Air conditioning systems today can be seen in almost all offices and in many of the residential spaces. Air Conditioners are cooling, heating, ventilating and disinfectant systems that provide health and comfort. However, the common myth among many people is that air conditioners alone provide good indoor air quality, but the fact is that they are neither effective in enhancing the oxygen quantity nor reducing the carbon dioxide levels which are main components of indoor air quality.
Increased levels of carbon dioxide and depletion of oxygen mainly affect indoor air quality. Now a days, indoor air is considered as more concerning health hazard than outdoor air.
Why oxygen levels deplete
Most of the air conditioning systems re-circulate a significant portion of the indoor air to maintain comfort and reduce energy costs. In today’s home or office environment, simply heating, cooling or filtering the dust particles by air conditioners is not enough to ensure a pleasant indoor atmosphere. If temperature is simply adjusted, air is filtered, and recycled it loses oxygen content over a period of time. Exposure to low-level oxygen environment may cause negative impact on health and lowers the operational efficiency.
There will be a significant demand for the indoor oxygen in the closed-door environment, where the air conditioners are running. Oxygen adequacy should be supplemented with outside air. Continuous inflow of up to 10% of fresh, filtered air into an air-conditioning system is required to replenish the required quantity of oxygen.
Why Carbon Dioxide levels increase
Carbon dioxide (CO2) is an indoor pollutant emitted by humans as part of human metabolic activity. High levels of Carbon dioxide may cause drowsiness, headaches, or may lower the activity levels of the occupants. The air conditioners do not remove carbon dioxide. High levels of CO2 indoors is an indicator of the inadequacy of outdoor air ventilation relative to indoor occupant density.
To enhance the indoor air quality CO2 level should be reduced. The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) recommend that carbon dioxide levels should not exceed 600 ppm than the outdoor levels in homes, 800 ppm in offices and 1000 ppm in schools.
It’s impossible for the occupants to check how much of this air is simply re-circulated air and how much is fresh air without using any instruments. But the technology today offers many accurate and inexpensive instruments to measure the carbon dioxide levels. Some of these instruments not only measure CO2, but also measure other factors such as temperature, relative humidity and other dangerous gases such as carbon monoxide.
Remember that carbon dioxide is heavier than the oxygen. So make sure that you place the ventilators, which suck out the carbon dioxide and other dust particles at lower level near the floor.
Strategy to improve indoor air quality
Both window and split type air conditioning systems are not effective in ventilation. They should be complemented by exhaust fan and some opened windows to provide enough fresh air. The distribution of air inside the premises can be enhanced using a circulating fan.
Central air-conditioning system is used to control humidity, and deliver fresh air into a building with many rooms. Make sure that each room has sufficient fresh air supply. Use circulating fan to enhance air distribution within the area. Remove if there is any obstruction to the ventilation inlet or outlet.
Some houseplants are known to reduce indoor air pollutants such as volatile organic compounds as well as carbon dioxide and carbon monoxide.