They are important for lung function, since their purpose is the exchange of oxygen and carbon dioxide. When the airways are blocked by a mucous plug, foreign object, or tumor, the alveoli are unable to fill with air and collapse of lung tissue can occur in the affected area.
Testing Positive for Marijuana Does Not Indicate Impairment Someone can test positive for marijuana days or even weeks after they last used it. by Dr. Carl Hart @drcarlhart. AAs Oregonians consider their vote on tax and regulation of marijuana, it is important for them to have access to sound information grounded in science.
If a patient does test positive, you need to take a careful medical history, Smith said. Smith also did some myth-busting, finding that there's no possibility of a false positive resulting from passive inhalation of marijuana or cocaine -- unless they are exposed to an excessively concentrated amount of smoke.