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Breathe easy: A good AC system should have a mixture of both return air and outside air.

Indoor air pollution can be as toxic as outdoor air pollution. Not just loss of productivity and employee efficiency, poor Indoor Air Quality (IAQ) affects human health to varying degrees, varying with the pollutant, its concentration and individual sensitivity. And since office goers work in these sealed environments (be it BPOs, banks, or beauty salons) for over 8 hours, indoor air quality is something we all need to be concerned about.

"The fact is, office equipment like printers, photocopiers and correction fluids, rugs and furnishings, and scents, hair sprays and cleaning agents release dangerous volatile organic compounds (VOCs) like formaldehyde into the air", points out Jagdeep Singh, Global head, DRI, that manufactures products and systems for energy recovery, IAQ, fresh air treatment, evaporative cooling and humidification. And ineffective filters in the A.C. ducts allow fungi formation and dust accumulation, and attract rodents and insects. Meanwhile, nitrogen dioxide, carbon monoxide, and radioactive radon can enter the air from certain building materials.

Take also into account the second-hand carcinogenic environmental tobacco smoke (ETS) hovering in the air. The US Environmental Protection Agency (EPA) estimates that ETS is responsible for approximately 3000 lung cancer deaths every year in the US. Lead and mercury based paints used widely are also worrying. Add to this re-circulating body odour and you encounter an air space which is getting loaded with pollutants by the minute.

Since air conditioned office spaces happen to be sealed, the space inside does not get reloaded with fresh air and fresh oxygen. There is a thrust towards energy-efficiency in air-conditioned buildings, but the level of ventilation with the external environment is rather low, notes Tata Energy Research Institute (TERI) which conducted a three-year long study in buildings in Delhi.

Ever noticed this? You find yourself yawning inside your cabin, and your eyes get a little watery and blood shot; but when you step outside and take a deep breadth, you find yourself refreshed and your eye sore fades; so, the discomfort was actually an effect of poor air quality inside your office. But these symptoms are just the tip of the iceberg. Poor indoor air can cause allergies, headaches, sore eyes, lethargy, colds and even respiratory disorders like asthma. The phenomenon has come to be regarded the Sick Building Syndrome. A World Health Organisation report in 1984 suggested that as many as 30 per cent of new and remodelled buildings worldwide might generate excessive complaints related to indoor air quality.

"America has 35 buildings classified to be sick; no single building in Chennai has been reported sick so far, but that doesn’t mean that there is no cause for concern", says air conditioning consultant, M. H. Lulla. "We are heading towards that kind of a scenario because of the indiscriminate use of toxic synthetics, the import of cheap building material from China without knowing what it contains, etc".

“The answer to any kind of pollution remains dilution. So, ideally, we need to draw in fresh air,” says Lulla. A good AC system should have a mixture of both return air and outside air. The American Society of Heating Refrigeration and Air-conditioning Engineers (ASHRAE) stipulates that each person in an office needs at least 15 to 20 cubic feet of fresh air per minute in an office. Commonly, Carbon dioxide levels are used as an indicator to evaluate IAQ and the ventilation in the building. ASHRAE recommends that indoor carbon dioxide levels do not exceed 550--700 ppm above outdoor ambient levels.

On the flip side, drawing in outside air will increase air conditioning requirement. This can be toned down by use of heat recovery devices which facilitate heat exchange between the incoming fresh air and outgoing cold air. This may be expensive on the initial costs, but saves recurring energy costs in the long run, M. H. Lulla says.

"Other things that can be done to enhance IAQ would be the replacement of faulty carpeting and water-stained ceiling tiles, smoking restrictions, restrict use of paints, adhesives, solvents, and pesticides to well-ventilated areas and during periods of non-occupancy, and of course, proper and frequent maintenance of HVAC systems", advises air conditioning consultant, Ramesh Karanth. The air handling equipment should not hold water, and the drain pan should be dry all the time, insists M H. Lulla. And of course, overhaul old and inefficient filters. Some air-conditioning consultants advocate circulating ozone for indoor air purification. But, this could be a case of playing with fire as ozone can react with your lung tissues.

Since it is as basic as the air we breathe in, maintaining IAQ is something architects and occupants alike need to be concerned about. This becomes even more crucial as most of us spend about 80 per cent- of our lifetime indoors.

Homes too can suffer from poor IAQ. Here is how to ensure that the IAQ in your homes is up to the mark.

•Ensure cross-ventilation.

•Service the filters and humidifiers of your AC regularly.

•Install special high efficiency filters in the HVAC system.

•Use exhaust fans in areas like kitchens, bathrooms.

•Bring in fresh air using reverse exhaust fans.

•Service your electric chimney.

•Don’t smoke inside home.

•Don’t idle or warm up vehicles inside garages.

•Use products containing organic solvents sparingly, and according to label directions.

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