Indoor Air Quality
We spend more than 85% of our lives indoors, be it our own bedroom, dining room, classrooms, college libraries, restaurants, and the list is endless. Therefore, it is vital to maintain an excellent quality of indoor environment. Researches have shown that offices that make diligent efforts towards maintaining a good indoor environmental quality have happier, healthier, more intelligent employees and this leads to higher productivity…
- Arjun Kamal
Are we breathing right? Is the indoor air more pure and better than outdoor air? Can air conditioner help in purifying air? Absolutely not! Especially in metro cities like Delhi that has emerged as the most polluted city in the world. People living in crowded metropolitan cities are unaware that they are breathing in air that is far more polluted than one can ever imagine. This is wreaking havoc with their minds and the ability to think and behave, how they differentiate between wrong and right. Poor quality of indoor environments causes various health problems and also results in the sick building syndrome. What’s even more disturbing is that indoor air can be much more polluted than the outdoor air, therefore it is extremely essential to know about its quality. One should learn how to enhance the quality through various healthy practices.
We spend more than 85% of our lives indoors, be it our own bedroom, dining room, classrooms, college libraries, restaurants, the list is endless. Therefore, it is vital to maintain an excellent quality of indoor environment. Researches have shown that offices that make diligent efforts towards maintaining a good indoor environmental quality have happier, healthier, more intelligent employees and this leads to higher productivity. Schools following this practice have smarter students with high enthusiasm towards academics and other extra-curricular activities.
Our body needs a certain amount of balance between carbon dioxide (CO2) and oxygen (O2). When they are in balance within a specific range of ambient temperature, the body functions in the most efficient way. The person remains calm and does work faster than he would do in a polluted environment or in an environment that has undesirable temperature.
When we breathe in polluted air, the brain gives the body signals that something is wrong with the environment making us feel restless and uneasy. People who continue to work or live in such environment become the victim of stress and depression. This results in lower productivity in a given period of time. Often, crime also roots from such areas having inhospitable environments.
There is a simple method to understand this phenomenon. A brain can do a limited amount of work in a given period of time. Picture this. Everything is in balance, the air temperature and the pollution levels. Your body will feel right, you will do your work without getting stressful or uneasy. On the other hand, when the pollution levels and temperature is very high, your brain will have to do more work to make you feel better. The energy that would have gone completely in doing creative and productive work would be lost in regulating your body’s temperature and stress hormones. Here is where the term IAQ i.e. indoor air quality comes to effect.
Indoor air quality is a part of indoor environmental quality which comprises of thermal comfort, lighting, visual quality and acoustics too.
Let’s go back to our school days. In our science class we studied about the effect of carbon dioxide on the human bodies. When the concentration of carbon dioxide increases in our bloodstream at levels above 1%, dizziness occurs. At levels of 5% the body experiences more dizziness, shortness of breath and panic attacks. In high concentrations this gas can cause drowsiness, suffocation, headache, fatigue and unconsciousness.
In an indoor environment, the CO2 that we exhale must be taken out of the room. CO2 as we know is a harmful gas for human beings which is also known for the notorious green house effect.
Let’s understand how heat and dust move through air. It’s a fundamental law of nature that energy always travels from high concentration to lower concentration. When a room is cooler than outside, then heat energy from outside will enter in. Similarly, during winters if the room is warmer, then heat will flow from interior to exterior. Same principle applies for dust particles and pollutants. If there is a nallah near a roadside, we can smell foul air because the nallah is the source of that bad smell (having high concentration) and air on the road has low/or no speck of the foul air particle of nallah in it. So, the polluted air moves from the nallah to the roadside air.
In the same way, in our rooms, over a long period of time dust and pollutants get accumulated between the tiny gaps in the fibres of bed sheets, curtains and other objects like soft toys, canvas paintings, carpets, cushions, wall hanging made of jute, etc. When we breathe in, these dust particles move into our lungs which were free form it because of low concentration.
Dust also gets collected in the ventilation systems e.g. the vents of the air conditioning ducts. Moreover, this situation when gets worsened with moisture getting accumulated, leads to growth of harmful microbes like moulds and bacteria in the buildings which leads to deterioration of indoor air quality.
Dust allergies are actually allergies to dust mites — microscopic pests that need moisture to survive. Dust mites feed on human skin and live in bedding, pillows, mattresses, stuffed toys, upholstery, and carpets. Upholstered furniture should be vacuum cleaned regularly to prevent accumulation of dust. Bed sheets and cushion covers should be washed weekly to keep off dust. To prevent building of moisture in your building, keep a regular check on leakages during the seasons of rains and high humidity.
You are more prone to wheezing, coughing and asthma if your house has dampness even if there is no growth of moulds. Roofs, foundations and basements should be checked at least once a year for leaks or moisture. Wet rooms like bathrooms, kitchens and toilets should be vented properly. Use a chimney in your kitchen to keep fumes and smoke emissions due to cooking away from entering other habitable areas in your house.
All the windows of your house should be openable and placed efficiently to facilitate natural ventilation with regular air changes as well as natural light. The national building code prescribes areas within 7.5 metres of windows as naturally lit.
Air can be further prevented from getting polluted by using a decent particle filter or air cleaner in the air handling system to keep the air dust free. It also keeps away dust from entering the ductwork. Regular cleaning of filters should be done. They should also be checked periodically for replacement.
Besides air quality, maintaining an ambient temperature is also necessary to provide an ideal indoor environmental quality.
Whatever work we do, whether it is lifting a book off the table or walking a few steps to switch on the light, produces heat. Studies have shown that only 20% of the energy is used in doing any work by our body. The rest 80% is dissipated as heat. If this heat is not taken away/off from our body, then we feel uncomfortable.
You have all experienced this. We suddenly feel happy and relieved if we step into an air-conditioned showroom after walking in an uncomfortable hot outdoor environment. To dissipate the heat naturally from the human body, windows should be kept open to ensure cross ventilation in non AC rooms. The placement of the windows should be such that the air flows across the human body height and not above it as in near the ceiling.
If the air will flow through the surface of the body then the heat will be readily and easily taken off. Moreover, CO2 inside would also be replaced by outside fresh air through ventilation.
Ventilation is a necessary component for maintenance of indoor environmental quality. It is measured by the rate of flow of outside air getting inside the building environment. It is typically expressed in cubic feet per minute (cfm) or litres per second (L/s). Other units to assess ventilation rates are per person (cfm/p), per unit floor area (cfm/ft) or air changes per hour (ACH).
National building code of India prescribes following air change rates for different building types
ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers ) prescribes 15cfm of outdoor air per person as the minimum ventilation rate to decrease transmission of microbes and other agents of infection. This means if there is one person in the room, then 15 cubic feet of fresh air per minute should enter the room.
You should keep opening windows regularly for proper ventilation of your rooms. Exhaust fans also help a lot in removal of foul air, especially in bathrooms and toilets.
Human body needs oxygen and air at ambient temperature to function in the most efficient way. Air conditioners and natural ventilation can be used for maintaining ambient air temperature. But what about fresh air especially on days when there is lot of dust and pollution levels are also high? You can switch on your ACs for maintaining a cool and calm room environments but what about oxygen levels in the room? We must devise ways to increase oxygen levels in the room.
Plants are often used indoors for aesthetics. But do you know that you can also grow fresh air with three commonly available plants? These are
• Areca palm (Chrysalidocarpuslutscens)
• Mother in law’s tongue (Sansevieriatrifasciata)
• Money plant (Epipremnumaureum)
Areca palm converts CO2 to oxygen. One should take these plants outdoors every three to four months. Mother in law’s tongue , which is also known as bedroom plant can convert CO2 to oxygen at night. Formaldehydes and other harmful volatile chemicals in air can be removed by Money plant. Plants can also be incorporated in a vertical fashion in green walls so as to provide effective regulation of indoor air quality through removal of volatile organic compounds and other harmful gases. These compounds are known to cause pollution which leads to respiratory problems and allergies. Plants can also be incorporated in a vertical fashion in green walls so as to provide effective regulation of indoor air quality through removal of volatile organic compounds (VOCs) and other harmful gases. These green walls are walls which are covered with vegetation . VOCs are known to cause pollution which leads to respiratory problems and allergies.
Such compounds are found in paints and other building materials, like, wood, steel, glass, plastic, leather, PVC, etc. While buying materials for your home, do check the VOC content in the technical specifications list on the packet. It should be within permissible limits.
Therefore, use these techniques in your rooms to breathe fresh and live for long. Lots of researches and studies have shown that the air quality also shapes our DNA which eventually influences our personality and our behaviour. Now you can very well imagine what clean air can do to us.
(All illustrations drawn by author)
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