About one-third of Philadelphia’s garbage goes to a facility in Chester, Pa. where it’s burned and converted into energy. But that incinerator also pollutes the air Chester residents breathe and researchers say it’s one of the dirtiest in the U.S. WHYY’s Catalina Jaramillo explains why the city continues to send its trash there — and why many incinerators like this one are located in low-income communities of color.