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It’s That time of the Year Again – As the Temperature Dips, Delhi Air Quality Nosedives

Nippy air, slight chill, and that swift switch from summer to the onset of Delhi winter with our favourite jacket out of the storage – sounds cosy, no? But here’s a bite of reality – this fuzzy feeling is more often than not complimented with fits of sneezes, headaches and throat itches, and in some cases, breathing difficulties. Yes, that’s what Delhi winter is about. Air pollution, worsened and aggravated due to the deadly cocktail of dropping wind speed, air saturated with particulate matter and toxic fumes, made stronger with the smoke due to the stubble burning in the Northern states, spanning across the entire Indo-Gangetic plains.

Of course, as we all now clearly understand, our indoors aren’t any safer. Indoor air pollution is as deadly, and harmful, if not more, with hardly any scope for diffusion of the density of the toxicity. Whether it is the outside toxic air settling in and getting trapped, fumes from indoor cooking, free floating dust particles settled in different corners around the house, smoke from home incenses like agarbattis, or cigarettes, and the aerosol contents of our fragrances, they are all examples of what constitutes indoor air pollution. These issues, though common the whole year round, especially start to stand out in this period of the year.

How does it affect us? Research has clearly stated that prolonged exposure to these pollutants is likely to manifest in the form of increased health concerns, like coughing, wheezing, scratchy throats, itchy eyes, runny noses to name some common symptoms. In more serious cases, especially for people suffering from compromised lung functioning or any respiratory ailments, these can be potentially dangerous. Young children and elderly folks are especially vulnerable to these issues.

Newspapers and media are filled with dialogue on what’s been done or what’s being done to tackle the menace of air pollution; but honestly, we all realize the truth, right? Results are still far from visible, and we certainly can’t wait for them to kick in to protect ourselves.

Here’s where air purifiers can be of help, as their use helps lower the risk of developing poor air quality related health problems, besides safeguarding against worsening pre-existing health conditions.

So, What Do Air Purifiers Do, and How Do They Work?

Air purifying technologies can be of two types – active and passive. Active air purifiers release negatively charged ions into the air, which makes pollutants stick to surfaces, and passive purification uses filters to remove pollutants. Out of the two, passive technologies are usually more efficient, as they manage to permanently remove the pollutants from the air by filtering them out.

In a nutshell, air purifiers ‘purify’ the air in a closed space by sucking in the polluted air from your surroundings with the inbuilt fan, filtering out the harmful particulate matter, and releasing cleaner air for you to breathe in. The filters are made of materials like paper, fiber, mesh and fiberglass. Yep, it’s all about the filtration, folks!

Now, then, what is filtration and how does this work? Filtration is the process of sucking and trapping airborne particles by excluding them on basis of their size. The particles are physically captured from the air in the filter, thus leaving behind cleaner air. These filters are rated using Minimum Efficiency Reporting Value (MERV), which has been developed by the American Society of Heating and Refrigerating and Air Conditioning Engineers (ASHRAE), and ranges from 1 to 16, with 16 being most effective. This rating gives you an idea as to how well can the filter trap the pollutants that are as small as 0.3 microns and as large as 10 micros.

Different Types of Air Purifiers With Different Filtration Technologies

There are different types of filters, as listed below-

  1. HEPA filters – High Efficiency Particulate Arrestance (HEPA) filters have a very high (as high as 99.97%) success rate of removing particulate matter, including 0.3mm sized particles, mold spores, dust, and other larger particles, etc. They are believed to provide the highest level of protection in our homes, and are especially beneficial in cases of those suffering from allergies and respiratory issues.  However, they may not be efficient at filtering out gases, fumes and odours, as these gaseous pollutants are too small to be captured.
  2. HVAC filters – These filters with MERV rating of 14 or above, can capture up to 75% of particles between 0.3mm to 1.0mm. Although their efficiency rate is lower than HEPA filters, they can move significantly more amount of air in less time, which means that a filter with high MERV ranking may be more effective than a HEPA filter
  3. Carbon filters – Carbon filters are a good way to capture gases and Volatile Organic Compounds (VOCs) from the air. These are usually released from indoor plants, paints, or use of cleaning products around the house. HEPA filters along with activated carbon technology are an even more efficient and effective means of filtration, as they can tackle particles and gases both.
  4. UV filters (or Ozone filters) – These are enhanced filters which use short-wave ultraviolet rays to kill bacteria and viruses. . When air passes through the HVAC unit, the UV lamps disinfect it with germicidal radiation. UV filters are excellent for killing microorganisms that could be hazardous to your health, including mold spores. However, there’s a potential danger to their use, as they can transform oxygen to ozone, which can be hazardous to health as prolonged use may result in coughing, chest pain, and even asthma. Therefore, these are not a good option for domestic use, and best suited only for commercial or industrial use.
  5. Electrostatic filters – These use cotton and paper fibers to create static that act as magnet for dust and other airborne particles, stopping the particles from spreading through the home with the strength of their magnetism. These filters are disposable and reusable, thus one may wash and reuse these as well. The one drawback is it may be a struggle to capture larger particles like dust and mold pores.
  6. Media filters – These can provide more benefits than standard HVAC filters with high efficiency ratings. They are easy to maintain, and great for filtering bacteria and small airborne pollutants. They need professional installation, and are ineffective for odors.

Are There Many Types of Air Purifiers in the Market? Why Are Some More Expensive Than the Others?

Different categories of air purifiers have different capacities, and filtration qualities. So, an air purifier which is super efficient in a small room may not be efficient in a bigger room, and it may further reduce its efficiency if the room is more crowded. Similarly, the efficiency may be impacted if there are any openings or outflows in the vicinity. So, if you have left that window open slightly, don’t be surprised if the purifier isn’t showing a lot of change in the air quality!

Now, one might wonder about the disparate pricing for various air purifiers available in the market. While the basic technologies are primarily the same, factors like product effectiveness, efficiency, design, and the market placement of different brands play a key role here. What is equally important is the fact that not only may these purifiers be different in their capacity, effectiveness and performance, some of these products may also have additional, superior features and advanced technologies associated with them. For example, Xiaomi Mi Air Purifier 3 is generally considered an overall favourable product due to its strong HEPA filter, its performance and price affordability. On the other hand, a Dyson Pure Hot + Cool Air Purifier is priced considerably higher due to its superior advanced technology, features and capacity.

To Summarize,

It is true that an air purifier will not provide a lasting impact. You can LITERALLY SEE the air quality drop the moment you step out of your cocoon, open up your room’s door even for a second. But at least they give you relief for the period you are using one. If you switch them on during night, your lungs breathe in fresher air after the entire day’s exposure to particle laden air, thus providing them an opportunity to rejuvenate. In times like these where neither government nor any of our reputed research institutes have been able to make a breakthrough to tackle the problem in a more tangible manner, then we need to depend upon these tools and appliances which help us adapt better to our polluted environments, and make that little effort for the healths of our families.

About The Author

Kritika Mathur

Kritika Mathur is the Chief Editor at Sustainability Today. Her ability to perceive cultures, trends and people gives her the ammunition to understand the nuances of sustainability challenges. She also heads the strategy and operations at Envecologic. When not strategising, Kritika loves to read, bake and travel. She is also a star blogger!

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