In New York City, air pollution is unevenly distributed among the city’s neighborhoods, often in surprising ways, according to datafrom the New York City Department of Health, which tracks several air pollutants across time and geography.

The city’s air is a diffuse soup of suspended particles, the byproducts of everyday activities like cooking food, driving cars and buses, and the construction and heating of buildings. Tire and road wear contribute too, so electric vehicles are not off the hook.

The most common measure of air pollution is fine particulate matter (PM2.5), the concentration of particles smaller than 2.5 micrometers, small enough to be easily inhaled and make their way into the human body.

High levels of PM2.5 and its smoggy sibling, ozone — formed when emissions interact with sunlight — are linked to many deleterious health outcomes, according to the department.

“Exposure to particulate matter has been linked to breathing problems, reduced lung function, heart disease and premature death,” the department states, while ozone “causes irritation and inflammation of the lungs and worsening of asthma.”

Social and economic interaction are also constrained by high levels of air pollution when sensitive people stay indoors to avoid it.

Given New York’s density and the migratory nature of pollution, there isn’t a neat relationship between wealthy neighborhoods, cleaner air and health. Heavy traffic, buildings and commercial cooking help make Midtown Manhattan and five areas of the borough south of it the most polluted by PM2.5, as shown on this week’s chart.

Pollutants and their impacts often show up in local health data. The Rockaways, with the city’s highest ozone levels because of its location downwind from emissions sources in the denser parts of the city, have an above-average rate of preterm births and asthma-related emergency department visits.

Though New York has made remarkable progress. Between 2009 and 2024, all boroughs have experienced a substantial reduction in average annual PM2.5, around 40 percent, achieved largely because of city regulations requiring reduced building emissions. Ozone — partially a function of global warming — remains stubborn.

Read More: The New York Times