“Marijuana smoked, like tobacco smoked, contains toxins and other foreign particulates that are known to cause inflammation in the lining of the lungs. Unlike tobacco smoke, marijuana smoke substantially reduced the alveolur macrophages, the lung’s primary defense against infectious microorganisms, foreign substances and tumor cells.
This is of particular concern for the immunocompromised HIV/ AIDS patients or cancer patient, who is already at great risk for opportunistic lung infections. Though the evidence is no means conclusive, chronic marijuana smoking may be a factor in the development of acute and chronic bronchitis, and increasing the risk of pneumonia.”Feb. 26, 2007