Saturday, October 28, 2017

The Air We Breathe





Over the past one week, I have been analyzing the market for air purifiers in the NCR Delhi region. It is just the right time of the year for an assignment like this - the quality of air here takes a nosedive with the onset of winter.

Today the reports of suspended particulate matter - especially PM 2.5 - were particularly alarming. It peaked at over 715 mg/m3 when the prescribed limit is below 60 mg/m3!

Just before the festival of lights, Diwali, farmers in Northern India harvest their summer crops and prepare their fields for the winter sowing season. Since it is too expensive to physically remove the post harvest residue from the fields they just burn it.  A huge cloud of smoke then slowly drifts over Delhi and settles down with all the smoke from Diwali firecrackers, turning the national capital into a gas chamber.

This year, a one-off intervention by the Supreme Court resulted in a ban on the sale of firecrackers, so there was a marginal reduction in the smog and haze, but it still left most of us teary eyed, and with a niggling irritation in the throat.

Pollution is not bad news for everybody. There has been a spike in the number of companies selling air purifiers, big advertisements in the newspapers point to the fact that 15 odd companies are all set to make hay while the sun shines dimly through the smog.

According to the Philips salesman at GIP Mall in Noida, air purifiers have been flying off the shelves as Diwali gifts. The company is barely able to keep pace with the demand. From what one could see, in their enthusiasm to sell, their glib sales pitch is also barely in touch with scientific facts.

"We human being consume about four kilograms of food everyday", said the Philips salesman, "But do we know that we also breathe in about 24 kgs of air, with all the pollutants in Delhi?" I did not know that. Having been under the impression that the volume of air is measured in liters or cubic feet or cubic meters, I have been trying to figure out the actual volume of air consumed by us everyday.

The World Health Organisation and US-EPA has some clear figures on this. Considering the fact that the air contains 20-23% of oxygen, and that an average human being breathes in about 0.5 liters of air with each inhalation. At about 20 inhalations per minute, we are consuming no less than 6-8 liters of air while we are sitting around doing nothing. This jumps up to 60 liters/minute while running at 5 miles/hour. So it turns out that we are breathing in no less than 14,400 liters of air every day (0.5 * 20 * 60 * 24). This volume would take up all the space in a room measuring about 500 cubic feet!

The Philips salesman might have been talking through his hat, but there is no denying the fact that most of us are unaware of the sheer volume of contaminated air entering our lungs every day!

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LINKS and REFERENCES

*  WHO  Factsheet - Ambient air quality and health - http://www.who.int/mediacentre/factsheets/fs313/en/

* USA - California Env Protection Agency research - https://www.arb.ca.gov/research/resnotes/notes/94-11.htm

* YouTube video - How much oxygen does a person consume/day? - https://www.youtube.com/watch?v=t-QYVKYKyfg

* https://www.quora.com/How-much-volume-do-we-inhale-and-exhale-in-a-day

* Oxygen intake - https://health.howstuffworks.com/human-body/systems/respiratory/question98.htm



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