When it comes to a question of air pollution, Philly ranks high and rates low.
The city’s larger metropolitan area—meaning northern Delaware and parts of New Jersey, as well as Philly—received an F rating in a 2018 State of the Air report published by the American Lung Association, which examined ground-level ozone across the country according to PhillyMag.
For the report, the ALA surveyed 227 cities. Philly was one of those with a higher average of unhealthy days in 2014-2016 than other cities, according to the ALA. Philly ranked 12th for particle pollution year-round and 24th for days with high ozone pollution, the ALA said.
Ground-level ozone—also known as smog—is created by toxins from cars, power plants, refineries and other sources, according to the Environmental Protection Agency. It can affect the health of everyday citizens, but primarily people who have asthma, the elderly, children and outdoor workers.