Detroit’s air quality ranked among the worst in the U.S. on Friday morning following the Fourth of July holiday fireworks use, posing “very unhealthy” conditions for children, seniors and people with certain health conditions who went outdoors. Detroit’s air quality ranked among the worst in the U.S. on Friday morning following the Fourth of July holiday fireworks use, posing “very unhealthy” conditions for children, seniors and people with certain health conditions who went outdoors. Environment Phys.org – latest science and technology news stories