Portable Air Cleaners and Furnace or HVAC Filters in the Home EPA Particle Pollution and Your Health: 3.epa/airnow/particle/pm-color.pdf. Furnace
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2Portable Air Cleaners and Furnace or HVAC Filters in the Home Indoor air contains pollutants that can affect human health. Some of these pollutants come from outdoors, and others come from indoor sources and activities, such as cooking, cleaning, secondhand smoke, building materials, consumer products, and home furnishings. These indoor air pollutants can be particles or gases, including volatile organic compounds (VOCs). Common contaminants that can be found indoors include particulate matter (including PM2.5 [˜ne] and PM10 [coarse]), formaldehyde, mold, and pollen. Indoor air quality will vary from home to home and over the course of a day within a home. Since most people spend about 90% of their time indoors, mostly in their homes, much of their exposures to airborne pollutants will happen in the home.The most effective ways to improve your indoor air are to reduce or remove the sources of pollutants and to ventilate with clean outdoor air. In addition, research shows that ˜ltration can be an effective supplement to source control and ventilation. Using a portable air cleaner and/or upgrading the air ˜lter in your furnace or central heating, ventilation, and air-conditioning (HVAC) system can help to improve indoor air quality. Portable air cleaners, also known as air puri˜ers or air sanitizers, are designed to ˜lter the air in a single room or area. Central furnace or HVAC ˜lters are designed to ˜lter air throughout a home. Portable air cleaners and HVAC ˜lters can reduce indoor air pollution; however, they cannot remove all pollutants from the air.
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3Tips For Selecting a Portable Air Cleaner, Furnace Filter, or HVAC Filter When selecting a portable air cleaner, furnace ˜lter, or HVAC ˜lter, keep in mind: No air cleaner or ˜lter will eliminate all of the air pollutants in your home. Note that most ˜lters are designed to ˜lter either particles or gases. So in order to ˜lter both particles and gases, many air cleaners contain two ˜lters, one for particles and another for gases (in some cases including gases that have odors). Other air cleaners only have one ˜lter, usually for particles. In addition, some air cleaners or ˜lters are targeted to speci˜c types of gases or VOCs. Consult the speci˜c product packaging or labeling for more information.All ˜lters need regular replacement. If a ˜lter is dirty and overloaded, it won™t work well.PORTABLE AIR CLEANERS To ˜lter particles, choose a portable air cleaner that has a clean air delivery rate (CADR) that is large enough for the size of the room or area in which you will use it. The higher the CADR, the more particles the air cleaner can ˜lter and the larger the area it can serve. Most air cleaner packaging will tell you the largest size area or room it should be used in. Portable air cleaners often achieve a high CADR by using a high-ef˜ciency particulate air (HEPA) ˜lter. To ˜lter gases, choose a portable air cleaner with an activated carbon ˜lter or other ˜lter designed to remove gases. Note that there are no widely used performance rating systems for portable air cleaners or ˜lters designed to remove gases. The CADR rating system is for particles only. Activated carbon ˜lters can be effective, provided that there is a large amount of material used in the ˜lter. A portable air cleaner with a high CADR and an activated carbon ˜lter can ˜lter both particles and gases.Generally speaking, higher fan speeds and longer run times will increase the amount of air ˜ltered. An air cleaner will ˜lter less air if it is set at a lower speed. More air will pass through the ˜lter at higher fan speeds, so typically ˜ltration will be greater at higher fan speeds. Increasing the amount of time an air cleaner runs will also increase air ˜ltration.Portable Air Cleaner Portable Air Cleaner Sizing for Particle RemovalRoom area (square feet) 100200300400500600Minimum CADR (cfm)65130195260325390Note this chart is for estimation purposes. The CADRs are calculated based on an 8-foot ceiling. If you have higher ceilings, you may want to select a portable air cleaner with a higher CADR.
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4FURNACE AND HVAC SYSTEM FILTERS Furnace and HVAC ˜lters work to ˜lter the air only when the system is operating. In most cases, HVAC systems run only when heating or cooling is needed (usually less than 25% of the time during heating and cooling seasons). In order to get more ˜ltration, the system would have to run for longer periods. This may not be desirable or practical in many cases since longer run times increase electricity costs and may also result in less reliable humidity control during the cooling season. Furnace and HVAC ˜lters for homes are usually designed to ˜lter particles. If you decide to upgrade or use a higher ef˜ciency ˜lter, choose a ˜lter with at least a Minimum Ef˜ciency Reporting Value (MERV) 13 rating, or as high a rating as your system fan and ˜lter slot can accommodate. You may need to consult a professional HVAC technician to determine the highest ef˜ciency ˜lter that will work best for your system.Other devices that do not have ˜lters may also remove particles and gases. They usually ˜t inside the HVAC ductwork and are more common in large and commercial buildings. See the EPA technical document, Residential Air Cleaners, 3rd edition, for more information: www.epa.gov/indoor-air-quality-iaq/ residential-air-cleaners-second-edition-summary- available-information.EPA does not certify or recommend speci˜c brands or models of air ˜lters or portable air cleaners.Q&A: Air Cleaning and FiltrationDo portable air cleaners and furnace/HVAC ˜lters used in homes have the potential to improve my indoor air quality?Yes. Most portable air cleaners and furnace/HVAC ˜lters can ˜lter particles from the air. Some can ˜lter the small particles of greatest health concern (PM2.5). There are also air cleaners and ˜lters that can ˜lter both particles and gases. The longer the air cleaner runs, the more air it ˜lters. Note that it is always important to reduce or remove the sources of indoor air pollutants and to ventilate with clean outdoor air. Filtration does not replace the need to control pollutants and ventilate.Can portable air cleaners and furnace/HVAC ˜lters potentially have a positive impact on health? Possibly. Several studies using portable HEPA air cleaners have demonstrated small improvements in cardiovascular and respiratory health. The improvements are typically small and not always noticeable to the individual, although they may be measureable by health professionals.For more information on particles and health, see: Ł EPA Indoor Particulate Matter: www.epa.gov/indoor-air-quality-iaq/indoor-particulate-matter Ł EPA Particle Pollution and Your Health: www3.epa.gov/airnow/particle/pm-color.pdf Furnace Filter Furnace or HVAC ˜lterŠ Select a ˜lter rated at least MERV 13 or as high as your system will accommodate.
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5Can portable air cleaners and furnace/HVAC ˜lters reduce allergy or asthma symptoms? Possibly. Multiple studies with portable HEPA air cleaners have found improvements in one or more allergy and/or asthma symptom(s). The studies do not always show major improvements, and they do not show improvements in all symptoms. Can portable air cleaners and furnace/HVAC ˜lters solve mold problems? No. Portable air cleaners and furnace/HVAC ˜lters do not address the cause of mold and musty odors. Mold is caused by a water or moisture problem in the building that allows the mold to grow. To solve a mold problem, get rid of the source of the moisture and clean up the mold. Portable air cleaners and furnace/HVAC ˜lters may remove some of the particles generated by mold. In some cases, they may also help reduce odors, but they will not resolve a mold and moisture problem.Note: Avoid portable air cleaners and furnace/HVAC ˜lters that intentionally produce ozone. Ozone is a lung irritant. Note that in some cases, air cleaners that contain electrostatic precipitators, ionizers, UV lights without adequate lamp coatings, and plasma air cleaners may have the potential to emit ozone. Both the California Air Resources Board and the Association of Home Appliance Manufacturers maintain lists of air cleaners that have been tested and shown to emit little or no ozone.Q&A: Portable Air CleanersMost portable air cleaners have a CADR rating. What does that mean?Most portable air cleaners are rated according to their clean air delivery rate (CADR). This number is intended to help consumers select an air cleaner based on the size of the area it will be placed in. The higher the CADR, the more particles the air cleaner will remove and the larger the area it can serve. The rating is typically measured at the air cleaner™s highest speed. How do I choose a portable air cleaner that will remove the small particles of greatest health concern (PM2.5) effectively?Some air cleaner packaging will indicate CADRs for removing three speci˜c types of pollutants: tobacco smoke, dust, and pollen. These pollutants are used as examples to represent small-, medium-, and large-sized particles, respectively. To remove small particles, choose a portable air cleaner that has a high CADR for tobacco smoke, which represents the smallest particles. The CADR should be large enough for the size of the room or area you will use it in.How do I calculate the size of the room or area in order to pick the right air cleaner?Multiply the length and width of the area in which you intend to operate the air cleaner. The result will provide you with the size of the room or area in square feet. Compare this to the maximum recommended room size on the product packaging. If you have an open ˚oor plan, you should consider the entire space that the air cleaner would serve. If you have high ceilings (above 8 feet), you should consider using an air cleaner that is sized for a larger area. If you have an area that is larger than any available product will serve, you could consider using multiple air cleaners.
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6How do I choose a portable air cleaner that can remove volatile organic compounds (VOCs)?Choose a portable air cleaner with an activated carbon ˜lter or other absorbent ˜lter designed to remove gases. They can be effective when there is a large amount of material used in the ˜lter (the thicker the better). Research has not yet shown that other technologies such as plasma, photocatalytic oxidation, or ultraviolet (UV) light can remove gases effectively in portable residential air cleaners.Do portable air cleaners have noise ratings?Noise ratings are reported for some portable air cleaners. The rating may be shown on the product packaging. Noise levels depend in part on the fan speed setting. If noise might prevent you from running the unit, you might consider an air cleaner that has a low published noise rating. For reference, a noise rating around 50 decibels (dB) is roughly the operating noise of a modern refrigerator. Where should I put a portable air cleaner?Consider placing the unit in the room(s) you spend the most time in. Many units are designed to be placed on the ˚oor, although some are designed for tabletops. Either way, make sure the air˚ow is not obstructed. Keep air cleaners away from curtains and anything that might block air˚ow. If the air cleaner causes an uncomfortable draft, then redirect the air˚ow away from you.What does it mean if a portable air cleaner has the EPA™s ENERGY STAR ® label?Some portable air cleaners sold in the consumer market are ENERGY STAR quali˜ed. The ENERGY STAR label means that it meets strict energy ef˜ciency guidelines set by EPA. The label does not refer to its air-cleaning effectiveness in any way. Q&A: Heating, Ventilation, and Air-Conditioning (HVAC) System Filters and Furnace FiltersHow are HVAC/furnace ˜lters rated? There are several commonly used ˜lter rating methods. These include the Minimum Ef˜ciency Reporting Value (MERV), Filter Performance Rating (FPR), Microparticle Performance Rating (MPR), and others. MERV is based on a national consensus standard. The FPR and MPR rating methods are proprietary. For all rating methods, the higher the ˜lter rating, the higher the removal ef˜ciency for most particle sizes. How do I choose an HVAC/furnace ˜lter that will be most effective at removing small particles of greatest health concern (PM2.5)?Use the highest-rated ˜lter that your system fan and ˜lter slot can accommodate. Filters with a MERV of 13 and above are required to demonstrate at least 50% removal ef˜ciency for the smallest particles tested.This is an example of a label from a portable air cleaner. Used with permission from the Associa -tion of Homes Appliance Manufacturers (AHAM).
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