It is perhaps ironic that the office of Nirvana Being, a company that provides air pollution solutions, is located in an industrial area that has a power plant on one side and a massive landfill on the other. “We have kind of made an oasis in the middle here. A place where air quality is better than what is outside," says Jai Dhar Gupta, 45, who started Nirvana Being in January 2015.

The air quality within the office is controlled with the help of gadgets such as the Laser Egg air quality monitor and Airgle air purifier. There’s also a “green room", which is a meeting room as well, that is full of plants. The only thing that is not real in the room is the artificial grass carpet.

Also read: Breathe sensible

Gupta, who studied corporate finance and environmental science and graduated from Wharton in 1994, calls Nirvana Being a one-stop shop to fight air pollution. The company is known particularly for bringing the Vogmask, a premier filtering mask, to India. Gupta used the mask himself for the first time in November 2014 when he faced lung complications while preparing for a marathon.

He keeps facing questions about picking the right air purifier or mask, especially with Diwali round the corner. “Every time someone asks me that, I ask them: How much is your life worth?" he says.

The sad bit, he says, is that people in India have learnt to live with bad air and respiratory problems. Sometimes, it is good to look at things from a scientific angle, he adds. “Once the AQI (air quality index) goes above 300, none of the big-name brands available in the market will work because they were not built for that environment. They were built for a city like London, Singapore or Paris on really bad air quality days. These places stop vehicular traffic and declare a health emergency in case the AQI reaches 180 (AQI should ideally not cross 50). In Delhi, 600-700 is considered normal," Gupta adds.

Gupta tells us how to pick the right air purifier. Edited excerpts:

How does one choose the right air purifier? Should people keep an eye out for certain filters or clean air delivery rate?

Delhi’s No. 1 problem is a high particle count. Our air is laden with ultra-fine particles and it is all to do with combustion. For an environment like Delhi, you need an Ulpa (ultra-low penetration air) filter. There’s Hepa (high efficiency particulate air), which filters down to .3 microns. Ulpa filters 40 times more than a Hepa air purifier.

Your air purifier has to have a pre-filter. Your main filter catches all the big particles and it gets choked in six-eight weeks. The machine becomes useless and filters are really expensive. It is also an environmental disaster to keep replacing your filters every two months.

The air purifier needs to be the right size for a room. It must do five-six air changes of the complete volume of air in that room in an hour to get the job done.

So, get an air quality consultant to come and see your rooms. They will tell you the right machine for every room. It is also important to have an activated carbon filter in your machines because that’s what gets rid of all the gases and odour.

What about anti-pollution masks?

Don’t buy disposable ones. You are going to create more pollution. You’ll wear a disposable mask, throw it in the evening and it will go to a landfill and get burnt. Buy only reusable masks.

The most important thing is the filter. In Delhi or north India, you need a mask with an N99 filter. Our particle levels are so high that an N95 mask will not get you into the World Health Organisation safe level of particle count. You also have to have an activated carbon filter in the mask.

Exhale valves are also important, especially if you are in a humid environment. If your mask does not have a proper exhale valve, you’ll have moisture dripping down your chin.

A good test for an anti-pollution mask is the fit. If it doesn’t fit you, don’t buy it. One size does not fit all. Comfort is very important.

Does geographical positioning change the need for an air purification device?

The needs will be different. Mumbai’s air quality problems are very different from Delhi’s. Humidity is one of the problems in the Mumbai air. The other problem is kitchens not being ventilated properly. The city is more dense. The particle count in Mumbai is 40-50% of what we have in Delhi. Most of their air quality problems are because of density and moisture.

Do you think the topic of air quality is taken for granted?

We have to understand that air is the single biggest raw material you put in your body every day. We might be having a kilogram of food or water. But we consume 14kg of air. Be aware of your surroundings. You’ve got a bunch of apps that keep updating you about the air quality around you. If you ever see the air quality levels go above 180, that’s when the alarm bells should start ringing. While you are indoors, make it a point to air out the rooms during the warmest time of day and allow fresh air inside.