In the age of technology it is easy to find a meme with information on it that may be very misleading. With that idea in mind if you see information that could be wrong its always good to double check and learn a little more to know for sure fact vs fiction!
The American Lung Association (ALA) does note that marijuana smoke contains four times as much tar and tobacco-based cigarette smoke:
However, although it may be true that marijuana smoke deposits more tar into a smoker’s lungs than tobacco smoke, the above-displayed photograph does not accurately depict the difference in overall harm caused to a tobacco smoker’s lungs versus a marijuana smoker’s lungs. Marijuana contains many of the same cancer-causing chemicals as tobacco smoke, but a recent study found no link between marijuana and an increased risk of lung cancer. According to Dr. Hal Morgenstern, a University of Michigan epidemiologist, this factor was likely attributable to the differences between marijuana and tobacco use:
However, a study funded by the National Institute on Drug Abuse found that even heavy marijuana smokers did not have an increased risk of developing lung cancer:
Donald Tashkin, a UCLA pulmonologist who has studied marijuana for 30 years, hypothesized that the chemical THC may prevent the cancer-causing chemicals in marijuana smoke from negatively affecting the body:
The THC in marijuana has well-defined anti-tumoral effects that have been shown to inhibit the growth of a variety of cancers in animal models and tissue culture systems, thus counteracting the potentially tumorigenic effects of the procarcinogens in marijuana smoke.
We don’t know for sure & but a very reasonable possibility is that THC may actually interfere with the development of chronic obstructive pulmonary disease.
In conclusion, although it may be true that marijuana smoke deposits more tar into the lungs than tobacco smoke, current evidence does not indicate that the former results in proportionally greater deleterious health affects.
Source – Snopes