AC: comforter or contaminator?

by Afreeha Jawad

In the aftermath of the industrial revolution when factory workers were relegated to degrading working conditions, it was Hawthorne who put forth his theory of a good work environment for better output. Those that speak today of Indoor Air Quality stand to facilitate and compliment him in his endeavour though Hawthorne himself lived and died at a time when state-of-the-art cooling systems were let alone not heard of, not even in existence.

The Information Technology Institute's (formerly CISIR), Industrial Ventilation and Essential Oils Division led by Nalini Amerasinghe has come a long way since 1980 when she and her staff set forth on the provision of Indoor Air Quality or IAQ services.

According to chemical engineer Thilak Gunasekera, they on request have rendered such services to numerous giant enterprises now doing well in maintaining indoor air quality popularly called IAQ.

To those that believe air-conditioned environments to be the cleanest, both these staffers have a one big 'no'. In fact they even believe such environs to be more polluted than the air outside.

External air pollution has been widely discussed overlooking IAQ - of which public knowledge is extremely poor.

According to them, a growing body of scientific evidence indicates that air pollution within houses, buildings and other confined spaces, such as air conditioned buses, can contain far worse contaminants than polluted outdoor air in even the largest industrial hot spots in the world.

The pollutants - primarily coming off indoor pollution, soil infiltration and air pollutants, restricted ventilation rates and entrapment of pollutants, lead many humans into what is now known as Sick Building Syndrome. Such persons, particularly the sick, elderly and infants, spend around 90 per cent time indoors and are victims of chronic diseases, not to forget respiratory and cardio-vascular diseases.

They also pointed out how even developed countries have failed to adequately address this problem though now a burning issue.

Offering much scope to the heating, ventilation and air conditioning design engineers, IAQ's importance even though at snail's pace is catching on in Sri Lanka with the ITI itself giving the lead into maintaining such air quality.

Three primary ways to air quality control are ventilation, source control and air cleaning. Apart from external contaminants brought inside, air quality problems caused by oxygen depletion reduces IAQ levels.

Carbon Dioxide or CO2 can also indicate unacceptable levels of more harmful gases or the depletion of oxygen - the recommended levels being 1,000 parts per million. At higher levels it induces drowsiness where the air also becomes hot and stuffy.

As humans take in carbon dioxide, the importance of head counts and indoor space cannot be overlooked. Carcinogens or cancer causing substances are significant contaminants the exposure to which is unnoticeable with short-term impact. However, in the long-term, even low levels of exposure may lead to severe irreversible health problems.

Noteworthy also is tobacco smoke - a major concern in maintaining Indoor Air Quality. Its role in lung disease - particularly cancer - has now been proven by research. Its impact on the non-smoker is also highlighted and now considered a violation of one's rights when resorted to by another.

Carbon monoxide - another indoor pollutant - is released off malfunctioning combustion appliances such as stove, heater or water heater and the exhaust fumes coming off an engine or motor vehicle in an enclosed space.

Certain disease causing organisms can be present in the building itself such as 'Legionella' that grows in warm water and could be dispersed into the air in water drops. Fatal, short-term pollutants are not noticeable except from their ill-effects.

Many indoor air contaminants such as allergens, volatile organic compounds, bacteria, viruses, ozone and particulates can cause skin and eye irritation. Many contaminants cause a cold like symptom and often mistaken for viral infection.

Many odiferous chemicals such as body odours, the smell of spoilt food and chemicals cause irritation and annoyance - affects productivity as well.

Ozone coming off equipment that uses ultra-violet light causes ionisation of air also is an indoor air pollutant. Ozone being highly toxic may even irritate the eyes and respiratory track.

Formaldehyde is usually given off from building material such as plywood, particle board and some carpets. Exposure to such may cause a wide range of health effects including headache, eye, throat and chest irritations.

Other indoor pollutants include asbestos - there is proven evidence of it to even cause lung cancer and mesothelioma, fibres such as fibreglass commonly used in the lining work of air-conditioning duct work, combustion particles from smoking, dust from clothing, paper and carpets, Raden and raden products of Radium-226 found in building material made of certain rocks and soil.

These men recommend more fresh air supplies into air conditioned rooms through the air conditioners itself to maintain clean air quality levels.

Restricting fresh air entry intensifies accumulation of contamitants.

"In our services we maintain a balance between fresh air and re-circulated air because every bit of fresh air coming in and is conditioned flushes out the pollutants," said Gunasekera.