ScienceDaily: People with heart disease face an increased risk of a serious heart attack during poor air quality days, according to a major new study presented today at the American Heart Association Scientific Session in Orlando. The study of more than 16,000 patients by researchers at the Intermountain Medical Center Heart Institute in Salt Lake City examined patients who had suffered three types of heart attacks -- STEMI, non-STEMI, and unstable angina -- to identify which type of heart attack was more likely...