Dr. S. S. Verma, Department of Physics, S.L.I.E.T., Longowal, Distt.-Sangrur (Punjab)-148106.
Air pollution
Air is the ocean all around us which we breathe and supplies us with oxygen which is essential for our bodies to live. The atmosphere (outdoor as well as indoor) is a complex dynamic natural gaseous system that is essential to support life on planet Earth. Air pollution is the introduction of all unwanted matter like particulate matter, chemicals (gasous or liquid), or biological materials through human activities into the atmosphere in non-permissible limits (or beyond the sustaining limits of environment itself) that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment. There are several main types of pollution and well-known effects of pollution which are commonly discussed. These include smog, acid rain, the greenhouse effect, and “holes” in the ozone layer. Each of these problems has serious implications for our health and well-being as well as for the whole environment. The exhaust from burning of coal in thermal power plants and fuel in automobiles, homes, and industries are the major sources of pollution in the air.
Pollution outdoor and indoor is both interconnected and plays havoc not only in the outdoor atmosphere but also needs to be considered inside our homes, offices, and schools as we spend about 80-90% of our time inside buildings, and so our exposure to harmful indoor pollutants can be serious. Air pollution can affect our health in many ways with both short-term (include irritation to the eyes, nose and throat, and upper respiratory infections such as bronchitis and pneumonia) and long-term effects (include chronic respiratory disease, lung cancer, heart disease, and even damage to the brain, nerves, liver, or kidneys). Research into the health effects of air pollution is ongoing. Medical conditions arising from air pollution can be very expensive. Healthcare costs, lost productivity in the workplace, and human welfare impacts cost billions of dollars each year. Thus, we all want to breathe a clean air but may not bother a bit to contribute in keeping our atmosphere clean.
Coal based industrial revolution replacing human labor with machines had deeply altered human and environmental history. As with the urbanization of thousands of years before, the industrial revolution changed the way people thought about themselves in relation to nature. Industrialization told many people that they had mastered nature, and were now apart from and above it. While the industrial revolution meant that more goods could be produced for human consumption, it also meant that more pollution would be emitted into the sky and more natural resources would have to be exploited in the production process. Industrialization has resulted in pollution of water, air and soil. Harmful waste has increased astronomically. All of these problems pose significant threats to both the environment and to human life.
Role of electronics
There are a large number of air purifier technologies that are used to address the need for clean indoor air. These are mechanical High Efficiency Particulate Air (HEPA) filters, Electronic, UV, Activated Carbon, ionic breeze, ozone, negative ion, and some other adsorption materials like Zeolite Clay. There are only a few however that are actually effective in treating the air without harming the individual. Some of the air purifier technologies used are proven to be more effective than others and some may be harmful to users. Each type of technology that is used in an air purifier is designed to clean the air of specific particles and odors. The effectiveness and efficiency of each technology is measured in different ways. Choosing the best air purifier with the most efficient technology can be easy with some research and comparison. An electronic air purifier is one which uses electrostatic attraction to trap polluting particles and thereby remove them from the airflow. This is in contrast to mechanical air cleaners, which use filters such as HEPA filters to capture particles.
Electronics based technology was looked as a prospective solution not only for outdoor but also for indoor air purification. The technology used in air purifiers can be diverse and unique. There are many different air purifier companies that use different types of technology and mediums to achieve the goal of clean air. Although there are different filtering systems used in air purifiers, many of the systems are just as efficient and effective. Each system has different qualities and specialties that make them exclusive and individualized. An electronic air purifier is an air purifier that uses an advanced and effective type of technology to absorb contaminants in the air. Electronic air purifier products are used for businesses and residences in order to keep the air indoors safer and healthier for people to breathe. The filtering system used in an electronic air purifier uses a cutting edge design and knowledge of the behavior of contaminants in the air in order to work powerfully.
Electronic air cleaners are able to remove particles, fumes, odors and gases from the air. The technology used in electronic air cleaners makes them one of the most effective and advanced types of air purifiers on the market today. Electronic air purifiers are an efficient and low maintenance type of air purifier. They are easy to care for and deliver the same quality as other filtering systems on the market. With at least 95% efficiency, it’s no wonder that electronic air purifiers are becoming a popular and convenient way to provide clean and healthy air. There are two different types of electronic air purifiers, which use different processes to achieve this same end. The first type is the electrostatic precipitators; the second is the ionizer, also called the ion generator. Both types of electronic air purifiers give an electric charge to the polluting particles. Charged particles, or ions, are by nature attracted to other particles with the opposite charge. The end result is that charged particles will be drawn to and then sticks to each other. Electrostatic precipitators and ionizers differ from each other in how they charge the particles and what happens to the particles after they have been charged.
Electronics in its concept of electrostatic precipitators turned out to be a most effective technique to control air pollution from coal burning thermal power plants. An electrostatic precipitator (ESP), or electrostatic air cleaner is a particulate collection device that removes particles from a flowing gas (such as air) using the force of an induced electrostatic charge. The ESP system works on the principle by passing the gas through an electrically charged screen that gives a charge to the particles, then between two charged plates where the particles are attracted to one surface for collection. Electrostatic precipitators are highly
efficient filtration devices that minimally impede the flow of gases through the device, and can easily remove fine particulate matter such as dust and smoke from the air stream. In contrast to wet scrubbers which apply energy directly to the flowing fluid medium, an ESP applies energy only to the particulate matter being collected and therefore is very efficient in its consumption of energy (in the form of electricity).
Electronic ion generators for air purification differ in that, instead of drawing the particles in and then charging them, they release ions into the surrounding air. These ions attach themselves to airborne particles, thereby charging them. The newly charged particles then become attracted to surfaces such as drapes or walls, or they combine with other particles and fall to the floor. Some electronic air purifiers use a one-stage system to clean the air while some use a two-stage system. The one-stage system in an electronic air purifier charges the particles and sticks them to the collection plates. There is only one step that the air goes through of filtering once it enters the air purifier. In a two-stage system, however, the air enters the air purifier and the particles in the air are
charged using high-voltage wires. The charged particles are then pulled into metal plates that are charged oppositely. Both types of electronic air purifiers are just as effective at removing particles from the air. Both types of electronic air-purifying systems also require very low maintenance. There are no filters to change and the air purifiers tend to stay relatively clean. If there is build up that develops, the collection plates can be wiped down with a damp cloth. All of the build up from particles will be removed by a simple wipe and the collection plates will be good as new and perfectly charged. If the collection plates are kept clean and free from particle build up, they will remain efficient and effective in cleaning the air.
Static electricity is the main source of technology used by electronic air purifiers in order to clean the air. The static electricity that is developed by the machine is used to attach a charge to all particles in the air that is taken in by the air purifier. When the particles possess a charge, this charge is attracted to the opposite type of charge. This opposite charge is placed onto collection plates or other types of medium inside the air purifier. This medium attracts the charged particles and they stick to the charged medium instead of staying in the air. Electronic air purifiers are proven to be more efficient at absorbing particles. The reason electronic air purifiers are more effective at cleaning the air is that when particles are charged as opposed to just being absorbed, they stick easier to the medium. There are more particles removed and there is a better chance of them being absorbed by the filter when they possess the charge given by an electronic air purifier. An electronic air purifier is measured to have 95% efficiency or more. The size of collection plates, rate of air flowing through the air purifier and how much power is in the electric field are factors that can affect how much efficiency is mastered from the air purifier. Electronic air purifier filters with the capabilities of charged particles in order to clean the air were developed. After the process was developed, there were many other ways that the process was used including indoor electronic air purifiers.
Effectiveness and limitations of Electronic Air Cleaners
Electronics of air cleaning is an advanced, low maintenance solution, reliable, eco-friendly, deactivates 99% of captured particles, easy to maintain, quite operation, less frequent filter replacement required, simple maintenance and cost effective and efficient. Every air purification technology has its strengths and weaknesses. In which case, an air purifier that offers multiple technologies is generally best, in order to combine the advantages, and eliminate the disadvantages of each air purification method. Electronic air cleaners exhibit high initial efficiencies in cleaning air, largely because of their ability to remove fine particles. However, the continued effectiveness of electrostatic precipitators is highly dependent on keeping the collecting plates clean. Unless they also include some other mechanism as well, electronic air cleaners (of either type) target only particles, not gasses. This means that many common types of indoor air pollution, such as Volatile Organic Compounds, are not affected by them. Some electronic purifiers have been known to release ozone into the air, sometimes as a byproduct and sometimes intentionally. Ozone is a pollutant that can cause serious health problems to those who are exposed even to fairly small levels. As a result many companies have produced electronic air cleaners that do not emit ozone, and their marketing usually prominently reflects that fact. As indicated above, ion generators, unlike electrostatic precipitators, have no means of collecting pollutants inside the purifier itself. Instead, the particles settle elsewhere in the home, so that air pollution is reduced, but surfaces become dirtier.
