Tobacco

Tobacco is a product prepared from the leaves of the tobacco plant by curing them. The plant is categorized within the genus Nicotiana of the Solanaceae (nightshade) family. While there are more than 70 species of tobacco, the chief commercial crop is N. tabacum. The more potent species N. rustica is also widely used around the world. Tobacco contains the alkaloid nicotine, a stimulant. Dried tobacco leaves are mainly smoked in cigarettes, cigars, pipe tobacco and flavored shisha tobacco. They are also consumed as snuff, chewing tobacco and dipping tobacco.

      Tobacco use is a risk factor for many diseases, especially those affecting the heart, liver and lungs, and several cancers. In 2008, the World Health Organization (WHO) named tobacco as the world's single greatest cause of preventable death.

The English word tobacco originates from the Spanish and Portuguese word tabaco. The precise origin of the Spanish/Portuguese word is disputed but it generally thought to have originated, at least in part, from Taino, the Arawakan language of the Caribbean. In Taino, it was said to refer either to a roll of tobacco leaves (according to Bartolomé de las Casas, 1552), or to the tabago, a kind of Y-shaped pipe for sniffing tobacco smoke (according to Oviedo; with the leaves themselves being referred to as cohiba).

However, similar words in Spanish, Portuguese and Italian were commonly used from 1410 to define medicinal herbs which are believed to have originated from the Arabic طبق tabbaq, a word reportedly dating to the 9th century, as the name of various herbs.

Production of tobacco leaf increased by 40% between 1971, during which 4.2 million tons of leaf were produced, and 1997, during which 5.9 million tons of leaf were produced. According to the Food and Agriculture organization of the UN, tobacco leaf production was expected to hit 7.1 million tons by 2010. This number is a bit lower than the record high production of 1992, during which 7.5 million tons of leaf were produced.

 The production growth was almost entirely due to increased productivity by developing nations, where production increased by 128%. During that same time period, production in developing countries actually decreased. China's increase in tobacco production was the single biggest factor in the increase in world production. China's share of the world market increased from 17% in 1971 to 47% in 1997. This growth can be partially explained by the existence of a high import tariff on foreign tobacco entering China. While this tariff has been reduced from 64% in 1999 to 10% in 2004, it still has led to local, Chinese cigarettes being preferred over foreign cigarettes because of their lower cost.

The harms caused by using tobacco include diseases affecting the heart and lungs, with smoking being a major risk factor for heart attacks, strokes, chronic obstructive pulmonary disease (COPD), emphysema, and cancer (particularly lung cancer, cancers of the larynx and mouth, and pancreatic cancers).

Inhaling secondhand tobacco smoke can cause lung cancer in nonsmoking adults. In the United States, approximately 3,000 adults die each year due to lung cancer from secondhand smoke exposure. Heart disease caused by secondhand smoke kills approximately 46,000 nonsmokers every year.

The addictive alkaloid nicotine is a stimulant, and popularly known as the most characteristic constituent of tobacco. Users may develop tolerance and dependence. Thousands of different chemicals in cigarette smoke, including polycyclic aromatic hydrocarbons (such as benzopyrene), formaldehyde, cadmium, nickel, arsenic, tobacco-specific nitrosamines (TSNAs), phenols, and many others contribute to the harmful effects of smoking.

 

Tobacco smoking is the practice of burning tobacco and inhaling the smoke (consisting of particle and gaseous phases). (A more broad definition may include simply taking tobacco smoke into the mouth, and then releasing it, as is done by some with tobacco pipes and cigars.) The practice was believed to begin as early as 5000–3000 BC . Tobacco was introduced to Eurasia in the late 17th century where it followed common trade routes. The practice encountered criticism from its first import into the Western world onwards, but embedded itself in certain strata of a number of societies before becoming widespread upon the introduction of automated cigarette-rolling apparatus.

German scientists identified a link between smoking and lung cancer in the late 1920s, leading to the first anti-smoking campaign in modern history, albeit one truncated by the collapse of the Third Reich at the end of the Second World War. In 1950, British researchers demonstrated a clear relationship between smoking and cancer. Evidence continued to mount in the 1980s, which prompted political action against the practice. Rates of consumption since 1965 in the developed world have either peaked or declined. However, they continue to climb in the developing world.

Smoking is the most common method of consuming tobacco, and tobacco is the most common substance smoked. The agricultural product is often mixed with additives and then combusted. The resulting smoke is then inhaled and the active substances absorbed through the alveoli in the lungs. Combustion was traditionally enhanced by addition of potassium or other nitrates. Many substances in cigarette smoke trigger chemical reactions in nerve endings, which heighten heart rate, alertness, and reaction time, among other things. Dopamine and endorphins are released, which are often associated with pleasure. As of 2008 to 2010, tobacco is used by about 3 billion people (about 49% of men and 11% of women) with about 80% of this usage in the form of smoking. The gender gap tends to be less pronounced in lower age groups.

Many smokers begin during adolescence or early adulthood. During the early stages, a combination of perceived pleasure acting as positive reinforcement and desire to respond to social peer pressure may offset the unpleasant symptoms of initial use, which typically include nausea and coughing. After an individual has smoked for some years, the avoidance of withdrawal symptoms and negative reinforcement become the key motivations to continue.

In a study done by Jennifer O' Loughlin and her colleagues, the first smoking experiences of seventh-grade students were studied. They found out that the most common factor leading students to smoke is cigarette advertisements. Smoking by parents, siblings and friends also encourage students to smoke.