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.
On a Urine Drug Test, THC will appear as a positive within 2-5 hours of use. How long it will still show on a urine drug test is estimated based on frequency of use, but does not take into account the weight and body fat of the marijuana user:1  One Time User may show positive for 1-6 days. 2  Moderate User may show positive for 7-13 days.n a Hair Drug Test, THC will show up about 7 days after use and most hair drug tests will test for a 90 day period. However, THC does not always bind to the hair follicle which makes it not always considered an accurate testing method for marijuana use.