More than 132 million Americans live in areas that ought to receive a flunking grade for their dangerously high smog levels, according to an American Lung Association report released today. The report graded metropolitan areas based on the number of days they had unhealthy smog levels in 1996, 1997, and 1998, the most recent years for which EPA figures were available. The most at-risk metropolitan areas included Los Angeles, Houston, Phoenix, St. Louis, and Baltimore-Washington. Among the metro areas that merited an “A” in the report, only Honolulu had a population greater than half a million.