HealthDay: A new study from Denmark says long-term exposure to low levels of air pollution could increase the risk of developing severe chronic obstructive pulmonary disease (COPD). Previous research has found a link between high levels of air pollution and exacerbation of COPD, but this study connects long-term air pollution exposure to the development or progression of the lung disease, according to the researchers. “Our findings have significance on a number of levels — patients, …