Air Cleaner Effectiveness

Natural Healthy Home Cleaning Tips
Air Cleaner Effectiveness

According to the EPA:
Three strategies (in order of effectiveness) that may be used to reduce indoor air pollutants are source control, ventilation, and air cleaning. Air cleaning may achieve an additional reduction in the levels of certain pollutants when source control and ventilation do not result in acceptable pollutant concentrations. However, air cleaning alone cannot be expected to adequately remove all of the pollutants present in the typical indoor air environment.

cleaners are usually classified by the method employed for removing particles of various sizes from the air. There are three general types of air cleaners on the market: mechanical filters, electronic air cleaners, and ion generators. Hybrid units, using two or more of these removal methods, are also available. Air cleaners may be in-duct units (installed in the central heating and/or air-conditioning system) or stand-alone portable units.

The effectiveness of air cleaners in removing pollutants from the air is a function of both the efficiency of the device itself (e.g., the percentage of the pollutant removed as it goes through the device) and the amount of air handled by the device. A product of these two factors (for a given pollutant) is expressed as the unit's dean air delivery rate (CADR).

Portable air cleaners vary in size and effectiveness in pollutant reduction capabilities. They range from relatively ineffective table-top units to larger, more powerful console units. In general, units containing either electrostatic precipitators, negative ion generators, or pleated filters, and hybrid units containing combinations of these mechanisms, are more effective than flat filter units in removing tobacco smoke particles. Effectiveness within these classes varies widely, however. For removal of larger dust particles, negative ion generators, without additional particle capture mechanisms (e.g., filters), may perform poorly.

in indoor air may be divided, for convenience, into three groups: particles, gaseous pollutants, and radon and its progeny. Some air cleaners, under the right conditions, can effectively remove small particles which are suspended in air. However, controversy exists as to the efficacy of air cleaners in removing larger particles such as pollen and house dust allergens, which rapidly settle from indoor air. In assessing the potential efficacy of an air cleaner in removing allergens, one should consider the relative contribution of airborne to surface concentrations of the allergens, particularly in the case of pollen and house dust allergens where natural settling may be so rapid that air cleaners contribute little additional effect. Animal dander may settle more slowly although, again, the surface reservoir far exceeds the amount in the air. Furthermore, control of the sources of allergens and, where allergens do not originate outdoors, ventilation should be stressed as the primary means of reducing allergic reactions.

Some of the air cleaners containing sorbents may also remove some of the gaseous pollutants in indoor air. However, no air-cleaning systems are expected to totally eliminate all hazards from gaseous pollutants and these systems may have a limited lifetime before replacement is necessary. In addition, air cleaning may not be effective in reducing the risks of lung cancer due to radon.

In choosing an air cleaner, several factors should be considered. These include:

The potential effectiveness of the device under the conditions it will be used.
The need for routine maintenance, including cleaning and replacement of filters and sorbents.
The estimated capital and maintenance cost.
The installation requirements (e.g., power, access).
The manufacturer's recommended operating procedures.
The possible production or redispersal of pollutants, such as ozone, particles, formaldehyde, and trapped gaseous pollutants.
The inability of air cleaners designed for particle removal to control gases and some odors, such as those from tobacco smoke.
Possible health effects from charged particles produced by ion generators.
Possible soiling of surfaces by charged particles produced by ion generators.
The noise level at the air flow rates that will be used.

Finally, one Federal standard, addressing only high efficiency air filters, and two standards provided by independent standard-setting trade associations outside the Federal government may be useful as guidelines in choosing an air cleaner for reduction of particles in indoor air. For induct systems, the atmospheric dust spot test of ASHRAE Standard 52-76 and the DOP method in Military Standard 282 may be used, respectively, to estimate the performance of medium and high efficiency air cleaners. For portable air cleaning systems, ANSI/AHAM AC-1-1988 may be useful in estimating the effectiveness of the units. Similar standards are not currently available to compare the performance of air cleaners in removing gaseous pollutants or radon and its progeny.

Air Purifiers and Air Filters Can Help The Health of Alergy and Asthma Sufferers
By S.A. Smith

Indoor air pollution in the form of dander, dust and pollen particulate matter can be a real irritant for suffers of asthma, allergies and other respiratory conditions. In addition to removal of all direct irritant sources and minimizing the irritant containment materials in your house, you should also consider the indoor ventilation and filtration system of home.

Environmental control is the key to reducing exposure to indoor and outdoor allergens. Keeping a clean house free of dust, dander, smoke, pollen, and other airborne particulate matters will help to reduce the irritation and effect on family members with respiratory difficulties. Air cleaners, filters and hepa filters can play a role in helping to control or reduce the exposure to indoor and outdoor allergens.

Several health authorities have recognized that certain types of air filtration systems can be beneficial in reducing the amount of airborne particulates in a room. The American lung association recommends using a hepa air filter purifier for the bedrooms of asthma suffers. The Mayo clinic recommends an air particle filter for household ventilation systems. Ionic filters and hepa filters have been endorsed or recognized by the Asthma and allergy foundation of America (AAFA) and the British Allergy Foundation seal of approval.

Selecting the wrong type of filtration system could exacerbate the problem by agitating and circulating the existing particulate matter throughout your house, so it is important to do your research thoroughly. Ionic air filters do not create high airflow patterns to clean the air and simply rely on negative ion attraction to collect the airborne particulate matter. They have demonstrates to have decent capture rate of airborne allergens and irritants like pollen, dander, tobacco smoke and dust and can help improve the quality of your indoor air environment.

Air filtration systems should not be considered as a solution for any respiratory condition, nor as a reason to ignore sound medical advice and guidance about the removal of irritant sources and allergen habitats from your household. They are also not a substitute for thorough and regular cleaning of your household environment. Selecting the right air purifier system can help complement and enhance your efforts to reducing airborne particulate matters, as well as maintain a healthier indoor breathing environment.

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