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Poor indoor air quality can have a significant impact on people’s lives, especially those who are most vulnerable:
infants and children, pregnant women, the elderly, and those who have chronic illnesses.
Steps can be taken to help improve indoor air quality at home, the workplace, and in other indoor environments for a genuine healthy living.
Let’s do some "Experiments and Observations on Different Kinds of Air" as Priestley (Oxygen's father) would say.
The Indoor Air and Your Health
Air purifiers are used to reduce the concentration of these airborne contaminants and are especially useful for people who suffer from allergies and asthma. They also reduce the need for frequent household cleaning.
Air purifiers use a small amount of electrical energy, causing some expense and environmental effect.
When selecting air purifiers, you are influenced by several factors besides cleaning ability. These include possible hazardous gaseous by-products, noise level, frequency of filter replacement, electrical consumption, and visual appeal.
Advanced Technology In Air Purification
Improving the quality of the air we breathe improves our health and well being. Several different processes of varying effectiveness can be used to purify air.
Ozone production is typical for ionizing purifiers and has received much attention recently. Although high concentration of ozone is dangerous, most ionizers produce low amounts of ozone (<0.05 ppm).
The noise level of a purifier can be obtained easily through a customer service department and is usually reported in decibels (dB). The noise levels for most purifiers are low compared to many other home appliances and are not expected to cause hearing loss. However, purifiers are expected to operate over long periods of time. Therefore, even a moderate level of noise can be disturbing to some people.
Frequency of filter replacement and electrical consumption are the major operation costs for any purifier. There are many different types of filters; some can be cleaned by water, by hand or by vacuum cleaner, while others need to be replaced every few months or years.
Some purifiers are certified as energy star and are energy efficient.
HEPA technology is often used in portable air purifiers as it removes common airborne allergens. The Department of Energy has rigid requirements manufacturers must pass to meet HEPA requirements.
The HEPA specification requires removal of at least 99.97% of 0.3 micrometres airborne pollutants. Products that claim to be "HEPA-type", "HEPA-like", or "99% HEPA" do not satisfy these requirements and may not be tested in independent laboratories.
Bio-medical applications
HEPA filters are critical in the prevention of the spread of airborne bacterial and viral organisms and, therefore, infection. Typically, medical-use HEPA filtration systems also incorporate high-energy ultra-violet light units to kill off the live bacteria and viruses trapped by the filter media. Some of the best-rated HEPA units have an efficiency rating of 99.995%, which assures a very high level of protection against airborne disease transmission.
Air ionizers and ozone
As with all health-related appliances, there is some controversy surrounding the claims of certain companies, specifically involving ionic air purifiers.
Particularly, some ionic air purifiers generate the pollutants ozone (an energetic allotrope of oxygen) and nitrogen oxide. Either can be toxic in sufficient concentrations. Ironically, people who have asthma and allergy are most prone to the adverse effects. For example, increasing ozone concentration can increase the risk of asthma attacks. Due to the below average performance and potential health risks, Consumer Reports have advised against using ozone generators.
In September, 2007, the California Air Resources Board announced a ban of in-home ozone generators. This law, which will take effect in 2009, will require testing and certification of all types of air purifiers to verify that they don't generate too much ozone.
Ionic air purifiers
Ionic air purifiers use an electrically charged plate to produce negative gas ions that particulate matter sticks to (in an effect similar to static electricity).
Many ionizers are sold as air purifiers, but in this regard they are very inefficient. They will clean the air to a small degree, by charging dust and smoke particles which will then be attracted to a neutral or positively charged surface. Heavier combined particles may precipitate (fall) out of the air should two smaller particles of different charge clump together.
Benefits of negative ions
Cedars-Sinai has a page last reviewed 03-15-2006 which discusses negatively ionized air as an alternative treatment for certain conditions.
The Geophysical Institute of the University of Alaska Fairbanks published an article September 26 1981 which discusses the beneficial role of negative ions and the positive ion fields created by CRT (cathode ray tube) computer monitors.
[Natural Depression Treatment] has published an article with reference to Tom G., Poole M. F., Galla J., Berrier J.(1981).
(The influence of negative air ions on human performance and mood. Human Factors, Vol 23(5), Oct 1981. pp. 633-636), wherein it is being discussed how negative ions may be used also as a natural remedy to depression and mood improvement.
Ions vs. Ozone
Ionizers should not be confused with ozone generators, even though both devices operate in a similar way. Ionizers use an electro statically charged plate to produce positively or negatively charged gas ions that particulate matter sticks to (in an effect similar to static electricity).
Ozone generators are optimized to attract an extra oxygen ion to an O2 molecule, using either a corona discharge tube or UV light. Even the best ionizers will produce a small amount of ozone, and ozone generators will produce gaseous ions of molecules other than ozone (unless fed by pure oxygen, not air).
Ozone is claimed by some alternative medicine to be relatively harmless to humans, but this is a demonstrable fallacy. Ozone is a highly toxic and extremely reactive gas. A higher daily average than 0.1 ppm (0.2 mg/m³) is not recommended and can damage the lungs and olfactory bulb cells directly.
At high concentrations, ozone can also be toxic to air-borne bacteria, and may destroy or kill these sometimes infectious organisms. However, the needed concentrations are toxic enough to man and animal that the FDA explicitly demands ozone therapy not be used as medical treatment, and has taken action against businesses that fail to comply with this regulation.
Conclusions
Whether in its pure form or mixed with other chemicals, ozone can be harmful to health.
When inhaled, ozone can damage the lungs. Relatively low amounts of ozone can cause chest pain, coughing, shortness of breath and, throat irritation. It may also worsen chronic respiratory diseases such as asthma as well as compromise the ability of the body to fight respiratory infections.
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