SMOKING- VALEOLOGICALLY DANGEROUS TO HEALTH (10): Cont.: INGREDIENTS IN TOBACCO

[Abbas Bubakar El-ta'alu]

Formaldehyde: Formaldehyde is classified as a human carcinogen by the International Agency for Research on Cancer, and as a probable human carcinogen, by the U.S Environmental Protection Agency (EPA) [American Journal of Public Health]. Formaldehyde in sidestream smoke is evident in concentrations of up to three orders of magnitude above occupational limits, which readily accounts for eye and nasal irritation. 'Low - tar' cigarettes appear at least as irritating as other cigarettes. More than half of the irritation is associated with the particulate phase of the smoke, permitting deposition throughout the entire respiratory tract.
   Formaldehyde is a colourless, flammable, strong-smelling gas. It is an important industrial chemical used in the manufacture of building materials and in the production of many household products. It is used in pressed wood products such as particle board, plywood, fibre board, glues and adhesives, permanent press fabrics, paper product coatings, some insulation materials, etc. In addition, formaldehyde is commonly used as an industrial fungicide, germicide, disinfectant and as a preservative in mortuaries and medical laboratories

Short-term Health Effects of Formaldehyde Exposure: When formaldehyde is present in the air at levels exceeding 0.1 ppm, some individuals may experience health effects such as watery eyes, burning sensations of the eyes, nose and throat; coughing, wheezing, nausea, skin irritation. Some people are very sensitive to formaldehyde, while others have no reaction to the same level of exposure.


Hydrogen Cyanide: Under the name of Zyklon, B., hydrogen cyanide was used as a genocidal agent during World War II, but smokers do it multiple times with every cigarette they light. Because hydrogen cyanide is present in secondhand smoke (see chapter five), non-smokers are also at risk.
   Hydrogen cyanide at room temperature is a volatile, colourless- to-blue liquid (also called hydro cyanide acid). It rapidly becomes a gas that can lead to death in minutes if breathed. It is used in making fibres, plastics, dyes, pesticides, and other chemicals, and as a fumigant to kill rats. It is also used in electroplating metals and in developing photographic film.
   Breathing small amount of hydrogen cyanide may cause headache, dizziness, weakness, nausea, vomiting. Larger amounts may cause gasping, irregular heartbeats, seizure, fainting, rapid death. Generally, the more serious the exposure, the more severe the symptoms.
   Treatment of hydrogen cyanide poisoning includes breathing in pure oxygen and in the case of serious symptoms, treatment with cyanide antidotes.

Carbon monoxide: Carbon monoxide is a colourless, odourless gas – hence its designation as a silent killer. It is produced as a result of incomplete burning of carbon-containing compounds. Exposure to carbon monoxide gas reduces blood ability to carry oxygen to different tissues of the human body. Carbon monoxide combines with haemoglobin at the same point of the haemoglobin molecule as does oxygen and, therefore, can displace oxygen from the haemoglobin. Furthermore, it binds with about 250 times as much tenacity as oxygen [Guyton & Hall. (2000)].
   Carbon monoxide exerts its pathologic effects through a number of different mechanisms. In susceptible tissues, these may include a combination of impaired oxygen delivery, oxygen utilization, and, possibly oxidant stress injury. The higher affinity binding of carbon monoxide to haemoglobin (200 – 250 times the affinity of oxygen for haemoglobin) results in (1) formation of carboxyhaemoglobin (COHb), (2) displacement of oxygen from haemoglobin and lowered oxygen – carrying capacity, and (3) a leftward shift of the Oxyhaemoglobin Dissociation Curve. There is also evidence [Kevin & Wallace. (2001)] that carbon monoxide binds to other haem-containing proteins, such as myoglobin and certain cytochromes, which play a critical role in meeting cellular energy requirements; it is unclear to what extent binding to proteins other than haemoglobin are clinically relevant. Recent experimental evidence [ Kevin & Wallace. (2001)] suggests that relatively intense carbon monoxide exposure can trigger a cascade of events, including brain lipid peroxidation, that leads to trancient and irreversible neural dysfunction.
   Smoke from cigarette can contain high levels of carbon monoxide, as well as 200 other poisons [Terry Martins. (2003)]. Breathing low levels of the gas can cause fatigue, increased chest pain in people with chronic heart disease.
In otherwise practically healthy individuals, breathing higher levels of carbon monoxide causes flu-like symptoms (with no fever) such as headaches, dizziness, body weakness, sleepiness, nausea, vomiting, confusion, disorientation [CPSC].