Bronx Air Pollution and Asthma: How Summer Smog Deepens Health Disparities

For Bronx residents, summer means more than just heat — it can carry hidden hazards that put respiratory health at risk.

But the impact isn’t felt equally across the borough.

Two pollutants are most commonly associated with air quality: ground-level ozone and PM2.5 — tiny particles that can harm the lungs.

With asthma rates among the highest in the city, Bronxites are more vulnerable to particle exposure, which can trigger attacks and make breathing difficult.

“New York City’s pollution basically cooks in the summer,” explained George Thurston, a New York University professor and leading researcher on air pollution’s health effects. 

According to the city’s department of health and mental hygiene, the concentration of PM2.5 in the air between Riverdale–Spuyten Duyvil and Hunts Point increased by a full point, from 6.7 micrograms per cubic meter to 7.7.

This is largely driven by industrial manufacturing and dense traffic. Outdoor air pollution tends to be higher near highways or areas with commuter and truck congestion, such as the Cross Bronx Expressway or the Bruckner Expressway — both running through the southern Bronx.

The city’s 2023 health report detailed about 48 of every 10,000 emergency department visits involved adults with asthma in the Kingsbridge–Riverdale area — four times less than the 194 of every 10,000 in Hunts Point–Mott Haven.

“The traffic particles are really very damaging and cause inflammation,” said Thurston. “The diesel particles induce an allergic reaction of their own … IgA [a type of antibody that fights infections] levels go up in the blood, so the bodies of people with asthma and allergies will react just to the diesel.”

When the Air Quality Index, or AQI, is poor due to heat waves, smog or national events such as the 2023 Canadian wildfires, the impact is widespread across the borough — highlighting disparities in which communities receive adequate care.

Dr. Krystal Cleven, pulmonary co-director of the Montefiore Asthma Center, said she hasn’t seen a notable increase in patients this summer compared to previous years. But she pointed out some residents are more vulnerable when pollution rises.

“[Lower-income areas] tend to correlate with poor baseline health, poor access to health, not having the asthma care that they need at baseline, all those things,” said Cleven. “Those areas aren’t the areas with the worst pollution levels, generally speaking, it’s just that when the levels go up — it’s not going to be someone who lives on Park Avenue who’s going to fare worse.”

Ninety-four percent of adults in Kingsbridge–Riverdale have health insurance — 11 percent higher than in the South Bronx. 

Similarly, there is a 17-percentage-point gap in adults with a personal doctor, and an 11-point gap in those reporting good or excellent health. 

Cleven said she urges her patients to be as aware of indoor air quality as they are outdoors. On some days, when the AQI is low, pollutants that worsen asthma — including roaches, mice, mold and smoke or secondhand smoke — are just as severe.

State programs such as Healthy Homes and School Environmental Health, along with nonprofits like South Bronx Unite, are working to combat risks, especially in neighborhoods with fewer resources.

Despite barriers, Cleven emphasized small changes within residents’ control: taking inhalers as prescribed, monitoring the AQI and communicating with landlords to avoid indoor triggers.