Air Purifier Information & Buying Tips

Air Purifier Categories

How Much Air Purification Do I Need?

Air Purifiers: What is ACH?

Is HEPA filtration enough for my allergies symptoms?

Air Purifiers and Power Consumption

The 20 Most Common Household Contaminations

Are Air Filters Good in Preventing Asthma Attacks?

 

Air Purifier Categories

 

A simple way to categorize air purifier systems is by dividing them into three major groups: Small, Medium and Large. Small air purifiers are designed for spaces up to around 200 sq. ft., like a small apartment or bedroom. These purifiers range from small table-top versions to small boxy units about the size of a carry-on luggage. These have lower Clean Air Delivery Rate ratings because of the lower volume of air that is pushed through by their smaller fans and smaller filter area. The cost of these units can range from about $30 for a retail-store model to about $299 on the top end for a high efficient, compact unit, like the Austin Air HM200. or the Blueair 203. Buyers of this category should beware that the department store brands in many cases only produce about 10% of their advertised efficiency.  

Medium air purifiers will successfully clean the air in about 200-350 sq. ft. For many regular sized bedrooms, these purifiers will provide more than enough "Air Changes per Hour" and cleaning efficiency for these spaces. Because high fan speeds are not usually needed for this category of purifier, they can operate more quietly and efficiently than their smaller counterparts. Most units in this category will have very similar features, so the important thing is to look at is the long-term cost operation (filter cost) and the warranty. You can expect to pay $200 on the very low end to $599 on the high end. The Blueair 303, 403 and the 450E fall in this category and are some of the most efficient units on the market. Beware of "bargain" purifiers that advertise this square footage capability, costing less than $200. More than likely these units are not dependable and do not perform as advertised.  

Large air purifiers are considered large for domestic-use standards, up to 900 sq. ft. These units will handle several rooms at a time, or can offer the sensitive person extra clean air in normal size living spaces. Initial cost of these purifiers are between $600 and $1000, and are therefore are an important investment decision. These units often offer multiple stage filtration, like particle filtration with True HEPA and odor abatement with activated carbon filters. While medium air purifiers share many of the same features, large purifiers utilize many different kinds of technologies, such as UV, TiO2, Ionic charge, Electrostatic charge, carbon blends and pre-filters. Not everyone needs these technologies, and the specific unit you need depends on the conditions that affect your allergy symptoms. See our article "How much Air Purification Do I Need?" for more info.

 

How Much Air Purification Do I Need?

How much air purification do I need? Are all air purifier technologies the same? How do I know which one is right for me? We have broken down the three major levels of purification as a guideline to discover what kind of air purifier technologies would be right for you. Just because an air purifier promises to provide technologies for all three levels of purification doesn't mean that you need it. Remember to look for a quality air purifier in the category that most affects your allergy symptoms.

1. Clean:

This is the most basic level of air purification and applies to most people searching for ways to treat dust, animal dander and pollens in the air. Cleaning the air is most commonly accomplished through HEPA filtration, since it is effective, efficient and can be disposed of when the filter reaches saturation. Dust and other airborne particles can be treated with ion generators and ozone generators, but these tend to just charge the particles so that they cling to a surface that has to be washed by hand. In most cases, this would not be practical for someone with allergies to handle dirty collector plates. We recommend the IQAir HealthPro, IQAir HealthPro Compact, Blueair 603 with HEPA Silent, Airgle 750, Airpura H600, and the Austin HM400 for Stage 1 Cleaning.

2. Deodorize:

The next level of filtration is the removal of chemical gases, tobacco smoke and VOCs (Volatile Organic Compounds). The removal of these gases at the sub-micron level is done through activated carbon filtration. The IQAir HealthPro Plus comes with both superior HEPA filtration and the specially designed V5 Cell Carbon Filter. The Airgle 750, Blueair 650E with SmokeStop and the Austin HealthMate Plus come with activated carbon filters that work along with the standard HEPA filters. If chemical gases and aerosols are a major concern in environments such as paint shops, beauty salons, factories and hospitals, you'll want to check out the industrial-grade Airpura R600, C600, V600, P600 and the T600.

3. Sanitize:

The final stage is for the most sensitive person with weak immune systems. This stage eliminates microorganisms, bacterias and flu virus from indoor air. There are several popular technologies that treat these microorganisms, including Ultra Violet, Photocatalytic Oxidization (using TiO2 reflectors), Ozone Generators and Germicidal Filters. The Airpura P600 includes 5 technologies to treat all 3 stages of air purification. The Airpura UV600 is also equipped with a UV lamp for the elimination of bacterias and microorganisms.

 

 

Air Purifiers: What is ACH?

 

ACH refers to the Air Changes per Hour of an air purifier unit. ACH is the total number of times in one hour the entire volume of room air passes through the air cleaner. The more often the air passes through the filter, the more often it will be cleaned. If your room is smaller, obviously will take less time to clean than a larger room with the same air cleaner with a certain ACH. How do I know what ACH rating I need for my room? Most air purifiers will specify the total square footage that can be cleaned in one hour. If that maximum cleaning area is,say, 2000 sq. ft., then for most situations we need at least 4 changers per hour. So in this example, the air cleaner could effectively change the air four times each hour in an area of about 500 sq. ft. (larger than most rooms). See our product pages for specifications including ACH and many other details that will help you select the air purifier that's right for you.

 

Is HEPA Filtration Enough for Your Allergy Symptoms?

 

HEPA filters (High Efficiency Particulate Air Filter) work on the principle of impingement, or the use of media placed in the path of oncoming airborne particles and striking the particles as it flows by in an effort to stop it. The degree of effectiveness of this method depends on the amount of material contained in the media filter placed in the path of these oncoming airborne particles. Naturally, impingement type filters always have a built-in compromise between airflow and efficiency. The greater the efficiency of the filter, the lower the volume of air that is filtered. Some air purifiers, like the Blueair, have tried to solve this dilemma by placing the filter media in stages- from coarsest to finest, to help avoid clogging of the HEPA media. Impingement media that is considered "HEPA" will remove at least 99.97% of airborne particles down to 0.3 microns in diameter. For many people who suffer from occasional allergies to dust and pet dander, HEPA may be sufficient for removing those allergens from the air. There are, however, many categories of allergy triggers that may not fall in the range of capacity for the standard HEPA filter to remove them. Below is a chart of common airborne particulates:

 

The chart indicates, with bold line through the middle, the capacity of filtration of the standard HEPA filter. From the bold line to the right side are particulates 0.3 microns or greater. On the left side of the line are particulates that are smaller than 0.3 microns. These include fine household dust, fumes, gases, wood smoke, viruses and bacterias. For the filtration of these particulates, the air cleaner needs to be equipped with more than standard HEPA. In this sub-micron range of potential allergens, we need to look for a second type of filtration, and sometimes a third. For most household fumes from chemicals and cleaners, an activated carbon filter will sufficiently remove these odors. Carbon filters are also used to remove wood smoke or smoke produced by cook stoves. These filters are limited, however, when it comes to eliminating germs, viruses or other microorganisms. For this level of filtration, we need germicidal filters (as featured in the IQAir HealthPro Plus), UV germicidal lamp, Photocatalytic Oxidization, or Ozone Generators. These filters either treat the microorganisms with a chemical process or cause them to become inert through oxidation. Discovering what kind of filtration method is best for you begins by discovering what is triggering your allergy symptoms, removing them as best as possible on all surfaces, and then choosing the filter type that will handle the particulate size and type.

 

Air Purifiers and Power Consumption

 

For many reasons consumers are becoming much more conscientious of energy usage when it comes to household appliances, both large and small. One major reason is personal, to reduce their overall expenses and make their income stretch farther. Another would be more as a social obligation to reduce their carbon footprint on the environment.

 

This article is written to compare major types and brands of air purifiers to find the balance of cleaning efficiency and lowest possible power usage. As with central air and furnace systems, there is certainly a challenge in moving a house full of air with the least amount of energy. Some of the earliest types of ionic purifiers achieved impressively low power usage while claiming to zap impurities out of the air, both particulate and molecular. Not only were they found to produce unhealthy amounts of ozone, but they were also found to be ineffective at actually cleaning the air. This was partly because the air could not be moved through the unit, since it was not equipped with a fan. So much for a low-power air purifier!

 

Is it possible to marry the two objectives? Can a high quality HEPA-equipped purifier also use low amounts of energy to move the air necessary for the removal of dust, pollen, smoke or organic particles? In my search for such a purifier that meets these requirements, I found that many units that claim low power usage also sacrifice cleaning efficiency (poor CADR* ratings in comparison with other units). In addition, the comparison of air purifiers based on energy usage at the highest fan settings is not a fair method for discovering the intersect of effectiveness and energy use, because an air purifier rarely needs to be run on high speeds for any length of time.

 

One helpful resource I found was on the EnergyStar website that gave product comparisons with a specific column labeled as CADR/Watt, which is simply a number representing the amount of cleaning efficiency expressed in the CAD rating per watt of power used to circulate the air (and run any other electronic technologies for the cleaning process). Although dozens of models are not included in the database, it's easy to see that many manufacturers that claim “low power consumption” do not necessarily have a high CADR/Watt rating. The highest rated unit in this comparison is the Blueair ECO 10 with a score of 19.66, while most rank with a score of 3 or less. Keep in mind that units with a high score may be more air purification than you actually need, and in small, confined spaces the newer and safer ionic-type purifiers with low power consumption (as low as 12 watts) may be adequate. Moving up to medium to large spaces, these technologies lose their efficiency. For these areas, the objective would be to find a unit with a CADR as high as 400, like the Blueair or Airgle, and then narrow these models down by power usage.

 

* Clean Air Delivery Rate (CADR) is a measure of the appliance’s ability to reduce smoke, dust, and pollen particles in the 0.10 to 11 micron (μm) size range from the air. In ANSI/AHAM AC-1-2006, CADR is defined as “the rate of contaminant reduction in the test chamber when the unit is turned on, minus the rate of natural decay when the unit is not running, multiplied by the volume of the test chamber as measured in cubic feet.” The 1008 ft3 test chamber size is an integral part of the definition and is standardized in ANSI/AHAM AC-1-2006 to ensure that comparisons between units that have been evaluated using the standard are fairly made. This standardized room size chamber limits the maximum CADR measurement (or value) to 450 (pollen and smoke) and 400 (dust). These maximum CADR values were determined through analysis of the acceptable minimum number of available particles, an average background natural decay rate (from statistical study), the size of the chamber, and the available minimum experiment time.

 

The 20 Most Common Household Contaminants

 

As houses become more and more efficient, the indoor air we breathe may actually get worse due to the lack of circulation of fresh air from the outside. Below is a list of the 20 most common contaminants found in our indoor air.

1. Insulation- fiberglass particles are of greater concern than asbestos, which can still be found in older houses. Urethane can also be cause for concern.

2. Pressed wood in furniture and flooring- most are manufactures with formaldehyde, a harmful gas that contaminates indoor air.

3. Dry cleaning- can be a source of toxic toluenes and PERC.

4. Dust mites- the excreta and body parts of these organisms are a common allergen, particularly on mattresses.

5. Lead- sometimes found in older paints and plumbing pipes.

6. Aerosols in personal care products- a common source of organic gases, some of which are suspected carinogens.

7. Gas stove- can be a source of combustion by-products.

8. Household cleaning products- can contain harmful VOCs (volatile organic compounds).

9. Pesticides- are a source of extremely toxic chemicals that can be released into indoor air.

10. Smoke from fireplace or wood stove- open fireplaces can produce ash dust, carcinogenic tars and combustion by-products like carbon monoxide and nitrogen oxides.

11. Wall coverings- plasticized wallpapers can emit VOCs and wood paneling is often manufactured with formaldehyde.

12. Draperies- treated fabrics can contain formaldehyde and curtain folds collect dust.

13. Tobacco smoke- contains 43 carcinogens, is dangerous to nonsmokers from second-hand smoke, especially to children.

14. Carpets- often a source of formaldehyde, they harbor dust, dust mites, molds and animal dander.

15. Paints and solvents- these are sources of many volatile chemicals, which are easily vaporized.

16. Fuels- storage of gasoline, kerosene, and other fuels can release volatile chemicals into household air.

17. Pet dander- animal hair and skin flakes are a common source of allergens.

18. Auto exhaust- fumes can enter the home from the garage or nearby traffic flow. Carbon monoxide is the primary danger, and has a cumulative effect in the human system.

19. Radon- radon gas is a natural emission where uranium exists underground.

20. Radon carries radioactive particles that can be a dangerous cause of lung cancer. For protection against all of these contaminants, use an air purifier that treat all three stages of purification: particles, odors and chemicals. See our specific air purifier systems that fall under this category. Protect yourself against these common contaminants with a high quality air purifier from Air Purifier Central.

 

Are Air Filters Good in Preventing Asthma Attacks?

 

Asthma sufferers know better how hard it is to cope with imminence of an asthma attack each and every day. They know better how many things they have to sacrifice in order to be at least a little bit safe, the pleasure they are deprived of in order to avoid an attack and the precaution measures they have to take each and every time they want to go out. Yet, their home should be a place in which all people should feel good and comfortable. In order to make the house a proper environment for an asthmatic, it is absolutely necessary that you offer them a clear air to breathe, safe from any kind of allergens (such as dirt, pollen, mold or animal hair). You can do that by cleaning the house regularly, throwing away the wall to wall carpets, washing the fabric items every week and cleaning all the other surfaces as often as possible with cleaning products which are specifically designed for sensitive people.

Even though the above mentioned methods are quite effective in keeping allergens away, there are still particles of dust, mold or animal hair which can be left unnoticed or which remain in the air. These allergens can easily trigger an adverse reaction from an asthmatic. Thus, filtering the air periodically will be one of the necessary steps which have to be taken in order to make the house a safe environment for an asthmatic.

There are two ways in which you can keep the air from a room clean. The first one is to buy an air cleaner. Depending on how large the air cleaner is, it will filter the air from a room or the entire house. Also, the filters can be replaced or cleaned when they get dirty, so that the breathable air is as clean as possible. The other method through which you can obtain a clean air inside the house is to install an air filter inside the air conditioning or inside the source of heating. Choose a permanent electrostatic filter for a better filtration and run the air conditioning even when it is not very hot outside or even use it for warming the room. This way it will be able to filter more air and reserve all the allergens inside the filters.

So, if you have an asthmatic living in your house or you are suffering from asthma, make sure that the air you breathe inside the house is fresh, clean and safe all the time, by filtering it continuously.

from “Natural Asthma Remedies: The Expert Guide to Coping with Asthma” by Portia Casey, August 8, 2010 (pages 4-5) links added by Air Purifier Central