Lunes, Enero 20, 2014

A new level of risk from smoking residue: Third Hand Smoke

It is common knowledge that the smoke that comes from cigarettes and other tobacco products takes on two forms. The first of which is the smoke that goes inside the smoker’s body, inhaled directly. The second form is the smoke that the smoker exhales. However, a new form of cigarette smoke has been discovered and it is found to produce a new kind of health hazard. Coined “Third Hand Smoke”, this finding contributes to the known risks associated with cigarette smoking.

            The smoke directly inhaled by the smoker from the cigarette is known as ‘first hand smoke’ while the smoke exhaled afterwards is called ‘second hand smoke’. Second hand smoke can be inhaled by other people that are within the vicinity of the smoker. Numerous studies have been committed to studying the health risks of smoking on a first hand basis. The perils of second hand smoke has also received considerable attention for it affects a wider range of people. [1] However, it has been discovered by researchers and doctors from the Dana – Farber/Harvard Cancer Center in Boston, that second hand smoke generates another kind of hazard that pose threats to health, in the form of nicotine residue settling on furniture and other surfaces. [2][3][4] Doctors from the Mass General Hospital for Children, also located in Boston, called these residues Third hand smoke. [3]

            Third hand smoke is defined as the leftover nicotine from tobacco products that has accumulated on surfaces, clothes, body parts, etc. long after the second hand smoke has cleared.[1][3][4] From a more technical and inclusive standpoint, researchers from ASH Scotland developed a three ‘r’ definition of third hand smoke. According to a fact sheet released by the organization, Third hand smoke:

“Describes the residual tobacco smoke pollutants which remain on the surfaces and in dust after tobacco has been smoked, are re-emitted back into the gas phase, or react with oxidants and other compounds in the environment to yield secondary pollutants”. – ASH Scotland [2]

The residue, in itself, is already dangerous because it consists of heavy metal, and radioactive materials. It is said to contain, among others, hydrogen cyanide used in weapons, butane or lighter fluid, lead, arsenic, carbon monoxide, and the highly radioactive Polonium 210, that was formerly used as weapon in Russia. [3][4] However, the more hazardous effect of third hand smoke emanates from the reactive nature of the residues, which can form carcinogens if combined with the right chemicals, one of which is nitrous acid which comes from gas appliances such as stoves, and ovens. [1][2] Once nicotine residues, and nitrous acid combine, ‘carcinogenic tobacco-specific nitrosamines’ (TSNAs) are formed, which is one of the most potent carcinogenic elements known. [1][2] Given that nicotine rapidly adheres to surfaces quickly and is difficult to remove, frequent smoking indoors can quicken the pace of carcinogenic TSNA production. [2]

Third-hand smoke was found to be particularly threatening for infants and toddlers. Infants and toddlers, especially crawlers, have comparably higher contact to surfaces than adults. Children of this age group are also known to frequently insert objects in their mouth. [2][4] In addition, infants have also been found to inhale 40% more household dust than adults. [2] TSNAs can be acquired through inhalation, ingestion, or even just plain contact with skin (dermal exposure). [1][2][3] From this, it can be said that surfaces, objects, even small particles such as dust, that have been exposed to TSNAs or nicotine residues would have already acquired the carcinogenic or radioactive properties and will be extremely dangerous to come into contact with children. 

Not only are these residues invisible, [3] but they are also accumulative and can persist on for months. [1] Simple washing cannot effectively remove these nicotine residues. Soap that is alkaline will not be able to remove these residues, and particles that have stuck on surfaces with textures similar to carpets are practically irremovable. Increasing ventilation as well has been proven to be incapable of removing third hand smoke though it may aid in clearing away second hand smoke.[2]

But what sets apart the hazards of Third hand smoke from that of first hand smoke and second hand smoke? Aside from it being carcinogenic (especially in TSNA form), radioactive, and poisonous, [1][2][3][4] exposure to the lead content, even on small doses,  was also shown to contribute to lower IQs, especially if the exposure starts from a very young age. According to an article on third hand smoke published on the ‘Scientific American’, “the developing brain is uniquely susceptible to extremely low levels of toxins”. [4] In addition, third hand smoke has also been found to be ‘mutagenic’, or is capable of altering genetic material. Researchers from the Lawrence Berkeley National Laboratory in the US discovered that third hand smoke is capable of changing the structure of DNA, but in a damaging way. In addition, the damage that third hand smoke does on the DNA was also found to get worse over time. Aside from the mutagenic nature of third hand smoke, it was also found to be ‘genotoxic’ which, according to the article, is a “known player in the development of cancer and other disease as a result of smoke”. [5]

            At present, there has not yet been any recorded case of disease that was directly caused by third hand smoke. [4] In addition, there has been little real-life evidence to support its capability to directly cause disease although a definite system of TSNA production from third hand smoke has been traced. [2] Despite these, the discovery of third hand smoke, the longevity of its effects, and the risks associated with it still has major implications towards advocating to ‘kick the smoking habit’.

References:
1.      1. LiveScience (2012, Feb 9). ‘Today news: Third hand smoke a danger to babies, toddlers. Retrieved from http://www.today.com/id/35318118/ns/today-today_health/t/third-hand-smoke-danger-babies-toddlers/
2.      2. ASH Scotland. Action on Smoking and Health Scotland, (2011). ASH Scotland: Third-hand smoke. Retrieved from ASH Scotland website: http://www.ashscotland.org.uk/media/3942/Thirdhandsmoke.pdf
3.      3. Rabin, RC (2009, Jan 3). ‘The New York Times: A new cigarette hazard: third-hand smoke’. Retrieved from http://wkeithward.com/Articles/A%20New%20Cigarette%20Hazard%20-%20Third-Hand%20Smoke.pdf
4.      4. Ballantyne, C (2009, Jan 6). ‘Scientific American: What is third-hand smoke? Is it hazardous?’. Retrieved from http://www.scientificamerican.com/article.cfm?id=what-is-third-hand-smoke
5.      5. No author (2013, June 24). ‘Huffington Post: Thirdhand smoke spurs DNA damage, study finds’. Retrieved from http://www.huffingtonpost.com/2013/06/24/thirdhand-smoke-dna-damage-cells_n_3474797.html


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