Unlike sight or hearing, smell isn’t a sense we rely on in daily life. However, something with a truly foul stench can feel like a swift kick to the face.  Want some examples?  Read on…

1. Who Me?

During World War II, the Allied Forces created Who Me – one of the most nefarious chemical weapons.  Its purpose: to make the target smell like feces.  The goal: to spray Who Me on German officers, thus embarrassing the Sheppard’s and demoralizing the sheep. Unfortunately, the plan didn’t work. After two weeks, the project was decommissioned because the Allied moles couldn’t avoid smelling just as bad as the targets, thus incriminating themselves.

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2. Ethyl Mercaptan (ethanethiol)

Ethyl Mercaptan smells like leeks…except much, much worse.  Used in propane to give the odorless fuel a distinct smell, 1 part of Ethyl Mercaptan can be detected – without instrumentation – in 2.8 billion parts of air.  It even has a claim to fame, being ranked as the Guinness Book of World Record’s smelliest substance.

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3. US Government Standard Bathroom Malador

U.S. Government Standard Bathroom Malodor is what nightmares are made of.  One whiff activates your fight or flight response, making your heart beat like a bass drum and your stomach do back flips.  During testing, volunteers would scream in horror and swear at the experimenters. This stuff makes rotten eggs seem like eau de toilette. And strangely, U.S. Government Standard Bathroom Malodor is essentially safe… even though it smells like Death smeared in feces and wrapped in a dead carcass.

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4. Butyl seleno-mercaptan (C4H9SeH)

Butyl seleno-mercaptan is the core molecule in a skunk’s spray, making it the bane of men and dogs alike.  Despite its foul stench, it has given mankind one benefit; skunk sprayings have fueled the sale of tomato soup for decades.

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5. Cadaverine

Cadaverine smells like Death…. literally.  As living flesh decays, amino acids interact and create Cadaverine.  When smelled, most men get a feeling of nausea and repulsion.

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6. Skatole

Here’s a strange fact:  small amounts of skatole is used to flavor vanilla ice cream.  But when it’s not being blended into dairy products, skatole is known for giving human feces part of its odor.  As the easiest smell for mankind to notice (our nostrils are particularly sensitive to skatole), we know when we’re close to stepping/sitting/sleeping in crap… and can better avoid it. Unless it’s hot out and we’ve decided to, you know, eat it.

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7. Butyric acid

The smell of vomit makes most people nauseas – and butyric acid is to blame.  The compound starts to tickle the human nostril at concentrations as low as 10 parts per million.  Other fragrant sources include rancid butter, foot sweat and certain stinky cheeses.

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8. Dibutyl Telluride

Deals on Air Purifiers:

Dibutyl Telluride has a bit of legend wafting from it.  Story has it that a German chemist, lost in thought, dropped a vile of Dibutyl Tellurid onto the train’s floor.  The vile smashed, releasing a smell that sent every passenger running for the door.  Weeks later, the stench was still so heavy in the train car (despite decontamination attempts) that the car had to be scrapped.

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9. Pyridine

Pyridine is colorless, but its stench is quite colorful.  Made from a concoction of bone oil (or coal tar) and various naturally occurring chemical compounds (alkaloids), pyridine has a smell you won’t easily forget.  Ever.

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10. Putrescine

Putrescine – picture a dead rat.  Then leave that rat to rot in your wall for a year.  Take that smell, and multiply it by 10 and you have an idea of what putrescine smells like.  In fact, the compound at the heart of putrescine is the same as that created by actual rotting flesh.

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11. Hydrogen selenide

Hydrogen Selenide smells like rotten eggs mixed with rotten radishes, and poisons you as it “clings” to the insides of your nostrils.  It is more toxic than Hydrogen Cyanide, and dulls your sense of smell… making it incredibly dangerous on top of being unpleasantly fragrant.

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12. HN3 – Mustard Gas

Mustard Gas doesn’t smell like mustard.  In reality, Mustard Gas induces fear and hysteria in those unlucky enough to encounter it.  Having no antidote, Mustard Gas caused more deaths during World War I than any other chemical weapon despite being less toxic than nerve gas.

13. Trimethylamine oxide,

This chemical is found more commonly in ocean sea life and is the reason that cod starts smell faster than river caught catfish.  This scent is caused by the breakdown in bacteria combined with the fish enzymes. If you ever smelt a week old fish you know how bad this can stink!

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14. Ammonia

Ammonia is 1 part Nitrogen, 3 parts Hydrogen and all parts repugnant.  Some of the more pleasant liquids with traces of ammonia include concentrated cleaning products, cat piss and human sweat.

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15. Isovaleric Acid

Isovaleric acid has an identity crisis.  On the one hand, the acid gives off at athletic foot smell and makes the body stink of B.O. On the other hand, one of isovaleric acid’s compounds (esters) is used in perfumes due to its fragrant scent.  Let’s just hope you catch it on one of its “up” days.

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Several home air purifier manufacturers have started including an ultraviolet (UV) lamp in their air purifiers. The reason for a UV lamp is that ultraviolet light in sufficient doses kills certain harmful microorganisms like viruses and bacteria. The people who are most at risk from airborne harmful microorganisms are very old people and very young people. That’s why air purifiers with UV stages are often seen in nursing homes and in child care centers and pediatrician offices.

Ultraviolet light is invisible to the human eye. The wavelength of UV light is shorter than the shortest-wavelength light we can see, which is violet. There are three types of UV light: UVA, the longest wavelength UV light; UVB, which is shorter in wavelength than UVA, and the shortest of all, UVC, which is the range of UV light that kills bacteria and viruses. Any type of UV light can damage the eyes and has been linked with the development of skin cancer, so it is very important to protect your eyes when checking on the UV lamp in an air purifier. Chances are that the light in the air purifier will not be direct enough or strong enough to damage eyes, but it is best to be safe.

The way UV light kills harmful microorganisms is that at it scrambles the organism’s DNA. The two wavelengths of UV light that are the most potent for killing bacteria and viruses are 185 nanometers and 265 nanometers. A UV lamp in an air purifier that claims to kill microorganisms should emit energy in one or both of these wavelengths.

The problem with UV lamps in home air purifiers is that the bulbs will still appear to work, because they light up in a violet color, even though they have stopped emitting light in the proper range to kill microorganisms. One way to avoid this problem is that when you put in a new UV bulb, you can write the date on the bottom of the air purifier, or put it on your calendar. The instruction manual that came with your air purifier will tell you how often to replace the bulbs, and you should write down this date or mark it on your calendar as well.

Even though UV rays are great for killing bacteria and viruses, they are not functional unless there is a filter of some sort (like a high efficiency particulate air, or HEPA filter) that filters air before it reaches the lamps. Without a particulate filtering system, there may be enough particulates to shade the microorganisms from the UV light. In most home air purifiers, the UV stage of the process comes last so that the air flowing through the UV light is as particulate free as possible.

Activated carbon is used in home air purifiers because, like air sponges, carbon filters trap airborne odors and gases. The reason it is called "activated" charcoal is that it’s been treated with oxygen. This opens up tiny pores between the carbon atoms and the pores trap the odors and gases. Carbon granules have a very convoluted surface, providing it with a large surface area to volume ratio, which makes carbon filters tops for trapping the gases that go through particulate filters first. But eventually, the pores become clogged with contaminants, and the filters must be replaced to function properly.

(Picture Caption) You an see in these closeups that activated carbon has a honeycomb formation. The odors and gases become trapped in the honeycomb pores.

Is One Activated Carbon Filter as Good as the Next?

No. Sometimes activated carbon is impregnated with special materials that make them more effective at trapping odors and gases. These specially enhanced activated carbon filters are able to remove the so-called volatile organic compounds, or VOCs from the air.

How Much Activated Carbon is Necessary?

In general, more carbon is better because as soon as all the pores in the surface of an activated carbon filter are plugged, the filter is no longer effective. Greater amounts of carbon will make a filter work better and last longer than a filter that only has a small amount of carbon. Filters with only small amounts of carbon can become useless in a matter of weeks. The best activated carbon filters have larger amounts of activated carbon. Some of them can last for over 18 months.

How Thick Should the Carbon Filter Be?

The thicker the better. The more time that the pollutant has contact with activated carbon, the better its chances of being trapped. Therefore, the thicker the layer of activated carbon the air flows through, the better the results.

What is the Difference Between Pads Impregnated with Carbon and Granular Activated Carbon?

Granular activated carbon is better. In fact, granulated activated carbon is better than a carbon pad filter of two inches thick or more. That’s because it has a greater surface area to volume ratio for trapping gases and odors than the impregnated pad filter. Pad filters with activated carbon will have to be changed far more frequently than activated carbon granule filters. The more contact the air has with the carbon, the greater the chances of the pollutants being trapped.

In summary, activated carbon is considered a "miracle filter" by many researchers. It has a great capacity for getting rid of unpleasant odors and volatile organic compounds, including those from pesticides. Activated carbon acts as an air sponge, trapping pollutants in its tiny pores. Activated carbon is the most preferred substance for removing numerous possibly hazardous or carcinogenic chemicals in the air. It’s likely that you will need to replace carbon filters every year or more depending on your air quality.

Allergy furnace filters can help to remove numerous common particles which make up typical indoor air pollution. They include pollen, dust mites, pet dander, pet hair, organic compounds, and chemicals from household products, including formaldehyde, chlorine, and toluene. Indoor air pollution can aggravate allergies and cause watering eyes, sneezing, and coughing.

Furnace filters are made of synthetic filters that combine the technologies of electrostatic air filtration and mechanical air filtration for optimum results. A gradient captures particles and minimizes air flow resistance simultaneously. As the air passes through, more particles are trapped. As the filter fills up with particulates, more and smaller particles are trapped, until the filter fills completely and must be changed (after a period of about three months).

Furnace filters are terrific for households with allergy and asthma sufferers. They are inexpensive and have proven to be very effective (over 90%) at catching dust, dander, and other larger particulates. The air filters come as pleated panels that are simply inserted into the filter opening of a household air conditioning unit. They do not use ionizers and they do not emit ozone in order to remove pollutants. There are some models of furnace filters that can be washed and reused, while others must be disposed of when they become clogged.

These filters consist of a simple (usually cardboard) frame and filter media. The frame holds the filter in place at the intake to the furnace or air conditioning system. Highly efficient furnace filters are made up of special synthetic filtration materials that provide both electrostatic and mechanical filtration for even better filtering results. These filters have a gradient layer that can capture particulates, but will not absorb moisture that could cause the growth of harmful molds and bacteria.

Picture: How a Furnace Filter Works

When you choose a furnace filter, learn what its minimum efficiency reporting value, or MERV is. The MERV is a rating of the filter’s ability of capturing particles sized between 0.3 and 10 microns in diameter. It is a helpful measure for comparing the performance of the different furnace filters you will choose from. The higher the MERV rating, the better the furnace filter is at capturing particles in this size range.

Furnace filters are easy to use, are very effective, and installation is very simple. You may not need any tools at all, unless you need a flat head screwdriver to turn the screws that hold the filter grill to your air intake in place. First, remove the old filter from the intake, being careful not to shake dust and dirt from it. It is probably best to have a plastic garbage bag handy to put it in before any dirt and dust can fall off. Then, remove any plastic or paper wrapping from the outside of the filter, and put it in place of the one you removed. Replace the grill to the air intake, and you’re done.

While furnace filters are great for removing particles from your home’s air supply, they can’t do it all. The ideal set-up is furnace filters used along with one or more indoor air purifiers to minimize allergens and other harmful substances in the air.

Indoor air pollution is a fact of life, and in many cases the air indoors is less healthy than the air outdoors. Between dirt, pet dander, dust, and various microorganisms, indoor air can get quite dirty. Many people use air purifiers to make the air that they breathe inside their homes cleaner. But like every other electronic appliance, air purifiers get dirty, and when that happens they run far less efficiently, but there is a lot you can do to improve its efficiency if you’re a reasonably confident do-it-yourselfer.

Home air purifiers are fairly simple devices, and periodic maintenance according to the instruction manual can keep them running efficiently.

You’ve probably at some point noticed a layer of dust built up on top of your television or on a table in your home and wondered just how much of the stuff their is floating around in the air. Believe it or not, in an average home, every cubic foot of air has some 3,000,000 particles of dust suspended in it!

Air purifiers come in two basic types: mechanical and electronic. With a mechanical air purifier, a fan draws air through one or more filters. Typically, a pre-filter removes the biggest matter (such as pet hair), and then a filter with activated charcoal is next in line to remove odors. Third is usually a high efficiency particulate air (HEPA) filter, which removes more than 99.97% of particles that are 0.3 microns in diameter or larger.

Electronic air purifiers use a simple device called an electrostatic precipitator to remove particles like pollen and smoke from the air. Electrostatic precipitators charge air particles positively and then traps them on a grid that is negatively charged. This type of air purifier often contains a pre-filter and perhaps an activated carbon filter to get rid of dust and odors as well. Some of them also contain an ionizer, which is not the same thing as an electrostatic precipitator. An ionizer releases negatively charged ions (and sometimes ozone) into the surrounding air to trap dust particles.

Possible Air Purifier Problems

Depending on how many different filters and features an indoor air purifier has, a number of things can go wrong. Many of them are simple problems that you can fix yourself. Problems such as a dirty precipitating cell, dry motor bearings, clogged filters and air intake, bent collector plates, or broken ionizer wires can often be fixed right at home.

How to Fix Common Air Purifier Problems

1. Cleaning Grill and Filters

For a mechanical air purifier, the first step is to turn the machine off and unplug it from the wall.

Usually there will be release buttons that allow you to remove the intake grill containing the foam pre-filters. Do this and remove the filters. To clean the foam filters, remove them and vacuum them through the grill (so the vacuum won’t attach itself to the filter while you’re using it).

Next remove the screws that hold the filter housing. Vacuum or clean with a soft cloth. If you use a vacuum, keep the screws and other small parts that could be sucked up by the vacuum away from the part you’re vacuuming.

2. Cleaning the Fan

If you need to get to the fan, take out the long screws that hold the housing together and gently pull the two halves of the housing apart.

The fan will have a locking ring on the end of the motor shaft. Put on a pair of safety goggles and remove the fan by twisting or prying the locking ring, but be very careful that you don’t bend the ring.

Take out the screws that hold the motor housing and the switch together. Pull the motor housing apart so you can see the motor. At this point, the switch module should slide out from the housing. You can clean the parts off with a soft cloth.

3. Replacing Broken Ionizer Wires

You can replace broken ionizer wires with replacement wires. Your owner’s manual for the air purifier will tell you where you can get replacement wires. Making sure that the air purifier is turned off and unplugged, remove the precipitating cell according to the owner’s manual instructions. Generally, you use a pair of needle nose pliers to disengage the wire spring from the connector on each end. You may need to press down on the connector with a screwdriver to free the wire. then you reverse the procedure to put a new wire in place.

3. Testing the Precipitator Cell

If you want to test the precipitating cell, you need to be familiar with using a multimeter. If you’re not, you probably shouldn’t do this. First, remove the precipitator cell from the machine. Set the meter for Resistance x 1, which may be labeled Rx1 on your meter. Clip one probe to the frame of the precipitator cell, and then touch the other probe to the ionizer terminal, then touch it to one outer collector terminal, and then the other outer collector terminal. If your reading is "1" (which means "infinity"), the cell is working properly. If you get a lower reading, the cell has a short circuit and you need to replace it.

With the right tools and information you can pretty much repair any living air, shaper image (ionic breeze), oreck, ecoquest and even the full range of Honeywell purifiers. If you follow our guide and your purifier still does not work then you will likely have to take it to a electronic appliance specialist.

The Airpura P600 is a top of the line air purifier with a top of the line price: $1,000. It is made in Quebec by Airpura Industries, Inc. This model has not only a high efficiency particle air (HEPA) filter, but also a carbon filter, a pre-filter, an ultraviolet lamp, and a titanium dioxide photocatalytic oxidizer. It has a high powered 560 cubic feet per minute fan (measured without the filters installed), and is one of the most powerful on the market. Though Airpura claims that the machine can purify the air in a 2,000 square foot area, practically speaking, it is probably more like 700 square feet, which is still pretty large.

The particular combination of filters in the Airpura 600 filters out a number of substances, including radon, formaldehyde, mercury vapor, exhaust fumes, molds, and a number of other substances you don’t want in the air you breathe. The pre-filter can be vacuumed with a brush attachment on a regular vacuum once a month and is expected to last for 12 months. The carbon filter really does its job, with its two inch thick carbon beds. The life of the carbon filter is estimated to be 24 months, but will vary depending on factors like indoor pets and cigarette smoke. The HEPA filter can last three to five years under normal use.

Airpura’s ultraviolet lamp is much more powerful than the ultraviolet lamps in other air purifiers and lasts for 13 months. The titanium dioxide photocatalytic oxidization grid, which is activated by ultraviolet light, breaks airborne particles down into smaller, non-toxic pieces. It is claimed to last for 18 months. This air purifier is powerful enough for use by people with compromised immune systems and those with sensitivities to multiple chemicals.

Nice features of the Airpura P600 include upward air flow with 360 degree uptake, which reduces drafts, and its extreme quiet at its lowest setting (28 decibels). On the highest setting, it registers at 62 dB, which is fairly quiet for the amount of power this air purifier has. The Airpura P600 is cylindrical, 22 inches high, and 15 inches in diameter. It is heavy at 45 lbs., but is on wheels.

Complaints are mostly limited to the high price of the air purifier itself, and the high price of replacement components like filters and the UV lamp. Replacing these on the recommended schedule could easily bring maintenance costs close to $500 per year. Another complaint is that it does not have automated controls, and no odor or dust sensors to automatically adjust the speed to match the level of air impurities. Such features are found on many less expensive air purifiers. There is also no remote control, which is a feature starting to be available with more mid-range air purifiers. Except for these drawbacks, the Airpura 600 is a high-end air purifier that is well built and does its job very well.

The Advanced Pure Air Newport 9000 is marketed by Real Spirit USA and is manufactured in China. It strongly resembles the Mitsubishi MHI-6800 Intelli-Pro, with a futuristic design and shape. The Advanced Pure Air Newport 9000 is sold at Costco, Sam’s Club, Amazon, and Target for just under $280. While it doesn’t contain any breakthrough technology, it does contain several air cleaning technologies in one package. It monitors air quality for both dust and odor and has an LED four-level display showing indoor pollution levels as well as a sensor that indicates when the filters need to be replaced or when the electrostatic collection grid must be cleaned. The fan speed adjusts to pollutant levels, and it runs fairly quietly on all speeds.

Measuring 13.5 x 10 x 25.6 inches, the Pure Air Newport 9000 has air flow of 106 cubic feet per minute, which is fairly low power. While the manufacturer says that the machine can be used in rooms up to 750 square feet, this is a stretch. It is more suited to rooms of under 200 square feet in size for effective levels of air turnover. This air purifier has a series of filters including a washable pre-filter, an electrostatic precipitator, an activated carbon filter, a high efficiency particulate air (HEPA) filter, a photocatalytic oxidizer, an ultraviolet light, and a negative ionizer.

The ultraviolet light is designed to kill dangerous microorganisms. It is a six watt lamp that emits at 254 nanometers, which is not very high powered. The electrostatic precipitator must be cleaned frequently and regularly to keep it working properly. This is true for many models that use electrostatic precipitators. But even when the electrostatic grid is dirty, the HEPA filter will continue to work, and if the grid is kept clean, the HEPA filter will last longer.

The frequent cleaning of the electrostatic grid is perhaps the main gripe of users, but this is true of many air purifiers in this price range. It does not produce any ozone, and odor removal is slightly above average. The gaskets and seals do their job well, and this helps eliminate problems such as dirty air bypassing the filters. Each filter can be replaced independently, which is convenient for those who don’t like having to buy a suite of filters at once. The filters are inexpensive as well. Overall, the Advanced Pure Air Newport 9000 is a decent machine for the price. It is attractive, convenient, and easily portable. Though the series of filters and cleaners may be a bit of overkill, all the technologies are useful and the only drawback is the need for keeping the electrostatic grid clean for optimum performance.

The 3M Filtrete Ultra Clean Air Purifier FAP02-RS (FAP02 for short) is sold at big retailers like Walmart, Amazon, and Target. While they generally receive positive reviews, this air purifier does not use a high efficiency particulate air (HEPA) filter. Rather, it uses an electrostatic filter that draws on 3M’s experience making furnace filters and particle respirators. It is designed for rooms up to 160 square feet. "Filtrete" is the charged electrostatic medium used in this air purifier. It acquires an electrical charge because of friction as the air passes the rectangular fibers that make up Filtrete. It is great for pollen and one-micron sized particles and dust.

Filtrete fibers can be spaced far enough apart that it doesn’t impede air flow as much as a HEPA filter does, and because of this, the FAP02 is very quiet and doesn’t use a lot of electricity. The electrostatic filter is great at removing pollen, which is enormous in size compared to the particles that a HEPA filter would catch. It does not claim to remove odors or chemicals from the air. The Filtrete filters need to be changed every three months and cost $10 to $15 each. There is no pre-filter and no screen to catch large debris like pet hair.

Some pet owners have complained that the filters become clogged very rapidly with pet hair. The expected lifetime of a Filtrete filter is only one month in a house with pets. Another problem with the Filtrete filter and other electrostatic filters is that particles build up on the charged surface, and the efficiency goes down. Some purifiers have washable, reusable filters, but the ones on the FAP02 are not washable, but must be replaced. There are two filter reminder systems provided with the machine: a sensor that senses particle accumulation on the filter and a warning light, and a 90 day countdown timer that the user can set.

The dust and debris are bound electrostatically, so vacuuming won’t make the filter effective again. However, some users say that vacuuming the back of the filter and the air intake can keep flow rates good. There are some aftermarket companies that make less expensive filters, but they have  been found to be inferior in performance to the actual 3M replacement filters.

The 3M FAP02 measures 16 x 7.25 x 22 inches and weighs 12 lbs. It is a good bet for people with seasonal pollen allergies and those sensitive to dust, but for those with chemical sensitivities, it will do little to nothing to help. However, the FAP02 does not emit ozone, which is good for those with sensitive respiratory tracts. This air purifier comes with a one year limited warranty, and there is no question that 3M knows a lot about electrostatic filters and filtration in general. In short, the FAP02 (particularly if you can find it on sale) is a decent machine for those who are sensitive to pollen and dust, and who use the purifiers in relatively small rooms.

The Coway AP-1009CH Air Purifier is built in Korea by Woongjin Coway. The brand was introduced to the U.S. in 2007, and was rebranded by retailers like Lowes and Sears. Coway dominates the air purifier market in Korea, claiming 40% of sales there. The AP-1009CH is a mid-market product at $279 and is sold by Amazon, Walmart, and AirPurifiersAmerica.com. EPA Energy Star states that the Coway AP-1009CH has a clean air delivery rate (CADR) of 186.9 for dust, 149.9 for smoke, and 203.8 for pollen (for an average of 180). These rates make this air purifier suitable for small and medium rooms.

The AP-1009CH has a three stage filter system and four fan speeds, from silent to turbo. The first filter is a washable pre-filter, which is followed by an activated carbon filter for removing odors. The main filter is a 3M HEPA filter that is designed to capture 99.97% of particles greater than 0.3 microns in size. The user manual suggests that when vacuumed regularly the HEPA filter can last up to three years. The pollution indicator is a lamp that goes from blue to red depending on air quality levels. The indicator resembles a mood ring.

This air purifier has a rounded, futuristic shape and is pitched toward women, with floral designs on the product literature. Complaints about the AP-1009CH air purifier have been few, with some users reporting a temporary odor when the machine is switched on for the first time. It is extremely quiet, at only 22.4 decibels, which is suitable for sleeping. It measures 25.8 x 14.3 x 8 inches in size and weighs 13 lbs. It stops automatically when the front cover is open or removed. This air purifier earned the EPA Energy Star rating, using only 37.8 watts on its highest setting. It comes with a one year warranty.

The bottom line is that even though the initial price may seem high, the AP-1009CH has low maintenance costs and energy consumption. It is very attractively designed and suitable for those who want clean air, but it is not powerful enough for those who have serious health issues. The washable carbon filter is fairly light duty, but can tackle odors fairly competently. It is stylishly designed, very quiet and is considered a good value in terms of price and performance.

The Panasonic F-P15HU2 air purifier retails for around $540. It is a small air purifier with a high efficiency particulate air (HEPA) filter (model F-Y15XS, $36) and a charcoal filter (model F-Y55XS, $28). This is an automatic, electronic air purifier that is a good choice for a single room. For its price range, the F-P15HU2 is quiet. When set on a low, but still useful, air volume exchange rate, it is quiet enough for undisturbed sleep. Rated as a "best buy" by consumerguide.com, the F-P15HU2 does not include a pre-filter that some air purifiers use as protection for the main HEPA filter. However, it does have a pre-filter layer attached onto the HEPA filter that can be cleaned easily. The HEPA filter removes 99.97% of airborne particles of 0.3 microns in size and larger, though on high speed, there is some loss of efficiency. The deodorizing filter has activated charcoal and lasts up to one year.

With three fan speeds, plus a "super" burst mode setting for quick particle removal, the F-P15HU2 claims a clean air delivery rate (CADR) of 150 and will clean rooms of up to 216 square feet. The decibel levels on each of the four speeds, starting with the highest are: 56 dB, 48 dB, 40 dB, and 30 dB. The sensor monitors particle levels and lights up LED lights on the monitor to indicate the approximate particulate level. The more red LED lights that are lit up, the dirtier the air. The fan will automatically work faster until the air is cleaned. When the air has been suitably cleaned, the LED lights turn green, and the fan speed slows. It can also be used in timer mode to turn on and off at specified times, and it has an interval mode for energy savings.

User-reported drawbacks of the F-P15HU2 include energy use, which is 101 watts on the highest speed, down to 43 watts on the lowest. Automatic controls, timer mode, and interval mode can effect some energy savings. Some users report that replacement filters can be hard to find, so it may be wise to find a supplier online or elsewhere before committing to the F-P15HU2. The carbon filter does not have carbon volatile organic compound (VOC) capability, so it is not tops at removing odors and gases from the air.

Overall, the F-P15HU2 is highly ranked by users, earning five stars out of five from seven Amazon customers. It is a compact (15 5/8 x 21 1/4 x 6 inches) and convenient design with a cord that’s just over eight feet long. It will fit on shelves and wide window sills and weighs about 14 lbs.