The three most important substances that make life possible are water, oxygen and carbon dioxide. The primary structural and functional element in all living things is carbon. All carbon in protein, fat, carbohydrate and other organic molecules in living things is derived from atmospheric carbon dioxide. Without atmospheric carbon dioxide, life as we know it would not be possible.
The carbon cycle is the biogeochemical cycle by which carbon is exchanged between the biosphere, geosphere, hydrosphere and atmosphere of our planet Earth. Carbon is stored in four major reservoirs:
• The atmosphere
• The biosphere (including freshwater systems and ground soil)
• The oceans (including dissolved inorganic carbon)
• The sediments (including fossil fuels)
Carbon is exchanged between these reservoirs via sequences of various chemical reactions and biological processes.
Carbon exists in the Earth’s atmosphere primarily as the gas carbon dioxide. Although it is a very tiny percent of the atmosphere (approximately 0.04%), it plays an essential part in supporting life. In particular, plants absorb carbon dioxide in the presence of sunlight to produce carbohydrate, and release oxygen into the air. This process is known as photosynthesis, and provides plants with the key organic compounds required to support life.
In nature, carbon can then be released naturally back into the cycle in many different ways with the most common being respiration, decay of animal and plant matter, and the release of dissolved carbon dioxide from the oceans by marine life.
Carbon in Today’s World
Disruption of the natural carbon cycle occurs with human intervention and the results of exponential growth in the world’s population. Burning of fossil fuels releases stored carbon, increasing the overall percentage of carbon dioxide in the atmosphere.
Today, the debate continues on whether global warming is myth or fact. However, what is certain is that combustion of fossil fuels through industrial activities, vehicle exhaust fumes, smoking, use of petrochemical products in buildings, etc, produces by-products which affect the quality of the air which humans breathe. These by-products are tiny particles, whose chemical composition, particle shape and size are all factors that determine how they impact human health.
The primary by-product of burning fossil fuels is carbon dioxide. However, this exists naturally in the carbon cycle. Of more significance in impacting human health are the by-products of carbon monoxide, nitrogen oxides, sulphur oxides and hydrocarbons. Suspended particles from these compounds can combine in the atmosphere to form tropospheric ozone, the major constituent of smog.
Carbon monoxide is a deadly toxic gas, undetectable by smell that can harm or kill animals, plants and people. It is produced during incomplete combustion of fossil fuels. Inhalation is poisonous and causes headaches, dizziness, nausea, shortness of breath, light-headedness and, in extreme cases, death . People with heart disease will be susceptible to more stress on the heart. Motor vehicles are the primary source of carbon monoxide.
Impact on Air Quality from the Combustion of Fossil Fuels
Both nitrogen dioxide and nitric oxide are also produced in combustion. Unlike carbon monoxide which cannot be detected, nitrogen oxides are yellowish-brown in colour and are the major contributor to haze in city air, injury to plants and destruction of forests near industrial areas. Oxides of nitrogen are emitted by internal combustion engines, power stations, furnaces, cars and fertilizers. Exposure to oxides of nitrogen may lead to death from pulmonary lesions (due to reduced partial oxygen pressure in the lungs); sudden death from spasms of the lungs and respiratory failure; pulmonary oedema; or inflammatory responses in the bronchiole system.
Sulfur oxides are another common by-product of combustion and released into the environment. Exposure to air contaminated with sulphur dioxide will cause irritation of the eyes, nose, throat and lungs, resulting in choking and coughing. Individuals with asthma are particularly sensitive to sulphur dioxide.
Both nitrogen oxides and sulphur oxides are primarily irritants to human health. The by-products of major concern are the polycyclic aromatic hydrocarbons (PAHs), which have been identified as carcinogenic, mutagenic and teratogenic. Polycyclic aromatic hydrocarbons are chemical compounds that consist of fused aromatic rings, whose resulting structure determines whether they are non-toxic or highly toxic. Polycyclic hydrocarbons are not only caused by combustion of fossil fuels, but are also formed by incomplete combustion of wood, coal, diesel, fat, tobacco or incense.
How Our Homes and Offices Affect Health
Hydrocarbons, and other gaseous pollutants, have been the subject of debate for years. Various studies have examined the effects of various fuels on the environment.
What the majority of the general public is less aware of is the quality of the air in our homes and office. Indeed, people spend more than 90 percent of their time indoors. Every day, they consume 25,000 litre of air a day. Inhaling air of poor quality everyday causes Sick Building Syndrome can lead to stress, respiratory illnesses headache, conjunctivitis, asthma, cancerous diseases, etc has become increasingly popular and debatable issues nowadays.
The Environmental Protection Agency’s Total Exposure Assessment Methodology (TEAM) studies have found levels of about a dozen common organic pollutants to be two to five times higher inside homes and office than outside, causing sick building syndrome to the occupants therein .
Volatile Organic Compounds (VOCs) are chemicals emitted as gases from wide variety of sources. There are literally thousands of different VOCs produced, most of which are potentially harmful to health. Levels of VOC exposure in indoor air vary widely depending upon factors such as the building ventilation rate, outdoor concentrations and the time spent in the effected environment, be it home or office.
The walls of buildings emit VOCs from paints; the doors and floors emit VOCs from varnishes, wood preservatives and other solvents. Aerosol sprays, cleaners, disinfectants, repellents, air fresheners and pesticides all emit varying levels of VOCs. Newspapers, printers, photocopy machines, correction fluids, paper and permanent markers all produce VOCs within the office environment. Even less apparent sources such as dry-cleaned laundry, cosmetics and cooking can all cause adverse health effects from emission of VOCs.
Further key contributors to indoor VOC contamination are new carpets, new furniture, idling motor vehicles parked in attached garages, new paint jobs, chemicals stored in the home, recently applied adhesive as well as new plastic or electronic devices. From the materials which make up the building to the chemicals which are used to keep the home “hygienic”, these are all sources of VOCs .
How VOCs Affect Air Quality
Volatile Organic Compounds are gases that are emitted at room temperature. Under the term “organic”, these compounds all contain carbon. Upon entering the air, they react with oxides of nitrogen (in the presence of sunlight) to form ozone. This photochemical process is difficult to control as it is a very natural reaction which takes place close to ground level.
Ozone in the atmosphere is beneficial to human life as it filters potentially damaging ultraviolet light from reaching the Earth’s surface. However, ozone at ground level is a highly reactive gas which pollutes the air and damages human health, the respiratory systems of animals, and vegetation.
Breathing air with high concentrations of ozone can aggravate symptoms of sufferers with pulmonary diseases and increase rates of asthma attacks. Other acute effects of ozone exposure include eye irritation, nose irritation, throat irritation, headaches, nausea and dizziness. There is also evidence to show that prolonged exposure to ozone can cause permanent lung damage, cancer, kidney damage as well as interference with the functioning of the immune system.
Removing Hazardous Volatile Organic Compounds from the Air
There are many different methods for removing or minimising VOCs from the air. However many factors need to be considered in determining the effectiveness of each of these methods.
Source control can be employed to eliminate products from the home that contain high levels of VOCs. Some sources, like asbestos or chipboards, can be sealed or enclosed. However, not all pollutant resources can be identified and practically eliminated or reduced.
Increasing ventilation, especially in the presence of new products or appliances, can be achieved simply by opening windows or doors. Unfortunately, this often brings in air from outside which contains other contaminants from outdoor fuel combustion, etc. In addition, there are limits on measuring the effectiveness with which the airborne pollutants are removed from indoor air.
Air cleaners or purifiers come in many different forms and variations. Generally air purifiers work by removing pollutant particles from the air via filters, activated carbon, oxidation systems, ionisers or ozone generators. The fact remains that each process may remove different contaminants, limiting the full effectiveness of these systems. These filters can be blocked by ducts or particles which reduces its effectiveness as well. Regular maintenance is required for these devices. In particular, there are consumer concerns over the use of ozone generators, given that ozone on ground level is a highly reactive and damaging gas.
A Revolutionary Breakthrough in Removing VOCs from Our Life
Titanium dioxide (TiO2) is a naturally occurring oxide of titanium, mostly found in the minerals rutile, anatase and brookite. It has been classified as Class 4A inert ingredient which is safe to human health . Pure titanium dioxide is produced from chemical processing to leave a pure, white pigment which is odourless and absorbent.
Titanium dioxide in rutile form has a variety of uses, but by far the most widely used application is as a pigment for providing whiteness and opacity to products such as paints, coatings, plastics, paper, inks, fibres, food, toothpastes and cosmetics.
Titanium dioxide is also a potent photo-catalyst, particularly in the anatase form. Under ultraviolet light, UV- A (fluorescent lamps provide sufficient UV-A for such purpose), it has been found that almost any organic compound can be broken down at its surface, in the presence of water vapour. As a result of the photo-catalytic properties of titanium dioxide, new technologies have been developed to capitalise on environmentally beneficial products, with particular interest on the effectiveness of VOC removal.
In the late 1970s, scientists had already begun to realise to potential of titanium dioxide. When exposed to ultra-violet light of a certain wavelength, in the presence of water vapour, two highly reactive chemical species are formed: hydroxyl radicals [OH] and a superoxide ion [O2-1]. Hydroxyl radicals are very strong oxidisers, capable of breaking down any organic matter into carbon dioxide and water (both of which are then harmless to the environment).
An innovative nano Titanium Dioxide coating has been developed recently for the reaction to produce a revolutionary product useful in air purification, water and wastewater remediation and as an advanced cleaning solution . With one application of its spray-based technology, organic molecules, no matter whether they are the result of grime, oils, VOCs or part of the cellular walls of bacterial microbes, are broken down into carbon dioxide and water. This ultra-fast reaction literally takes place in billionths of a second, in the presence of light, water vapour (present in the air) and titanium dioxide.
In addition, the superoxide anions which are produced in this reaction then bind with nitrogen oxides in the air to reduce the harmful components of smog and acid rain down to harmless nitrogen dioxide.
Superior generation of active oxygen anions is at the core of the smog-reducing power of Nano Titanium Dioxide solutions.
The effectiveness of nano-particle of anatase titanium dioxide has been confirmed in the extensive Photocatalytic Innovative Coverings Applications for De-pollution Assessment (PICADA-Project) .
Conclusion
The Environment Protection Agency of USA has invested heavily into researching the revolutionary product of Nano Anatase Titanium Dioxide is a “Green Technology” and harmless to humans. It has become the only solution for air quality, with the potential to replace air cleaners, purifiers, ioner and ozone generators . Nano Titanium Dioxide stands out from the range as an effective means to reduce Volatile Organic Compounds, ozone at ground level, carbon monoxide, and micro-organisms of all types in the air. The true benefits of Nano Titanium Oxide to human health has yet to be tested and realised in Malaysia.
Written jointly with Emily W
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