Review of related literature and studies




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CHAPTER II

REVIEW OF RELATED LITERATURE AND STUDIES


Petrolatum (also known as petroleum jelly or paraffin jelly) can be defined as a semisolid mixture of hydrocarbons obtained through the dewaxing of heavy mineral oils. Petrolatum is a complex mixture of hydrocarbons derived from the distillation of petroleum. Hydrocarbons are compounds that contain only carbon and hydrogen. The hydrocarbons that make up petrolatum belong to the methane (saturated or alkane) family of hydrocarbons with the general formula CnH2N+2. Petrolatum is also a product of the fractional distillation of crude oil.  (Gale T., 2008)

Petroleum jellies ranges in color from white to yellowish to amber. It is practically odorless and tasteless, oily liquid. It melts over a wide range, from about 38°C to about 55°C (100°F to 131°F). It is insoluble in water but soluble in dichloromethane, chloroform, benzene, diethyl ether, carbon disulfide and oil of turpentine (“Petroleum Jelly”; Wikipedia, 2011).

Petrolatum is an example of a colloid; a hydrocolloid. A hydrocolloid is defined as a colloid system wherein the colloid particles are dispersed in water. A hydrocolloid has colloid particles spread throughout water (H2O). Hydrocolloids can be either reversible (when the physical condition of the hydrocolloid is changed by temperature) or irreversible (when the physical condition of the hydrocolloid is not changed by temperature). Other examples of hydrocolloids include xanthan gum, gum Arabic, guar gum, locust bean gum, cellulose derivatives as carboxymethyl cellulose, alginate and starch (“Colloid”; Wikipedia, 2011). They can be simply defined as a substance that forms a gel in contact with water.

Hydrocolloids are a special type of colloids. Colloids are a type of mixture A colloid is composed of two phases namely, dispersion medium and dispersed phase. Colloids are the mixtures in which dispersion phase is evenly distributed in the dispersion medium. Colloidal system can be solid, liquid or gaseous. Colloidal systems and their study were introduced by a Scottish scientist Thomas Graham (TutorVista.com, 2010).

Colloids have the appearance of solutions. One property of colloid systems that distinguishes them from true solutions is that colloidal particles scatter light. If a beam of light, such as that from a flashlight, passes through a colloid, the light is reflected and scattered by the colloidal particles and the path of the light can therefore be observed (The Columbia Electronic Encyclopedia 6th ed., 2007).

When a beam of light passes through a true solution, there is little scattering of the light that the path of the light cannot be seen and the small amount of scattered light cannot be detected except by very sensitive instruments. The scattering of light by colloids, known as the Tyndall effect, was first explained by the British physicist John Tyndall in 1869. Some colloids are translucent because of the Tyndall effect, which is the scattering of light by particles in the colloid. Other colloids may be opaque or have a slight color (The Columbia Electronic Encyclopedia 6th ed., 2007).

When an ultra microscope is used to examine a colloid, the colloidal particles appear as tiny points of light in constant motion. This motion, called Brownian movement, helps keep the particles in suspension. 

Absorption is another characteristic of colloids, since the finely divided colloidal particles have a large surface area exposed. The presence of colloidal particles has little effect on the colligative properties of a solution. (The Columbia Electronic Encyclopedia 6th ed., 2007)

Petrolatum occurs in a semi-solid or liquid form. The semi-solid form is also called petroleum jelly or mineral jelly and is commercially available under a number of trade names, including Kremoline, Pureline, Sherolatum, and Vaseline™. The liquid form is also known as liquid paraffin, mineral oil, or white mineral oil; such products are sold commercially under trade names such as Alboline, Drakeol, Frigol, Kremol, and Paroleine (Chemical Compounds, 2008).

The beneficial properties of petroleum jellies for skin care and treatment have been extensively reported (Morrison, 1996). Petrolatum has a wide variety of uses, ranging from personal care and medical applications to industrial uses. The solid form, such as Vaseline™ is used as a topical ointment for the treatment of dry, cracked skin and to reduce the risk of infection.  (Gale T., 2008). However, the use of petrolatum can cause some adverse effects. The prolonged use of petroleum can block off the skin’s pores resulting in a thick layer of jelly that covers the skin and also lead to the formation of another layer that mostly comprises secreted toxins, and this second layer leads to the complications like acne, skin irritation, dryness, and other diseases. It can also cause diarrhea, shortness of breath, abdominal pains, and irritation in the eyes, skin, and nose. Petrolatum is also noted as a possible cancer risk, breast cancer to be specific (“Petroleum Jelly Possible Cancer Risk”; Green and Chic, 2008)

Air is a combination of many gases, each one having its own physical properties, in which varying amounts of tiny solid and liquid particles are suspended. Air is made up of 78.084% Nitrogen, 20.946% Oxygen, 0.934% Argon, 0.038% Carbon Dioxide, and trace gases like Neon (0.00182%), Helium (0.000524%), Methane (0.00015%), Krypton (0.000114%), and Hydrogen (0.00005%). Water vapor, ozone, and aerosols (tiny suspended solid and liquid particles in the air) are variable components of air (Tarbuck & Lutgens, 2009).

Air quality, as Wikipedia (2011) defines, is the “measure of the condition of air relative to the requirements of one or more biotic species and/or to any human need or purpose” (“Air Quality”; Wikipedia, 2011). The measure of air quality means the measurement of the pollutants in the air (“Air Quality”; Dictionary.com, 2011). Bad air quality means there are a lot of air pollutants in the air which include fine particles.

Dr. Sarath Guttikunda said in a blog published in 2007 that Air Quality Index (AQI) is an ‘index’ determined by calculating the degree of pollution in the city or at the monitoring point and includes five main pollutants - particulate matter, ground-level ozone, sulfur dioxide, carbon monoxide and nitrogen dioxide. Each of these pollutants have an air quality standard which is used to calculate the overall AQI for the city. Simultaneously, one can also establish the limiting pollutant(s), resulting in the estimating AQI. Government agencies use the AQI to characterize the quality of the air at a given location.

In numbers, AQI is represented between 0 to 500 with 0 representing good air and 500 representing hazardous air. For better understanding and presentation, the AQI is broken down into six categories, each color coded with the number scale.

Good (green) is for numbers 0 through 50 and means satisfactory air quality. Moderate (yellow) is 51-100 and is for acceptable air quality. Unhealthy for Sensitive Groups (tan) is 101-150 and means sensitive individuals with sensitive skin may be affected. Unhealthy (red) is 151-200 and almost everyone may experience problems. Very unhealthy (pink) 210-300 is a health alert, where everyone may have health problems. Hazardous (purple) over 300 numbers may contribute to emergency health problems and will affect most people.

There are units used to measure air quality. Parts per million (ppm), parts per billion (ppb), micrograms per cubic meter (/m3), and soiling index (also known as coefficient of haze, COH) are common means of reporting air quality measurement (Environment Software and Services Austria, 2011).

When harmful substances are introduced to the air, the AQI increases (worsens), meaning that the air is polluted. Air pollution occurs when the air contains gases, dust, fumes or odor in excess and harmful amounts. These amounts could be harmful to the health and could cause damage to plants and materials. According to EPA Victoria in an article published in 2006, air pollution has now been one of theg major problems faced by every country worldwide. Air pollution contains air pollutants that mainly occur as a result of gaseous discharges from industry and motor vehicles. There are also natural sources such as wind-blown dust and smoke from fires. Some forms of air pollution create global problems, such as upper atmosphere ozone depletion and global warming. These problems are very complex, and require international cooperative efforts to find solutions (EPA Victoria, 2006).

In article published in 2010, Sevier states that the polluted air contains five main pollutants that can cause health effects. They are carbon monoxide (CO), oxides of nitrogen (NOx), VOCs (Volatile Organic Compounds) and ozone, sulphur dioxide, and fine particles.

Carbon monoxide is a poisonous gas produced mainly by petrol engines; it damages respiratory and circulatory body functions and reduces oxygen supply to major organs including the heart. Oxides of nitrogen are found in vehicle and smokestack exhaust; it compromise lung functions and can cause respiratory and viral illness, notably in children (Sevier, 2010).

VOCs are emitted as gases from certain solids or liquids. It includes chemicals that may have adverse health effects, either short or long term. VOC concentrations are consistently higher indoors than outdoors, and are emitted by several products which include paints and lacquers, paint strippers, pesticides, building materials and furnishings, office equipment such as copiers and printers, correction fluids and carbonless copy paper, graphics and craft materials including glues and adhesive permanent markers (United States Environmental Protection Agency, 2011). VOCs react with sunlight and nitrous oxide and form ground level ozone, which is capable of travelling thousands of miles; although in the stratosphere, ozone provides vital protection against the sun's ultraviolet radiation, at ground level it can exacerbate health conditions such as asthma and lung disease. (Sevier, 2010)

Sulphur dioxide is created through the combustion of fossil fuels that contain sulphur compounds; it can contribute to various lung conditions even at moderate levels of concentration. Fine particles include dusts, sulphates and nitrates from road traffic and other sources. These fine particles can be carcinogenic and are able to pass through the lungs into the bloodstream, causing inflammation as well as more serious conditions (Sevier, 2010).

This study focuses more about the particulates. Particles of concern include both very small, "fine" particles (that can only be seen through an electron microscope) and somewhat larger "coarse" dust particles. Fine particles have been more clearly linked to the most serious health problems.

According to AirNow in August 2003, particles in the air are a mixture of solids and liquid droplets that vary in size and are often referred to as "particulate matter." Some particles - those less than 10 micrometers in diameter - pose the greatest health concern because they can pass through the nose and throat and get deep into the lungs.

Ten micrometers in diameter is just a fraction of the diameter of a single human hair. Particles larger than 10 micrometers do not usually reach the lungs, but they can irritate the eyes, nose and throat (AirNow, August 2003).

Very small particles with diameters less than 2.5 micrometers are called "fine particles." They are produced any time fuels such as coal, oil, diesel or wood are burned. Fine particles come from fuel used in everything from power plants to wood stoves and motor vehicles (e.g., cars, trucks, buses and marine engines). These particles are even produced by construction equipment, agricultural burning and forest fires. "Coarse" dust particles range in size from 2.5 to 10 micrometers in diameter. Particles of this size are produced during crushing or grinding and from vehicles traveling on paved or unpaved roads (AirNow, August 2003).

According to the Ministry for the Environment on an article published in 2008, Total Suspended Particulate (TSP) comes from sources like dusty roads, soil tiling, quarries and fuel combustion. Particles with a diameter less than 10 microns (PM10) and Particles with a diameter less than 2.5 microns (PM2.5) come from sources such as burning coal, oil, wood and light fuel oil in domestic fires, transportation and industrial processes. Natural sources of particles include sea salt, dust, pollens and volcanic activity. PM2.5 is also formed through chemical reactions in the atmosphere. (Ministry for the Environment, January 2008)

AirNow also mentioned in an article published in August 2003 that particles can aggravate heart diseases such as congestive heart failure and coronary artery disease. If a person has a heart disease, particles may cause him to experience chest pain, palpitations, shortness of breath and fatigue. Particles have also been associated with cardiac arrhythmias and heart attacks. Particles can also aggravate lung diseases such as asthma and bronchitis, causing increased medication use and doctor visits. If a person has lung disease, and the person is exposed to particles, the person may not be able to breathe as deeply or vigorously as normal. The person may have respiratory symptoms including coughing, phlegm, chest discomfort, wheezing and shortness of breath. The person also may experience these symptoms even if the person is healthy, although he is unlikely to experience more serious effects. Particles can also increase the susceptibility to the body’s respiratory infections.

Particles in the air causes so much damage. People’s health need to be protected from those air particles but first one must know if there are any in the area. One device called TSI P-Trak Ultrafine Particle Counter, records particulates in the air. It is a particulate monitor that is used to measure specific sizes of material suspended in air.  It uses the same fundamental technology behind TSI's condensation particle counters (CPCs), well-proven instruments that have been used in research and industrial applications around the world for many years. In fact, CPCs have been used for decades to track and record particle sources. The P-Trak UPC comes with everything you need to start solving tough IAQ (indoor air quality problems). The device is also battery-operated (Pine Environmental Services, Inc., 2009). This device costs much and it is to no avail in our area. But an alternative method for determining the quality of air without the use of such devices and without spending too much money, can be done. One way to determine the quality of air is by using petrolatum as a trap for particulates found the air, according to an article in eHOW published in 2011. The chances are great for the determination of the quality of air because of the translucency of the petrolatum; the particulates stuck in the petrolatum can be easily seen.

Fine particles in the air reduce visibility because they scatter or absorb light. This is usually associated with small particles or certain gases in the atmosphere and can occur at night or during the day.






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