SOMKING- CIGARATTE AND IT EFFECT

A cigarette is a small cylinder of finely cut tobacco leaves rolled in thin paper for smoking. The cigarette is ignited at one end causing the cigarette to smoulder and allowing smoke to be inhaled from the other end, which is held in or to the mouth; in some cases, a cigarette holder may be used, as well. Most modern manufactured cigarettes are filtered, and also include reconstituted tobacco and other additives.

The term cigarette, as commonly used, refers to a tobacco cigarette but can apply to similar devices containing other substances, such as a cannabis cigarette. A cigarette is distinguished from a cigar by its smaller size, use of processed leaf, and paper wrapping, which is normally white, though other colors and flavors are also available. Cigars are typically composed entirely of whole-leaf tobacco.

Rates of cigarette smoking vary widely throughout the world and have changed considerably since cigarettes were first widely used in the mid-19th century. While rates of smoking have over time leveled off or declined in the developed world, they continue to rise in developing nations.

Nicotine, the primary psychoactive chemical in tobacco and therefore cigarettes, is very addictive. About half of cigarette smokers die of tobacco-related disease and lose on average 14 years of life. Cigarette use by pregnant women has also been shown to cause birth defects, including low birth weight, fetal abnormalities, and premature birth.Second-hand smoke from cigarettes has been shown to be injurious to bystanders,which has led to legislation that has prohibited smoking in many workplaces and public areas. The smoke produced is an aerosol containing over 4,000 distinct chemical compounds, including nicotine, carbon monoxide and acrolein. Over 50 of these are carcinogenic.Cigarettes are a frequent source of house fires, which prompted both the European Union and the United States to ban cigarettes that are not fire-standard compliant from 2011 onwards.

Smoking restrictions

Many governments impose restrictions on smoking tobacco, especially in public areas. The primary justification has been the negative health effects of second-hand smoke. Laws vary by country and locality. Bhutan is currently the only country in the world to completely outlaw the cultivation, harvesting, production, and sale of tobacco and tobacco products under the Tobacco Control Act of Bhutan 2010. However, small allowances for personal possession are permitted as long as the possessors can prove that they have paid import duties The Pitcairn Islands had previously banned the sale of cigarettes, but it now permits sales from a government-run store. The Pacific island of Niue hopes to become the next country to prohibit the sale of tobacco. Iceland is also proposing banning tobacco sales from shops, making it prescription-only and therefore dispensable only in pharmacies on doctor's orders.[33] New Zealand hopes to achieve being tobacco-free by 2025 and Finland by 2040. Singapore and the Australian state of Tasmania have proposed a 'tobacco free millennium generation initiative' by banning the sale of all tobacco products to anyone born in and after the year 2000. In March 2012, Brazil became the world's first country to ban all flavored tobacco including menthols. It also banned the majority of the estimated 600 additives used, permitting only eight. This regulation applies to domestic and imported cigarettes. Tobacco manufacturers have 18 months to remove the noncompliant cigarettes, 24 months to remove the other forms of noncompliant tobacco. Under sharia law, the consumption of cigarettes by Muslims is prohibited. In the Islamic State of Iraq and the Levant the consumption, and even its possession is illegal.

Smoking age

Beginning on April 1, 1998, the sale of cigarettes and other tobacco products to people under the state purchase age has been prohibited by law in all 50 states of the United States. The purchasing age in the United States is 18 in 44 of the 50 states — but 19 in Alabama, Alaska, Utah, and Nassau, Suffolk, and Onondaga Counties in New York,and 21 in California, Hawaii, and New Jersey and more than 180 municipalities across the nation. The intended effect of this is to prevent older high school students from purchasing cigarettes for their younger peers. In Massachusetts,parents and guardians are allowed to give cigarettes to minors, but sales to minors are prohibited.

Similar laws exist in many other countries. In Canada, most of the provinces require smokers to be 19 years of age to purchase cigarettes (except for Quebec and the prairie provinces, where the age is 18). However, the minimum age only concerns the purchase of tobacco, not use. Alberta, however, does have a law which prohibits the possession or use of tobacco products by all persons under 18, punishable by a $100 fine. Australia, New Zealand, Poland, and Pakistan have a nationwide ban on the selling of all tobacco products to people under the age of 18.

Tabak-Trafik in Vienna: Since 1 January 2007, all cigarette machines in Austria must attempt to verify a customer's age by requiring the insertion of a debit card or mobile phone verification.
Since 1 October 2007, it has been illegal for retailers to sell tobacco in all forms to people under the age of 18 in three of the UK's four constituent countries (England, Wales, Northern Ireland, and Scotland) (rising from 16). It is also illegal to sell lighters, rolling papers, and all other tobacco-associated items to people under 18. It is not illegal for people under 18 to buy or smoke tobacco, just as it was not previously for people under 16; it is only illegal for the said retailer to sell the item. The age increase from 16 to 18 came into force in Northern Ireland on 1 September 2008. In the Republic of Ireland, bans on the sale of the smaller 10-packs and confectionery that resembles tobacco products (candy cigarettes) came into force on May 31, 2007, in a bid to cut underaged smoking.

Most countries in the world have a legal vending age of 18. In Macedonia, Italy, Malta, Austria, Luxembourg, and Belgium, the age for legal vending is 16. Since January 1, 2007, all cigarette machines in public places in Germany must attempt to verify a customer's age by requiring the insertion of a debit card. Turkey, which has one of the highest percentage of smokers in its population,has a legal age of 18. Japan is one of the highest tobacco-consuming nations, and requires purchasers to be 20 years of age (suffrage in Japan is 20 years old). Since July 2008, Japan has enforced this age limit at cigarette vending machines through use of the taspo smart card. In other countries, such as Egypt, it is legal to use and purchase tobacco products regardless of age.[citation needed] Germany raised the purchase age from 16 to 18 on the 1 September 2007.

Some police departments in the United States occasionally send an underaged teenager into a store where cigarettes are sold, and have the teen attempt to purchase cigarettes, with their own or no ID. If the vendor then completes the sale, the store is issued a fine. Similar enforcement practices are regularly performed by Trading Standards officers in the UK, Israel, and the Republic of Ireland.

Construction

Modern commercially manufactured cigarettes are seemingly simple objects consisting mainly of a tobacco blend, paper, PVA glue to bond the outer layer of paper together, and often also a cellulose acetate–based filter. While the assembly of cigarettes is straightforward, much focus is given to the creation of each of the components, in particular the tobacco blend. A key ingredient that makes cigarettes more addictive is the inclusion of reconstituted tobacco, which has additives to make nicotine more volatile as the cigarette burns.

Additives

Various additives are combined into the shredded tobacco product mixtures, with humectants such as propylene glycol or glycerol, as well as flavoring products and enhancers such as cocoa solids, licorice, tobacco extracts, and various sugars, which are known collectively as "casings". The leaf tobacco is then shredded, along with a specified amount of small laminate, expanded tobacco, BL, RL, ES, and IS. A perfume-like flavor/fragrance, called the "topping" or "toppings", which is most often formulated by flavor companies, is then blended into the tobacco mixture to improve the consistency in flavor and taste of the cigarettes associated with a certain brand name. Additionally, they replace lost flavors due to the repeated wetting and drying used in processing the tobacco. Finally, the tobacco mixture is filled into cigarette tubes and packaged.

A list of 599 cigarette additives, created by five major American cigarette companies, was approved by the Department of Health and Human Services in April 1994. None of these additives is listed as an ingredient on the cigarette pack(s). Chemicals are added for organoleptic purposes and many boost the addictive properties of cigarettes, especially when burned.[citation needed]

One of the classes of chemicals on the list, ammonia salts, convert bound nicotine molecules in tobacco smoke into free nicotine molecules. This process, known as freebasing, could potentially increase the effect of nicotine on the smoker, but experimental data suggests that absorption is, in practice, unaffected.

Cigarette tube

Cigarette tubes are prerolled cigarette paper usually with an acetate or paper filter at the end. They have an appearance similar to a finished cigarette, but are without any tobacco or smoking material inside. The length varies from what is known as King Size (84 mm) to 100s (100 mm).

Filling a cigarette tube is usually done with a cigarette injector (also known as a shooter). Cone-shaped cigarette tubes, known as cones, can be filled using a packing stick or straw because of their shape. Cone smoking is popular because as the cigarette burns, it tends to get stronger and stronger. A cone allows more tobacco to be burned at the beginning than the end, allowing for an even flavor.

The United States Tobacco Taxation Bureau defines a cigarette tube as "Cigarette paper made into a hollow cylinder for use in making cigarettes."

Cigarette filter

Simple molecular representation of cellulose acetate with one of the acetate groups on the cellulose backbone shown by the red circle
Cigarette butt

A discarded cigarette butt, lying on dirty snow
See also: Ashtray and Cigarette pack § Features
The common name for the remains of a cigarette after smoking is a cigarette butt. The butt is typically about 30% of the cigarette's original length. It consists of a tissue tube which holds a filter and some remains of tobacco mixed with ash. They are the most numerically frequent litter in the world. Cigarette butts accumulate outside buildings, on parking lots, and streets where they can be transported through storm drains to streams, rivers, and beaches. It is also called a fag-end or dog-end.

In a recent trial the city of Vancouver, British Columbia, partnered with TerraCycle to create a system for recycling of cigarette butts. A reward of 1¢ per collected butt was offered to determine the effectiveness of a deposit system similar to that of beverage containers.

Environmental impact

Cigarette filters are made up of thousands of polymer chains of cellulose acetate, which has the chemical structure shown to the right. Once discarded into the environment, the filters create a large waste problem. Cigarette filters are the most common form of litter in the world, as approximately 5.6 trillion cigarettes are smoked every year worldwide. Of those, an estimated 4.5 trillion cigarette filters become litter every year. To develop an idea of the waste weight amount produced a year the table below was created.

Estimated waste produced from filters
Number of filters weight
1 pack (20) 0.12 ounces (3.4 g)
sold daily (15 billion) 5,625,000 pounds (2,551,000 kg)
sold yearly (5.6 trillion) 2,100,000,000 pounds (950,000,000 kg)
estimated trash (4.5 trillion) 1,687,500,000 pounds (765,400,000 kg)
Discarded cigarette filters usually end up in the water system through drainage ditches and are transported by rivers and other waterways to the ocean.

Aquatic life health concerns

In the 2006 International Coastal Cleanup, cigarettes and cigarette butts constituted 24.7% of the total collected pieces of garbage, over twice as many as any other cAdditives
Various additives are combined into the shredded tobacco product mixtures, with humectants such as propylene glycol or glycerol, as well as flavoring products and enhancers such as cocoa solids, licorice, tobacco extracts, and various sugars, which are known collectively as "casings". The leaf tobacco is then shredded, along with a specified amount of small laminate, expanded tobacco, BL, RL, ES, and IS. A perfume-like flavor/fragrance, called the "topping" or "toppings", which is most often formulated by flavor companies, is then blended into the tobacco mixture to improve the consistency in flavor and taste of the cigarettes associated with a certain brand name. Additionally, they replace lost flavors due to the repeated wetting and drying used in processing the tobacco. Finally, the tobacco mixture is filled into cigarette tubes and packaged.

A list of 599 cigarette additives, created by five major American cigarette companies, was approved by the Department of Health and Human Services in April 1994. None of these additives is listed as an ingredient on the cigarette pack(s). Chemicals are added for organoleptic purposes and many boost the addictive properties of cigarettes, especially when burned.[citation needed]

One of the classes of chemicals on the list, ammonia salts, convert bound nicotine molecules in tobacco smoke into free nicotine molecules. This process, known as freebasing, could potentially increase the effect of nicotine on the smoker, but experimental data suggests that absorption is, in practice, unaffected.[76]

Cigarette tube
Cigarette tubes are prerolled cigarette paper usually with an acetate or paper filter at the end. They have an appearance similar to a finished cigarette, but are without any tobacco or smoking material inside. The length varies from what is known as King Size (84 mm) to 100s (100 mm).

Filling a cigarette tube is usually done with a cigarette injector (also known as a shooter). Cone-shaped cigarette tubes, known as cones, can be filled using a packing stick or straw because of their shape. Cone smoking is popular because as the cigarette burns, it tends to get stronger and stronger. A cone allows more tobacco to be burned at the beginning than the end, allowing for an even flavor.

The United States Tobacco Taxation Bureau defines a cigarette tube as "Cigarette paper made into a hollow cylinder for use in making cigarettes

ategory, which is not surprising seeing the numbers in the table above of waste produced each year. Cigarette filters contain the chemicals filtered from cigarettes and can leach into waterways and water supplies. The toxicity of used cigarette filters depends on the specific tobacco blend and additives used by the cigarette companies. After a cigarette is smoked, the filter retains some of the chemicals, and some of which are considered carcinogeniWhen studying the environmental impact of cigarette filters, the various chemicals that can be found in cigarette filters are not studied individually, due to its complexity. Researchers instead focus on the whole cigarette filter and its LD50. LD50 is defined as the lethal dose that kills 50% of a sample population. This allows for a simpler study of the toxicity of cigarettes filters. One recent study has looked at the toxicity of smoked cigarette filters (smoked filter + tobacco), smoked cigarette filters (no tobacco), and unsmoked cigarette filters (no tobacco). The results of the study showed that for the LD50of both marine topsmelt (Atherinops affinis) and freshwater fathead minnow (Pimephales promelas), smoked cigarette filters + tobacco are more toxic than smoked cigarette filters, but both are severely more toxic than unsmoked cigarette filters.

LD50 of cigarette filters to marine life (cigarette per liter)

Other health concerns

Toxic chemicals are not the only human health concern to take into considerations; the others are cellulose acetate and carbon particles that are breathed in while smoking. These particles are suspected of causing lung damage. The next health concern is that of plants. Under certain growing conditions, plants on average grow taller and have longer roots than those exposed to cigarette filters in the soil. A connection exists between cigarette filters introduced to soil and the depletion of some soil nutrients over a period time. Another health concern to the environment is not only the toxic carcinogens that are harmful to the wildlife, but also the filters themselves pose an ingestion risk to wildlife that may presume filter litter as food. The last major health concern to make note of for marine life is the toxicity that deep marine topsmelt and fathead minnow pose to their predators. This could lead to toxin build-up (bioaccumulation) in the food chain and have long reaching negative effects. Smoldering cigarette filters have also been blamed for triggering fires from residential area o major wildfires and bushfires which has caused major property damage and also death well as disruption to services by triggering alarms and warning systems.

Degradation

Once in the environment, cellulose acetate can go through biodegradation and photodegradation. Several factors go into determining the rate of both degradation process. This variance in rate and resistance to biodegradation in many conditions is a factor in litterin and environmental damage.

Biodegradation

Chemical hydrolysis of cellulose acetate
The first step in the biodegradation of cellulose acetate is the deactylation of the acetate from the polymer chain (which is the opposite of acetylation). An acetate is a negative ion with the chemical formula of C2H3O2−. Deacetylation can be performed by either chemical hydrolysis or acetylesterase. Chemical hydrolysis is the cleavage of a chemical bond by addition of water. In the reaction, water (H2O) reacts with the acetic ester functional group attached the cellulose polymer chain and forms an alcohol and acetate. The alcohol is simply the cellulose polymer chain with the acetate replaced with an alcohol group. The second reaction is exactly the same as chemical hydrolysis with the exception of the use of an acetylesterase enzyme. The enzyme, found in most plants, catalyzes the chemical reaction shown below.

acetic ester + H2O ⇌ alcohol + acetate

In the case of the enzymatic reaction, the two substrates (reactants) are again acetic ester and H2O, the two products of the reaction are alcohol and acetate. This reaction is exactly the same as the chemical hydrolysis. Both of these products are perfectly fine in the environment. Once the acetate group is removed from the cellulose chain, the polymer can be readily degraded by cellulase, which is another enzyme found in fungi, bacteria, and protozoans. Cellulases break down the cellulose molecule into monosaccharides ("simple sugars") such as beta-glucose, or shorter polysaccharides and oligosaccharides.

The chemical structure change of cellulose into glucose
These simple sugars are not harmful to the environment and are in fact are a useful product for many plants and animals. The breakdown of cellulose is of interest in the field of biofuel.[103] Due to the conditions that affect the process, large variation in the degradation time of cellulose acetate occurs.

Factors in biodegradation

The duration of the biodegradation process is cited as taking as little as one month to as long as 15 years or more, depending on the environmental conditions. The major factor that affects the biodegradation duration is the availability of acetylesterase and cellulase enzymes. Without these enzymes, biodegradation only occurs through chemical hydrolysis and stops there. Temperature is another major factor, if the organisms that contain the enzymes are too cold to grow, then biodegradation is severely hindered. Availability of oxygen in the environment also affects the degradation. Cellulose acetate is degraded within 2–3 weeks under aerobic assay systems of in vitro enrichment cultivation techniques and an activated sludge wastewater treatment system. It is degraded within 14 weeks under anaerobic conditions of incubation with special cultures of fungi. Ideal conditions were used for the degradation (i.e. right temperature, and available organisms to provide the enzymes). Thus, filters last longer in places with low oxygen concentration (ex. swamps and bogs). Overall, the biodegraditon process of cellulose acetate is not an instantaneous process.

Photodegradation

The other process of degradation is photodegradation, which is when a molecular bond is broken by the absorption of photon radiation (i.e. light). Due to cellulose acetate carbonyl groups, the molecule naturally absorbs light at 260 nm,but it contains some impurities which can absorb light. These impurities are known to absorb light in the far UV light region (< 280 nm). The atmosphere filters radiation from the sun and allows radiation of > 300 nm only to reach the surface. Thus, the primary photodegradation of cellulose acetate is considered insignificant to the total degradation process, since cellulose acetate and its impurities absorb light at shorter wavelengths. Research is focused on the secondary mechanisms of photodegradation of cellulose acetate to help make up for some of the limitations of biodegradation. The secondary mechanisms would be the addition of a compound to the filters that would be able to absorb natural light and use it to start the degradation process. The main two areas of research are in photocatalytic oxidation and photosensitized degradation Photocatalytic oxidation uses a species that absorbs radiation and creates hydroxyl radicals that react with the filters and start the breakdown. Photosensitized degradation, though, uses a species that absorbs radiation and transfers the energy to the cellulose acetate to start the degradation process. Both processes use other species that absorbed light > 300 nm to start the degradation of cellulose acetate.[citation needed]

Solution and remediation projects

A cigarette disposal canister, encouraging the public to dispose of their cigarettes properly
Several options are available to help reduce the environmental impact of cigarette butts. Proper disposal into receptacles leads to decreased numbers found in the environment and their effect on the environment. Another method is making fines and penalties for littering filters; many governments have sanctioned stiff penalties for littering of cigarette filters; for example, Washington imposes a penalty of $1,025 for littering cigarette filters. Another option is developing better biodegradable filters; much of this work relies heavily on the research in the secondary mechanism for photodegradation as stated above, but a new research group has developed an acid tablet that goes inside the filters, and once wet enough, releases acid that speeds up the degradation to around two weeks. The research is still only in test phase and the hope is soon it will go into production. The next option is using cigarette packs with a compartment in which to discard cigarette butts, implementing monetary deposits on filters, increasing the availability of butt receptacles, and expanding public education. It may even be possible to ban the sale of filtered cigarettes altogether on the basis of their adverse environmental impact. Recent research has been put into finding ways to use the filter waste to develop a desired product. One research group in South Korea has developed a simple one-step process that converts the cellulose acetate in discarded cigarette filters into a high-performing material that could be integrated into computers, handheld devices, electrical vehicles, and wind turbines to store energy. These materials have demonstrated superior performance as compared to commercially available carbon, grapheme, and carbon nanotubes. The product is showing high promise as a green alternative for the waste problem.

Consumption

A Woolworths supermarket cigarette counter in New South Wales, Australia: In January 2011, Australia prohibited the display of cigarettes in retail outlets countrywide.
As of 2002, about 5.5 trillion cigarettes were produced globally, and were smoked by over 1.1 billion people, or greater than one-seventh of the world population. While smoking rates have leveled off or declined in developed nations, they continue to rise in developing parts of the world. Smoking rates in the United States have dropped by half from 1965 to 2006, falling from 42% to 20.8% of adults. In the developing world, tobacco consumption is rising by 3.4% per year. Smoking rates in Australia have dropped 4.9% in the year that ended in March 2014. Consumption of cigarettes and tobacco dropped 7.6% in the first quarter in Australia, and 0.1% of the nation’s gross domestic product was clipped from the cut in household consumption of cigarettes. Australia is cutting their overall smoking consumption faster than most of the developed world, in part due to landmark legislation passed banning logos on cigarette cartons, and instead replacing labels with graphic images of sick or dying cigarette smokers and dire health warnings in front of the images. This legislation, passed in 2011, is called Australia’s Plain Packaging Act, and was fought in the country’s High Court by manufacturers of tobacco products. The legislation has significantly reduced consumption in Australia, and could serve as precedent for many other governments currently expanding restrictive legislation on cigarette and tobacco use. An independent review made by one of Britain’s most prominent doctors, Cyril Chantler, may be one of the first steps for Britain to follow Australia in cutting its overall household consumption. In his report, he notes that “standardized packaging would serve to reduce the rate of children taking up smoking.” Ireland’s health minister, James Reilly, has said the government has passed a draft bill in 2014 on plain packaging. In New Zealand, a bill has been presented to parliament in which the government’s associate health minister said “takes away the last means of promoting tobacco as a desirable product.”

Smoking prevalence by sex (2000)

Percent smoking
Region Men Women
Africa 29% 4%
United States 35% 22%
Eastern Mediterranean 35% 4%
Europe 46% 26%
Southeast Asia 44% 4%
Western Pacific 60% 8%
Source: World Health Organization estimates, 2000

Leading consumers of cigarettes (1998
Country Population
(millions) Cigarettes consumed
(billions) Cigarettes consumed
(per capita)
China 1,248 1,643 1,320
USA 270 451 1,670
Japan 126 328 2,600
Russia 146 258 1,760
Indonesia 200 215 1,070

Smoking prevalence in the U.S. (2006)

Rank State % Rank State % Rank State % Rank State %
1 KY 28.6 14 SC 22.3 27 KS 20.0 40 AZ 18.1
2 WV 25.7 15 NV 22.2 28 GA 20.0 41 VT 18.0
3 OK 25.7 16 NC 22.1 29 ND 19.6 42 DC 17.9
4 MS 25.1 17 DE 21.7 30 VA 19.3 43 CO 17.9
5 AK 24.2 18 WY 21.6 31 RI 19.3 44 MA 17.8
6 IN 24.1 19 PA 21.5 32 MT 19.0 45 MD 17.8
7 AR 23.7 20 IA 21.5 33 NH 18.7 46 HI 17.5
8 LA 23.4 21 FL 21.0 34 NE 18.6 47 WA 17.1
9 MO 23.3 22 ME 20.9 35 OR 18.5 48 CT 17.0
10 AL 23.3 23 WI 20.8 36 NY 18.3 49 ID 16.8
11 TN 22.6 24 IL 20.5 37 MN 18.3 50 CA 14.9
12 OH 22.5 25 SD 20.4 38 TX 18.1 51 UT 9.8
13 MI 22.4 26 NM 20.2 39 NJ 18.1

Health effects

Artistas brand cigarette package of Mexico from the Museo del Objeto del Objeto collection
Nicotine, the primary psychoactive chemical in cigarettes, is highly addictive. The resulting use of tobacco is the single greatest cause of preventable death globally. Smoking leads most commonly to diseases affecting the heart, liver, and lungs, being a major risk factor for heart attacks, strokes, chronic obstructive pulmonary disease (COPD) (including emphysema and chronic bronchitis), and cancer (particularly lung cancer, cancers of the larynx and mouth, and pancreatic cancer). It also causes peripheral vascular disease and hypertension. On average, each cigarette smoked is estimated to shorten life by 11 minutes. Starting smoking earlier in life and smoking cigarettes higher in tar increases the risk of these diseases.
The World Health Organization estimates that tobacco caused 5.4 million deaths in 2004 and 100 million deaths over the course of the 20th century. Cigarettes produce an aerosol containing over 4,000 chemical compounds, including nicotine, carbon monoxide, acrolein, and oxidant substances.Over 50 of these are carcinogens.

The most important chemical compounds causing cancer are those that produce DNA damage since such damage appears to be the primary underlying cause of cancer.Cunningham et al.combined the microgram weight of the compound in the smoke of one cigarette with the known genotoxic effect per microgram to identify the most carcinogenic compounds in cigarette smoke. The seven most important carcinogens in tobacco smoke are shown in the table, along with DNA alterations they cause.

The most genotoxic cancer causing chemicals in cigarette smoke

Compound Micrograms per cigarette Effect on DNA.
Acrolein 122.4 Reacts with deoxyguanine and forms DNA crosslinks, DNA-protein crosslinks and DNA adducts
Formaldehyde 60.5 DNA-protein crosslinks causing chromosome deletions and re-arrangements
Acrylonitrile 29.3 Oxidative stress causing increased 8-oxo-2'-deoxyguanosine
1,3-butadiene 105.0 Global loss of DNA methylation (an epigenetic effect) as well as DNA adducts
Acetaldehyde 1448.0 Reacts with deoxyguanine to form DNA adducts
Ethylene oxide 7.0 Hydroxyethyl DNA adducts with adenine and guanine
Isoprene 952.0 Single and double strand breaks in DNA
"Ulcerative colitis is a condition of nonsmokers in which nicotine is of therapeutic benefit." A recent review of the available scientific literature concluded that the apparent decrease in Alzheimer disease risk may be simply because smokers tend to die before reaching the age at which it normally occurs. "Differential mortality is always likely to be a problem where there is a need to investigate the effects of smoking in a disorder with very low incidence rates before age 75 years, which is the case of Alzheimer's disease", it stated, noting that smokers are only half as likely as nonsmokers to survive to the age of 80.

Second-hand smoke

Second-hand smoke is a mixture of smoke from the burning end of a cigarette, and the smoke exhaled from the lungs of smokers. It is involuntarily inhaled, lingers in the air hours after cigarettes have been extinguished, and can cause a wide range of adverse health effects, including cancer, respiratory infections, and asthma. Nonsmokers who are exposed to second-hand smoke at home or work increase their heart disease risk by 25–30% and their lung cancer risk by 20–30%. Second-hand smoke has been estimated to cause 38,000 deaths per year, of which 3,400 are deaths from lung cancer in nonsmokers. Sudden infant death syndrome, ear infections, respiratory infections, and asthma attacks can occur in children who are exposed to second-hand smoke.Scientific evidence shows no level of exposure to second-hand smoke is safe.

Smoking cessation

Smoking cessation can be achieved with or without assistance from healthcare professionals or the use of medications.Methods that have been found to be effective include interventions directed at or through health care providers and health care systems; medications including nicotine replacement therapy (NRT) and varenicline; individual and group counselling; and web-based or stand-alone computer programs. Although stopping smoking can cause short-term side effects such as reversible weight gain, smoking cessation services and activities are cost-effective because of the positive health benefits.

At the University of Buffalo, researchers found out that fruit and vegetable consumption can help a smoker cut down or even quit smoking

A growing number of countries have more ex-smokers than smokers.[149]
Early "failure" is a normal part of trying to stop, and more than one attempt at stopping smoking prior to longer-term success is common.
NRT, other prescribed pharmaceuticals, and professional counselling or support also help many smokers.
However, up to three-quarters of ex-smokers report having quit without assistance ("cold turkey" or cut down then quit), and cessation without professional support or medication may be the most common method used by ex-smokers.
Tobacco contains nicotine. Smoking cigarettes can lead to nicotine addiction.2300–2301 The addiction begins when nicotine acts on nicotinic acetylcholine receptors to release neurotransmitters such as dopamine, glutamate, and gamma-aminobutyric acid.2296 Cessation of smoking leads to symptoms of nicotine withdrawal such as anxiety and irritability.2298 Professional smoking cessation support methods generally endeavour to address both nicotine addiction and nicotine withdrawal symptoms.

The number of nicotinic receptors in the brain returns to the level of a nonsmoker between 6 and 12 weeks after quitting.

Replacement

Various types of electronic cigarettes.

Electronic cigarettes are battery-powered vaporizers that simulate the feeling of smoking, but without tobacco. Their use is commonly called "vaping".The user activates the e-cigarette by taking a puff or pressing a button.Some look like traditional cigarettes, but they come in many variations.Most are reusable but there are also disposable versions called first generation cigalikes. There are also second, third, and fourth generation devices. Instead of cigarette smoke, the user inhales an aerosol, commonly called vapor. E-cigarettes typically have a heating element that atomizes a liquid solution known as e-liquid. E-liquids usually contain propylene glycol, glycerin, nicotine, and flavorings.

The benefits and the health risks of e-cigarettes are uncertain. There is tentative evidence that they can help people quit smoking, but they have not been proven better than regulated medication. Their usefulness in tobacco harm reduction is unclear, but they could form part of future strategies to decrease tobacco related death and disease. Their safety risk to users is similar to that of smokeless tobacco. Regulated nicotine replacement products are safer than e-cigarettes, but e-cigarettes are probably safer than smoking.

Non-smokers who use e-cigarettes risk nicotine addiction. The e-liquid has a low level of toxicity, and contamination with various chemicals has been identified in the product. E-cigarette vapor contains fewer toxic substances,and lower concentrations of potential toxic substances than cigarette smoke. Metal parts of e-cigarettes in contact with the e-liquid can contaminate it with metals. Normal usage of e-cigarettes generates very low levels of formaldehyde. A 2015 review found that later-generation e-cigarettes set at higher power may generate equal or higher levels of formaldehyde compared to smoking. A 2015 review found that these levels were the result of overheating under test conditions that bear little resemblance to common usage. No serious adverse effects from e-cigarettes have been reported in trials. Less serious adverse effects include throat and mouth inflammation, vomiting, nausea, and cough. The long-term effects of e-cigarette use are unknown.

Insufficient data are available to determine the impact on public health from e-cigarettes. The potential harm to bystanders from e-cigarettes is unknown. No long-term data are available. A white paper published in 2014 by the American Industrial Hygiene Association concluded e-cigarettes emit airborne contaminants that may be inhaled by the user and those nearby. Due to this possible risk, they urged restriction of their use indoors, similar to smoking bans, until research has shown the aerosol does not significantly harm others in the area A 2014 review indicated that the levels of inhaled contaminants from the e-cigarette vapor are not of significant health concern for human exposures by the standards used in workplaces to ensure safety. The British Medical Association reported in 2013 that "concerns [exist] that the use of e-cigarettes could threaten the norm of not smoking in public places and workplaces."The use of e-cigarettes in a smoke-free area could expose nonusers to toxins. The effect on bystanders would likely be much less harmful than traditional cigarettes.