What effect does marijuana have on your lungs?

Some say that marijuana is linked to lung cancer. Is this really true? To what extent and effect does marijuana have on the lungs? "There are also negative effects on the lungs that the tars and resins of marijuana can cause, particularly when it is mixed with tobacco. It has been proven that smoking marijuana can and will contribute to illnesses or disorders such as asthma and pulmonary emphysema. Although no known cases of death have been causal to smoking marijuana, it has been theorized that some types of cancer originate due to agitation of the body alone. Because marijuana users often inhale the unfiltered smoke deeply and then hold it in their lungs as long as possible, chronic marijuana use may play a role in the development of chronic respiratory problems"(HealthBlurtIt). According to the Huff Post, "Smoking a joint once a week or a bit more apparently doesn't harm the lungs, suggests a 20-year study that bolsters evidence that marijuana doesn't do the kind of damage tobacco does.
The results, from one of the largest and longest studies on the health effects of marijuana, are hazier for heavy users – those who smoke two or more joints daily for several years. The data suggest that using marijuana that often might cause a decline in lung function, but there weren't enough heavy users among the 5,000 young adults in the study to draw firm conclusions". The Huff Post goes on to say, "
The findings echo results in some smaller studies that showed while marijuana contains some of the same toxic chemicals as tobacco, it does not carry the same risks for lung disease.
It's not clear why that is so, but it's possible that the main active ingredient in marijuana, a chemical known as THC, makes the difference. THC causes the "high" that users feel. It also helps fight inflammation and may counteract the effects of more irritating chemicals in the drug, said Dr. Donald Tashkin, a marijuana researcher and an emeritus professor of medicine at the University of California, Los Angeles. Tashkin was not involved in the new study. Study co-author Dr. Stefan Kertesz said there are other aspects of marijuana that may help explain the results". This study did not focus or examine lung cancer. Another study from the United Kingdom suggests that, Habitual marijuana use may lead to the following effects on the lung: 

• acute and chronic bronchitis;
• extensive microscopic abnormalities in the cells lining the bronchial passages (bronchial epithelium), some of which may be premalignant;
• overexpression of genetic markers of progression to lung cancer in bronchial tissue;
• abnormally increased accumulation of inflammatory cells (alveolar macrophages) in the lung; and
• impairment in the function of these immune-effector cells (reduced ability to kill microorganisms and tumor cells) and in their ability to produce protective inflammatory cytokines.   

 There are many studies on Marijuana use. It is definitely illegal in the United States.The main thing that should be taken from this is if you use marijuana habitually, your chances of damaging your body are higher and your more at risk for illnesses and disorders which can lead to chronic respiratory problems. More studies and research are underway.

References:
 "How Does Marijuana Affect You And Your Lungs?" Blurt It. N.p., n.d. Web. 11
     Dec. 2013. <http://diseases-conditions.blurtit.com/114417/
     how-does-marijuana-affect-you-and-your-lungs>.
Tanner, Lindsey. "Marijuana And Lungs: Study Finds Drug Doesn't Do Same Kind Of
     Damage As Tobacco." Huff Post: San Francisco. N.p., 10 Jan. 2012. Web. 11
     Dec. 2013. <http://www.huffingtonpost.com/2012/01/10/
     marijuana-and-lungs-study_n_1197854.html>. 
Tashkin, Donald P. "Effects of marijuana on the lung and its immune defenses."
     UKCIA. N.p., n.d. Web. 11 Dec. 2013. <http://www.ukcia.org/
     research/EffectsOfMarijuanaOnLungAndImmuneDefenses.php>.


 Rachael S.W.