We rose to touch the skies and fought to tame the seas;
Conquered creatures far and wide ‐ turtles, swans and bees
Somewhere we but lost our way, got too 'civilized' to care
Now we pay for 'sparkling water' and gasp for breath of air !
In recent years, much has been said and written ( though little has been done really ! ) to clean up the air we
breathe. So much so that 'SP 2.5 and SP10' are now household words in our urban concrete jungles. Come
October each year, air purifier sales soar ( in National Capital Region) . The need to have a 'winter home' ‐
away from smoggy skies of city ‐ has triggered a new real estate demand in past few years! Yet much of this
conversation ..... 'of having fresh indoor air '..... is incomplete till we dive deeper to understand the true
meaning of 'fresh indoor air' holistically.
Some fundamentals first!
Freshness of indoor air has many aspects ‐ besides 'dust and smoke' . Best indoor air needs to imbibe the
qualitative aspects ( physical, chemical and electrical) of the air we find in nature .... in thick woods or by a
gurgling stream. 'Freshness' of air, therefore refers to all the following being in balance :
absence of dust and mould particles
a balance of +ve and ‐ve ions in air
proper ration of O2 vs CO2
optimal humidity and temperature
Often to prevent outdoor 'polluted air' from entering inside and to keep inside 'cool' air from escaping
( especially in summers) , we 'seal' our buildings thoroughly. This is our spontaneous response ‐ be it residence
,workplace or institution, ( including clinics of many doctors and many gyms too !). Since all living beings
( except plants!) exhale carbon‐di‐oxide, depending on the number of occupants and their activity ), CO2 levels
in any enclosed space increase ‐ gradually but consistently‐ overtime .It is not widely known that the impact of
having low oxygen levels ( and higher carbon‐di‐oxide levels) in the indoor air is as detrimental ( if not more !)
to our health as the presence of pollutants. It needs to be understood that even dust filled outdoor air could
have more oxygen than our indoor air!
Carbon‐di‐oxide levels vs cognitive performance
According to a study from the Harvard T.H. Chan School of Public Health in 2015 (https://www.hsph.harvard.edu/news/press‐releases/green‐office‐environments‐linked‐with‐higher‐cognitive‐function‐scores/) a direct correlation between the low level of CO2 in indoor air to the high level of cognitive performance was established. Following graph is the result of this 'double blind' experiment.
When researchers looked at the effect of CO2—not normally thought of as a direct indoor pollutant—they found that, for seven of the nine cognitive functions tested, average scores decreased as CO2 levels increased to levels commonly observed in many indoor environment.
In another report, the US Green Building Council commenced a meta‐study in 2003 and concluded that delivery of fresh air and reduced levels of pollutants improves productivity by 11%.
The Catch 22 situation......and the way forward!
The paradox is ‐ We cannot let outdoor air to come into our spaces due to high outdoor pollution, yet we need outdoor air to balance the O2 and CO2 inside our building! Following broad measures that can help :
Space design , right at the concept level needs to incorporate systems that ensure clean , fresh air ‐ even in non‐conditioned spaces or areas having split A.C provisions. While centralized A.C buildings address this by installing TFA ( treated ‐fresh‐air) units, however, it is not commonly known that spaces with split air conditioners have no possibility to intake fresh outdoor air!
Opening all windows for an hour in morning ( or noontime in peak winters) and an hour in evening....better if exhaust fans are used to facilitate air exchange. A common belief that air bleeding through door and window gaps is sufficient for adequate air change to happen is also very misleading. We need much more air exchange to achieve required oxygen levels!
Some plants( like mother‐in‐laws tongue, areca palm, money plant etc.) are very effective in not only producing oxygen but also cleaning the volatile organic compounds found in indoor areas. Usually the number and size of plants per person to achieve this balance is high and often impractical....yet it is achievable with proper planning.
'Air' is one of the five elements that sustains life on earth. It's time we also understand that clean and fresh air is not only needed to sustain life but even to 'live our life to it's full potential'!