CHICAGO—Highlighting increasingly dangerous conditions within the city, a new study published Monday by Northwestern University’s Department of Environmental Studies revealed that approximately 75 percent of the air in Chicago is now composed of bullets. “Far exceeding the levels of carbon dioxide, nitrogen, and even oxygen, bullets now constitute three-fourths of Chicago’s air supply,” said atmospheric scientist and study coauthor John Molina, stressing that the dense and widespread deposits of jacketed lead and copper in the air pose severe and potentially fatal health risks to all Chicago residents. “According to our measurements, the proportion of bullets in Chicago’s overall air composition is significantly higher than that of other cities with comparable sizes and population densities. Frankly, if this trend continues—and there is unfortunately little evidence suggesting otherwise—living safely within the confines of Chicago will be almost impossible.” Molina went on to suggest that Chicago’s 2.7 million residents stay indoors whenever possible in order to minimize their exposure.