospital in Newark, said this week’s events illustrate how certain environmental issues disproportionately affect more vulnerable Americans.

“We have constant reminders that we are subject to weather events,” he said. “It’s a call to action to help raise the bar of health.”