I might as well share some other sections. Here is the link to the entire section, you can see a few parts without a subscription and the list of Sources.

Pulmonary — Cannabis smoke contains many of the same combusted particles found in tobacco smoke [31]. As an example, cannabis smoke contains approximately three times the amount of tar found in tobacco smoke and 50 percent more carcinogens [32]. In addition, hand rolled cannabis cigarettes are not filtered and the smoke is inhaled deeply [1]. However, individuals typically smoke far less cannabis than tobacco.

Cannabis smoke irritates the airways and is associated with cough, sputum production, wheezing, bronchodilatation, and bronchitis, as well as dyspnea, pharyngitis, exacerbation of asthma, and exacerbation of cystic fibrosis [31]. An epidemiologic survey of a nationally representative US sample found that cannabis smokers have significantly higher rates of chronic inflammatory changes compared to those who do not smoke, after controlling for sex, age, current asthma, and tobacco use [33]. Longer-term use is associated with increased respiratory symptoms suggestive of obstructive lung disease [31].

Long-term cannabis smoking has not been found to be associated with measures of pulmonary function or airflow obstruction [31]. As an example, a longitudinal study of 5,115 people over a 20-year period found that occasional and low, cumulative cannabis use was not associated with reduced pulmonary function (forced expiratory volume and forced vital capacity) [34].

Cancer — Molecular, cellular, and histopathological evidence indicate that cannabis smoking may cause cancer [35,36], though research is inconclusive [35]. Many methodologic problems of existing studies, such as inadequate sample sizes and not accounting for important confounding factors, especially cigarette smoking, limit the ability to detect an association.

●Lung cancer — Cannabis smokers are probably at increased risk for lung cancer; the magnitude of risk has not been well quantified [37]. (See "Cigarette smoking and other risk factors for lung cancer", section on 'Marijuana and cocaine'.)

●Head and neck cancer — A pooled analysis of five case control studies did not find an association between cannabis use and cancer of the head and neck [38]. (See "Epidemiology and risk factors for head and neck cancer", section on 'Smoking'.)

●Bladder cancer — A case control study found that patients with transitional cell carcinoma of the bladder were significantly more likely to be habitual cannabis users, compared to the controls without transitional cell carcinoma (89 versus 69 percent) [39]. However, the clinical significance of this finding is unclear, especially in light of the fact that tobacco use was a potential confounding variable. (See "Epidemiology and etiology of urothelial (transitional cell) carcinoma of the bladder".)