Air pollution has become one of the most serious issues of the 21st century. With rapid industrialization and urbanization, one thing that has taken the most brutal hit is the nature: the environment. With modernization comes luxury, with luxury comes comfort and what could be a better example of comfort than having a personal car? After all, who likes to travel in the public transport by choice, isn’t it?
Since most urban cities nowadays have two or three earning members per home so affording a car isn’t that difficult. In fact, the report released by the Delhi government shows the number of registered vehicles increased from 8.8 million in 2014-15 to 9.7 million in 2015-16 — a spike of 9.93% and the highest in eight years.
What these alarmingly high figures of cars running on the roads illustrate? It illustrates the quality of air that is going into our lungs with every breath. According to an IIT-Kanpur report, toxic exhaust fumes from vehicles constitute 25% of the city’s air pollution. The latest government data shows 6,502 people died of respiratory diseases in 2015, making it one of the leading causes of death.
That's the reason why today there are more and more air purifiers for smoke are sold.
Air purifier buying guide - The Basics
There are multiple allergens in the atmosphere including smoke, dust, pollen grains, bacteria, viruses etc which can not be seen with the naked eye but are extremely damaging to the lungs and the immune system. The air inside a typical home is generally dirtier than the air outside, because a house can be a source of air contaminants. Moisture can lead to the development of molds and spores then air conditioners circulate the dust particles and bacteria throughout the house. Pollen grains and other outdoor allergens can blow in through open doors and windows and become caught in carpet or bed sheets.
Related post: Best air purifiers ozone free.
Air purifiers filter allergens and pollutants which may or may not be visible to the human eye. To remove these allergens, air purifiers typically use filters.
Some of the most commonly used filters in an Air Purifier are:
- Activated Carbon
A HEPA or the High Efficiency Particulate Air is a type of mechanical air filter; it works by forcing air through a fine mesh. The fibers of the mesh are typically composed of fiberglass and possess diameters between 0.6 and 2.5 micrometers which trap harmful particles including smoke, dust, pollen grains, tobacco, bacteria etc.
To put it simply, HEPA filters trap air contaminants in a complex web of fibers. Depending on the size of the particle, filtration of contaminants happens in the following ways:
- Inertial Impaction and Sieving
Larger contaminants are trapped via inertial impaction and sieving. The particles either collide with the fibers and get trapped or are trapped while attempting to travel through the fibers.
Medium sized particles, as they move through the filter, are grabbed by the fibers via interception.
Smaller particles are dissipated as they travel through the filter and eventually collide with a fiber and are trapped.
Related post: Do air purifiers remove allergens.
Activated Carbon Filters
Activated carbons are small pieces of carbon, typically in granular or powdered block form, that have been treated to be extremely porous. Vast surface area of the activated carbon enables these filters to adsorb exponentially more contaminants and allergens than traditional carbon. Contaminated air enters the filtration system, passes through the active carbon, undergoes adsorption, and leaves the filter after getting purified.
Air purifier buying guide - The Advanced
Now, having learnt about the working of the air purifier and the various filters that are used in it, let’s proceed to learn what Clean Air Delivery Rate (CADR) value of the air purifier should you go for depending upon the area of the space that you wish to purify.
For installing the air purifier in a bedroom having area up to 350 square feet, go with an air purifier that provides a coverage area of at least 370 to 400 square feet with the CADR value between 150 to 250 metre cube per hour.
For installing the air purifier in the living room having area in the range of 350 to 700 square feet, purchase an air purifier that provides a coverage area in the range of 400 to 750 square feet with the CADR value of 250 to 350 metre cube per hour.
For installing the air purifier for purifying the entire house i.e. for areas beyond 700 square feet, go with an air purifier that provides a coverage area in the range of 800 to 1200 square feet with the CADR value of 400 metre cube per hour and beyond. If you can't find one for you, let's check best large room air purifiers.
In addition to this, what one must ensure is the level of noise produced by the air purifier when in use is under permissible limits. As a rule of thumb, noise levels below 60 dB are considered safe for prolonged use.
Having said that, let’s proceed to learn how some brands (names not taken) cut manufacturing costs to maximize their profits and in return provide an inefficient product to the consumer which can cause irreversible damage to the consumer’s health.
Using a below par HEPA filter. HEPA filter is one of the major components of the air purifier and hence this is also one of the favorite areas of the manufacturers to cut costs. What they do is, they deploy a poorly built and inefficient HEPA filter in the air purifier that are not potent in trapping the numerous allergens that are present in the air and hence the contaminants stay unaffected in the air you breathe which cause irreversible diseases including stroke, lung cancer and asthma.
Using a low grade fan. The effectiveness of an air purifier depends upon the speed settings of the fan and the wattage of the motor. Now, what some brands do is, they show a higher capacity of the air circulating fan on paper, so as to fool the innocent buyers. However, in reality the fan speed of such air purifiers is extremely low and thus the clean and purified air is not able to circulate to a large area which in turn leaves the air in the far off spaces unclean and full of harmful disease causing allergens.
Air purifier buying guide - The FAQs
Here are the most common questions: