If you are looking for an air purifier to help with allergies, you are already off to a good start. Whether it is pollen, pet dander, dust mites, or any other airborne allergy, an air purifier is your best defense against allergy symptoms. Plus an air purifier helps fight other types of indoor air pollution for better respiratory health. Let’s look at all the factors you need to consider when buying an air purifier for your allergies.
How An Air Purifier Works
Cleaning the air seems like a simple enough concept, but there are actually a few different ways to accomplish the task. For the sake of simplicity we’re going to focus on residential air purification methods (commercial air purifiers can get complicated).
Most portable air purifiers use a motorized fan to draw air into the unit through one or more intake ducts. The air is pulled through a section of the unit housing an air cleaning device (like a filter). The fan motor is typically located behind the filter media in order to protect it from dust and dirt. The fan motor is also cooled by the passing air. The fan itself is designed to move air efficiently with as little noise as possible.
The air filter is designed to fit the air filter chamber precisely to minimize air bypass. High-quality air purifiers use a gasket to seal the air filter to the air filter chamber, thus preventing any air from bypassing the filter. The cleaned air is then sent back out into the room via an exit duct.
Air Purifying Methods
For an air purifier to work it has to move air through some sort of air cleaning material or device. These are the most common air purifying methods.
Mechanical
This is the most basic form of airborne particle filtration. A filter made up of layered fibers (paper, fiberglass, plastic, etc.) is used to catch particles as they travel through the media. The particles may be caught by inertia, interception, impaction, even electrostatic (think static cling) methods.
Mechanical filters are graded on the Minimum Efficiency Reporting Value (MERV) scale based on their ability to capture particles. MERV rating ranges from 1-16 with lower numbers being least capable and higher numbers being the most effective at capturing small particles. Regardless of what you read online, there is no MERV rating higher than 16 (MERV 17 through MERV 20 are not officially recognized by any standard system). The HEPA filter rating is used to denote the ability to remove 99.97% of particles that measure 0.3 microns in diameter.
Mechanical filters (including HEPA filters and UltraHEPA filters) are limited in that they can only remove physical particles from the air stream. A mechanical filter alone cannot remove chemicals or odors caused by VOCs.
Adsorption
This method uses a material such as activated carbon to remove chemicals from the air. Activated charcoal has an immense amount of surface area (like a sponge) for its relative size. Chemicals like volatile organic compounds (VOCs) stick to the surface of the activated carbon as the air passes by. An activated carbon filter eventually becomes saturated and can no longer capture chemicals even though air may continue to pass through it. Activated carbon filters must be replaced and cannot be cleaned.
UV Light
This is not to be confused with the old “black light” found in many dorm rooms. This method uses short-wave ultraviolet (UV-C) light from a special bulb or LED to render microorganisms inactive. It disrupts the DNA/RNA so that the microorganisms can’t reproduce. The UV-C light is housed inside the air purifier and shielded so that the light cannot be seen from outside. Air passes through the UV-C light chamber and any airborne microorganisms are exposed to the light. For this method to be effective the microorganisms must be exposed to the UV-C light long enough to be affected.
Photochemical oxidation (PCO) is a technology that uses UV light along with a special catalyst to break down airborne pollutants. An offshoot technology called photoelectrochemical oxidation (PECO) has also been used for air purification.
Ion Emitting
This method uses a high-voltage ion generator (ionizer) to typically generate negative ions. These negative ions give airborne particles (dust, pollen, smoke, etc.) a negative charge. The negatively charged particles are attracted to nearby surfaces instead of staying airborne. Ozone may be created as a byproduct of the ion generation used by ionizer-type electronic air cleaners. These types of air cleaners do not work as well in areas of high humidity.
Ozone Emitting
In some situations an ozone generator is used to purify air, but only when carefully handled. Ozone can be used to remove smells and kill microorganisms. Ozone-generating air cleaners cannot be used in spaces occupied by living things. The air purifier creates ozone using either high-voltage or UV light. Ozone itself is a pollutant and can trigger breathing issues. Unfortunately ozone purification can also create harmful compounds as a byproduct.
Combining Air Cleaning Methods
It is not uncommon for these different methods to be combined (such as a mechanical filter with an activated carbon layer) to provide more comprehensive air cleaning ability. Having multiple air purifying methods can help produce cleaner air without needing another machine. Don’t forget that simple cleaning methods like regular vacuuming or using a dust mop can also help remove particles before they become airborne.
Verifying Cleaner Air
There is an industry recognized test called the Clean Air Delivery Rate (CADR) created by the Association of Home Appliance Manufacturers (AHAM). CADR is the measure of how much clean air an air purifier can deliver in cubic feet per minute. The larger the number, the more air is being cleaned. For example the Intellipure Compact has a PM2.5 Clean Air Delivery Rate (CADR) of 137.5 cubic feet per minute at its highest fan speed setting (Turbo). For an air filter to earn a HEPA certification it must conform to the strict HEPA standard. A HEPA filter must remove at least 99.97% of 0.3 micron particles in a single pass.
Benefits of Cleaner Air
If your local outdoor air quality indicators are in the red, more than likely your indoor air quality is at risk too. Having your own indoor air purifier helps relieve allergies, reduce asthma triggers, reduce airborne illnesses, improve sleep quality, even reduce airborne pollutants. Regardless of how an air purifier works, having cleaner air is always a good choice.
Choosing An Air Purifier By Room Size
Sizing an air purifier for space where it will be used is extremely important for allergy sufferers. Allergy-free air can make a big difference and is likely the main reason for buying an air purifier in the first place.
How Air Purifiers Are Rated
The main problem people face is using an air purifier that is too small for the space. Air purifiers are rated by how much air they can clean in a given time, known as the Clean Air Delivery Rate (CADR). The Association of Home Appliance Manufacturers (AHAM) offers an extremely comprehensive set of regulations around air purifier CADR testing and certification.
CADR testing is done using a special sealed test chamber to keep out any external contaminants. A controlled amount of test particles are added to the chamber and mixed into the air. The air purifier is placed in the chamber and operated at its maximum speed setting. Different particle sensor locations around the chamber monitor how long it takes the air purifier to clear the air.
It is important to know how often the air in the room is being filtered, which is known as the air changes per hour (ACH). The higher the ACH, the more often the air is being cleaned and the cleaner the air will be. Ideally the ACH for an air purifier being used in a space should be at least four. That means the air in the room is cleaned four times each hour.
The volume of air an air purifier can clean in an hour (CADR) is divided by the room volume (in cubic feet). If an air purifier with a CADR of 100 cubic feet per minute is placed in a 10'x 10'x8 room (800 cubic feet) the ACH will be 7.5, which is great. If that same air purifier is put in a 20’x40’x8’ room (6,400 cubic feet) the ACH will be 0.9, which is not great.
Picking An Air Purifier By Room Size
Choose an air purifier based on the room it will be used to clean. For reference here’s a few average space sizes where air purifiers are used and the necessary minimum CADR need to maintain four air changes per hour:
- Average bedroom - 132 square feet (1,056 cubic feet), minimum CADR 70.4 CFM
- Average living room - 216 square feet (1,728 cubic feet), minimum CADR 115.2 CFM
- Average kitchen - 150 square feet (1,200 cubic feet), minimum CADR 80 CFM
- Average apartment size - 900 square feet (7,200 cubic feet), minimum CADR 480 CFM
- Average single family home size - 2,000 square feet (16,000 cubic feet), minimum CADR 1,067 CFM
It is worth the time to measure (even just a rough estimate) the size of the room you plan to place the air purifier. For larger spaces (like an entire home) it is possible to use portable multiple air purifiers that add up to the desired CADR, or a single whole-home air purifier that is added to the existing HVAC system. If you match the room size to the air purifier CADR you will make a wise choice.
Air Purifiers for Specific Needs
There are certain situations where a specific airborne pollutant needs to be removed. Here’s a few things to consider when looking for an air purifier to combat a specific issue.
Pet Allergies
Almost every pet leaves something behind in the air where they live. An air purifier for pets will need to remove both particles and VOCs (odors). For easier maintenance choose an air purifier that has a pre-filter that can be cleaned (usually with a vacuum cleaner) multiple times before replacement, as pet hair tends to build up quickly.
Pet hair alone can be easily captured by almost any filter down to a MERV 1, but other pet dander is another story. Pet dander can fracture down to extremely tiny sizes. Pet dander is considered both a PM2.5 and PM10 airborne particle due to the potential size range. That’s why it is important to use an air purifier that is rated at or equal to HEPA performance (99.97% capture of 0.3 micron particles in a single pass).
Removing pet smells requires a VOC filter equipped with activated charcoal or similar material. Ideally the VOC filter should be replaceable separate from the main filter, as it will likely become saturated with pet smells faster than the main filter reaches end of service. Stay away from ozone-generating air cleaners to remove pet smells because ozone itself is a harmful pollutant.
Wildfire Smoke
You don’t have to live right next to where a fire is burning to be affected by the smoke. Wildfire smoke can travel hundreds of miles through the atmosphere. The soot can be extremely fine, quickly clogging up not only HEPA filters but anything else that draws air through itself (like computers, refrigerators, even video game consoles). Smoke can also carry harmful chemicals, especially if the fire is consuming man-made structures (homes, businesses). A VOC filter is highly recommended to remove harmful airborne chemicals. For wildfire smoke an air purifier will likely need to have the filters changed out more often, so ease of maintenance is key. It is also important to stock up on filters before wildfire season begins in your area.
Pollen
Seasonal pollen allergies affect a large number of people every year. Pollen is quite adept at making its way indoors where it can cause havoc with your sinuses and even your sleep. Pollen comes in a wide variety of sizes which is why an air purifier needs to be able to capture everything from large particles to the very small. For pollen the main goal is particle removal, so make sure the main air purifier filter can capture particles in the PM10 range (10 microns). Pollen is relentless at peak times so make sure the air purifier CADR rating is sized for the room. Once pollen season is over make sure to change your air purifier filters.
Best Air Purifiers for Allergies
Picking the best air purifier for allergies doesn’t have to be difficult. The Intellipure Compact removes up to 99.97% of allergens, mold, and viruses from the air. Intellipure’s proprietary Disinfecting Filtration System (DFS) utilizes electronically enhanced filter technology to achieve particulate capture. When running at maximum fan speed the Compact Clean Air Delivery Rate (CADR rating) was tested for various particles:
Smoke - 129.7 cubic feet per minute
Dust - 145.7 cubic feet per minute
Pollen - 158.8 cubic feet per minute
PM2.5 - 137.5 cubic feet per minute
If airborne allergies like pet dander, pollen, dust mites and more keep you reaching for the antihistamines, a high-quality air purifier may be a better solution. The Compact also features a pre-filter that removes volatile organic compounds (VOCs) such as harmful chemicals and nasty odors.
Setting Up & Maintaining Your Air Purifier
Once you’ve selected an air purifier and brought it home it is time to put it to work.
Unboxing Your Air Purifier
Start by reading the instruction manual to get familiar with the unit. It should cover things like if your unit has a charcoal filter, pre-filter cleaning, as well as filter replacement in general. Remove any packing material from the air purifier. It is not uncommon for there to be packing material inside the unit to prevent any damage during shipping. If the filter is wrapped in plastic, remove it. Recycle or dispose of all air purifier packaging in the appropriate manner.
Setting Up Your Air Purifier
Pick a place in the room that is near an available electrical outlet (it is best to not use an extension cord). Place the air purifier near the middle of the room if possible for the best air circulation. If the center of the room isn’t available, place the air purifier in an area that is unobstructed to allow air to flow around it. Avoid placing it directly against a wall or in a corner. Keep the air purifier 12” away from any walls, furniture, or other obstructions.
Running Your Air Purifier
Turn on the air purifier and test that it works on all fan speeds. If everything is working fine choose a fan speed that best suits how often you want the air in the room circulated. Refer to the CADR rating of the air purifier to get an idea how often the air in the room will be cleaned on the highest fan speed, then adjust the fan speed accordingly. You may choose to increase or decrease the fan speed based on indoor activities (such as cooking, house cleaning,or having a large number of guests).
Maintaining Your Air Purifier
At some point you will need to replace the main HEPA filter (or HEPA equivalent filter). It is wise to have a new filter on hand beforehand to minimize any air purifier downtime. If you have a washable pre-filter refer back to the owner’s manual and follow the instructions exactly. To help keep track of when you change the filter use a permanent marker to write the current date on the side of the new filter (not on the filter media, the outside frame). Whenever you maintain your air purifier take a moment to wipe it down with a microfiber cloth to remove any dust from the outside. If there is any dust or hair built up on the intake grate remove it with a handheld vacuum cleaner brush attachment.
