Say ‘aye’ if you have trouble breathing right now. If you are living in Delhi or the National Capital Region, chances are you are mentally raising your hand.

Last year in May, the New York Times’ (in)famous article of an eight-year-old’s struggle to breathe in the capital’s toxic air, set off a storm of protests. The critique might have been a slightly over-the-top, the outrage it elicited was a classic case of shoot the messenger; but the consequence was that the sales of expensive indoor air purifiers in the capital went through the roof.

Indoor air can be 3 to 5 times more polluted than outside (source: Centre for Science and Environment) - no wonder, the air purifier market in the country has gone from nothing to Rs 150 crore in the last couple of years (source: Philips India). The market is flooded with options of models from Rs 3,000 to a whopping Rs 90,000. But do they work? Besides your budget, what else should you keep in mind when zeroing on a product?

Scroll below for the complete guide:

How Do Air Purifiers Work?

Air purifiers work in the same way as water purifiers. The processing of machines is pretty simple, it all boils down to how fine the filter is. These devices clean the air by removing impurities such as particulate matter, smoke, pollen and other irritants.

All purifiers come with pre-filters, which remove large dust particles and other things like hair. The activated carbon filter and the HEPA-filter, an international standard for air particle filters, work to remove impurities and reduce odour.

Are They Effective?

The answer depends upon a combination of factors, like, does the cleaner remove only coarse particles or the fine ones as well, is every nook and corner of your house covered, how often do you get the filters changed.

So if you can afford to buy one for every room of your house, you’re in for some luck. Some high-end private schools in Delhi have installed central air purifiers.

Running air purifiers is a costly affair, depending upon the level of pollution in your city, the filters have to be changed often or the toxicity of air might erode its internal machinery.

More Harm Than Good?

Air purifiers clean the indoor air but there is no medical literature to prove that they control the incidence of asthma and other respiratory illnesses.

The ionic range of purifiers introduce ozone in the air to neutralise certain pollutants - now doctors aren’t sure if this is a good thing or bad.

Ozone is a known lung irritant which can cause severe chest burning. However, manufacturers claim that ozone turns harmful only when it mixes with dust particles and not in clean air. So the big question – if your entire home is not protected with purifiers, the ozone is bound to mix with dust - what happens then?

Options in the Market

Priced at Rs 3500 is the Jugaad Air Purifier it’s a DIY, cheap, frugal, no glam, no glitz solution in the market.

This system is just a HEPA-filter and a fan, because if you break it down to the basics, that is all there is to an air filter. The company has sold more than 60,000 units in over 16 countries, including India, in the last two years.

The ones in the Rs 15,000 to 25,000 range have a superior design, are well-built, come with many modes and control systems.

The clean air delivery rate is highest in the Rs 30-40,000 range. From Philips to Sharp, there are many players in the market, opt for the one which comes with a pre-filter so the life of the HEPA-filter can be enhanced.

The Camfil air purifier is the most elite machine in the Indian market - priced at Rs 90,000, it is powered with the best molecular filtration technique which claims to clean up 99% of the toxic pollution within minutes.

So before you shell out the big bucks, calculate the monthly maintenance expenditure and the spike in your electricity bill. The pollution in Delhi is undoubtedly bad, but no medical literature has proved that breathing air from purifiers will increase your lifespan.

Also Read: Cleaning Capital’s Air: The Problem is Pollution, Not Congestion