In the anatomical model, researchers believe that the absence of the cervical mucous plug, which is normally there during the menstrual cycle, allows air to pass from the genital tract to the pleural space through fenestrations in the diaphragm. Another theory is that hormonal changes that come with the menstrual cycle can cause blebs to spontaneously rupture. Blebs are small blisters/pustules filled with air or fluid and can develop on the lungs.Endometrial tissue attaches within the thoracic cavity, forming chocolate-like cysts. Generally the parietal pleura is involved, but the lung itself, the visceral layer, the diaphragm, and more rarely the tracheobronchial tree may also be afflicted. The mechanism through which endometrial tissue reaches the thorax remains unclear. Nearly 90% of cases occur on the right hemithorax, a phenomenon thought to potentially be due to the direction of flow of retroperitoneal fluid. Peritoneal flow occurs in a clockwise pattern, which could likely explain the tendency for catamenial pneumothoraces to be right-sided. Defects in the diaphragm, which are found often in affected individuals, could provide an entry path, as could microembolization through pelvic veins. Such diaphragmatic defects may be either congenital or acquired. The cysts can release blood; the endometrial cyst "menstruates" in the lung. Endometrial cells undergo structural changes during the secretory phase of the menstrual cycle, in a process called decidualization. Decidualized pleural endometrial implants can disrupt the pleura and lead to pneumothorax (and hemothorax). Diagnosis
Diagnosis can be hinted by high recurrence rates of lung collapse in a woman of reproductive age with endometriosis.
The trend has been paralleled by many industrialized nations as rates have either leveled-off or declined. In the developing world, however, tobacco consumption continues to rise at 3.4% in 2002. In Africa, smoking is in most areas considered to be modern, and many of the strong adverse opinions that prevail in the West receive much less attention. Today Russia leads as the top consumer of tobacco followed by Indonesia, Laos, Ukraine, Belarus, Greece, Jordan, and China.As a result of public pressure and the FDA, Walmart and Sams club announced that they were raising the minimum age to purchase tobacco products, including all e-cigarettes, to 21 starting  1 July 2019. Consumption
Methods
Tobacco is an agricultural product processed from the fresh leaves of plants in the genus Nicotiana. The genus contains several species, of which Nicotiana tabacum is the most commonly grown. Nicotiana rustica follows second, containing higher concentrations of nicotine. The leaves are harvested and cured to allow the slow oxidation and degradation of carotenoids in tobacco leaf. This produces certain compounds in the tobacco leaves which can be attributed to sweet hay, tea, rose oil, or fruity aromatic flavors. Before packaging, the tobacco is often combined with other additives in order to increase the addictive potency, shift the products pH, or improve the effects of smoke by making it more palatable. In the United States these additives are regulated to 599 substances. The product is then processed, packaged, and shipped to consumer markets.