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INDOOR AIR QUALITY (IAQ):
DEFINITIONS and MYTHS
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People in the United States spend up to 90% of their time inside home, offices and buildings. It is believed that the adverse effect of indoor pollutants can significantly affect people’s health and so Indoor Air Quality (IAQ) has become a major concern in recent years.
EPA indicated that Indoor Air may be up to 5 times as polluted as outdoor air. The trend is worsening as houses are built tighter thereby reducing air exchange between outside and inside air and avoiding heat loss in the winter and heat gain in the summer, altogether increasing energy efficiency but also concentrating indoor air pollutants.
There are many types of Indoor Air Pollutants including Volatile Organic Compounds produced by building materials, furniture, paint, carpet, pesticides and cleaning materials, Molds and other Biological Contaminants like dust mites, bacteria and viruses, Noxious Gases like carbon monoxide, Toxic Components like asbestos, lead and radon and Allergenic Particles like dander and pollens.
Unfortunately many noxious gases are neither visible nor odorant so that we need to use special monitoring devices to let us know of their presence. Carbon Monoxide for example is a colorless, odorless and tasteless gas which is slightly lighter than air but highly toxic. OSHA (Occupational Safety and Health Administration) limits long-term workplace exposure levels above 50 ppm. Similarly due to the health risks associated with carbon dioxide exposure, OSHA says that average exposure for healthy adults during an eight-hour work day should not exceed 5,000 ppm (0.5%).
In fact, the air filter in your Heating and Air conditioning systems are meant to protect the HVAC system the same way that your car air filter is meant to protect your car engine and not the cabin air quality. However, as a side effect, some air filters of higher quality will improve the IAQ provided they are properly sized, correctly put in place and frequently replaced.
The ability to filter particles by air filters is measured in MERV. The higher the MERV number, the higher filtration capacity.
Basic mesh filters – blue or green – (MERV below 4) trap particles 10microns or larger Therefore they let many of the air contaminants go through and do not qualify as improving IAQ. Pleated air filters with MERV between 5 to 8 are better for your HVAC system and can trap between 30 to 80% of particles as small as 3 microns, thereby reducing the amount of large pollutants of indoor air.
The EPA (Environmental Protection Agency) declares that duct cleaning has never been shown to actually prevent health problems. The agency recommends doing ducts cleaning only when - and if - needed and even mentions replacing the ducts rather then cleaning them in some cases. The fact is that Air Ducts in most homes are made of flexible ducts which are circular pipes, made of fragile material, losely connected to one another and holding together thanks to some duct tape. As these ducts age, they become sensitive to both shaking (glue dries out and ducts open up in your attic) and poking (outside lining becomes brittle and breaks easily so air flows to your attic). So Air Duct cleaning for home may not improve the IAQ while potentially causing significant damages and air leaks to the inhabited space.
Most room cleaners are unable to circulate enough air in a given time frame to catch all the contaminants of a single room, let alone of a complete house. Moreover many of them charge the particles which make them stick to walls, furniture and carpets (making your home looking dirty) and never go through the filtration systems (meaning the air pollutants go back into the air when you touch the surfaces of your home). Another drawback of ionization is the production of ozone, a lung irritant. However some room cleaners using HEPA air filter and Activated Carbon filters do a good job at capturing air borne particles like dander and mold spores as well as gases and odors provided they are placed in a space of a size compatible with the room cleaner capacity and the filters are replaced sufficiently often.
However, some room cleaners have been approved by AHAM (Associate of Home Appliance Manufacturers) and tested by third party for their ability to at least remove three specific air pollutants. With Room Air Cleaners as with many appliances, one gets for what one pays for. Additionally, room air cleaners should be use according to the manufacturer’s guidelines to have some efficiency in regards to the limited space in which they work.
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