Air Purifier Technologies: HEPA Filter

HEPA (High Efficiency Particulate Air) filter material was first invented in the 1940’s and used during World War II by the United States Government. It is used in the Manhattan Project to stop the radioactive particles from escaping out of the scientific and military laboratories.

radiation suit

HEPA filters are composed of microfibers that are between 0.5 and 2.0 microns (one-millionth of a metre) in diameter and randomly arranged to form flat sheets. Microfibers are made of a glass-like substance boron silicate, shaped into flat sheets like the process of making paper. To make the filter, the flat microfiber sheets are pleated and separated by baffles. The reason why the microfibers are pleated is to increase the filter surface area and the baffles will guide the air into the filter.


To force the air into the HEPA filter, a fan is used. The HEPA filter is very efficient in removing tiny contaminant particles in the air due to its very tiny, microscopic microfiber holes. The microfiber spores or holes measure more than 0.3 microns. The HEPA filter is expected to capture 99.97 percent of particles with a size of 0.3 microns. The common misconception about the HEPA filter is that the filter is like a strainer that blocks the particles with a diameter more than 0.3 microns and let particles less than 0.3 microns pass through. Unlike the strainers, where particles are blocked when it is larger than the strainer’s hole, HEPA filters are designed to block particles smaller than its holes.

HEPA filters

HEPA filters can remove the following contaminants:

HEPA contaminants chart source


HEPA is considered today as the most efficient particulate filter type available, according to the independent authorities. A lot of commercial HEPA air purifiers also feature other air purifier technologies depending on the type of indoor air contaminants. source

There are four mechanisms on how particles are trapped in the HEPA filters. They are as follows:

1. Interception – is a mechanism where the mid-sized particles following the flow of the airstream gets attracted to the fiber’s stronger force at a distance of 1 radius of a fiber and stick to it.


2. Inertial Impaction – is a mechanism that occurs to large particles (above 0.4 microns). At first, large particles follow the path of the airstream and when the air change direction as it passes around the fiber, the large particle continues to its initial path and then collides with the fiber. As the air flow speed and fiber density increases, inertial impaction also increases.

Inertial Impaction

3. Diffusion – particles that are very small (less than 0.1 microns), are delayed and impeded in their path through the filter and will not follow the air’s streamlined path because they will collide with the gas molecules. This behavior is the same to Brownian motion. The delayed path raises the possibility of the particle to be captured by either interception or inertial impaction. Diffusion mechanism, at lower air flow speed, is dominant.


4. Sieving – also called “straining” is the most common and simplest mechanism in filtration. It works the same as the kitchen strainer. Particles larger than the pores or holes of the fiber sheet matrix are blocked from passing through.


Below is the filter efficiency chart of the four filtration mechanisms:

HEPA filter efficiency



When buying air purifiers, it is best to choose the ones with “True HEPA” or medical grade HEPA filters. You must be careful when buying HEPA air purifiers, because not all air purifiers with HEPA filter in the market can achieve the efficiency of 99.97 percent in removing particles less than 0.3 microns in size.

Types of Air Purifier Technology That is Best for Allergies

Some people blame the air outside for their allergies and so they end up spending 90 percent of their time inside the house. Most of us think that the air inside our house is cleaner. Well, all of them are wrong. According to the United States Environmental Protection Agency, the pollutants are 25 to 100 times higher in the air inside compared to the air outside.



Allergies are the body’s specific immune system reaction to a typically harmless substance such as medicines, pollens, or certain foods. source


For better understanding of what allergy is, below is an animation video from

Some common allergies include:

common allergies



Air purifiers are not a solution for food allergens that causes food allergies, since air purifiers can only filter and clean the air. There are many types of air purifier technologies available according to These are HEPA filter air purifiers, Ozone air purifiers, Carbon air purifiers, Ionic air purifiers, Ultraviolet light air purifiers, and Purifying hydroxyl radicals air purifiers.

Below is a comparison chart of air purifier technology that can help us determine the best for removing airborne allergens.

comparison chart



Based on the comparison chart, HEPA and Ionizer air purifiers can remove allergens like dust, pollen, and mold spores. While the Ultraviolet lamp and Carbon air purifier, can only remove some of the allergens. Some air purifier brands combine two or more of the air purifier technologies.

We will now concentrate on the two air purifier technologies below, that can remove airborne allergens that cause allergies.

1. HEPA filter air purifier

HEPA filter 2

HEPA stands for High Efficiency Particulate Air. HEPA filters are originally designed to prevent radiation from coming out of the laboratories during World War II. HEPA filters use a cloth like filter that can trap 99.7 percent of airborne particles 0.3 microns or bigger in size. HEPA filters can be very efficient in removing practically any unsafe airborne particles in the indoor air. HEPA filters from air purifiers are replaceable. The service life of the HEPA filter will depend on how dirty is the air inside. Due to its high air resistant filter, this type of air purifier needs a powerful fan for the air to pass through. Because of that, some people complain of having a noisy machine.

hepa air purifier 2

Advantages: Once the airborne allergens are trapped, they could not return to the air.

Disadvantages: Can’t remove odors, cigarette smoke, gases, or chemical fumes.

2. Ionic Air Purifier

air ionizer

air ionizer 3

Unlike the HEPA air purifier, the Ionic air purifier doesn’t have a cloth like filter. The ionic air purifier works by ionizing the air. After the ionization, the airborne particulates will gain negative and positive charge.

air ionizer 2

There are two reasons why airborne particulates are ionized. First, ionic air purifiers have charged collection plates that will attract the oppositely charged airborne particles. These kind of ionic air purifiers are called “capture” ionic air purifiers. Second, the negative and positive charged particles will attract each other. Due to this attraction, the particles will increase in weight and will fall into the ground. These ionic air purifiers don’t have a charged plate, they simply release ions through the air. Other people prefer ionic air purifiers over HEPA air purifiers because they are very quiet.

ionic air purifier 2

Advantages: Even if the very fine airborne particles are several feet away, they can be removed anywhere in the room.

Disadvantages: They can’t remove odors and can’t kill germs. However, they remove the germs from the air.

8 Ways To Get Rid Of Cooking Odor

Many people love to cook at home but hate the smell that cooking leaves in your kitchen and even all over the house. Cooking spicy food, exotic recipes and roasting can leave the lingering smell all over your home especially if your home is fully air conditioned.

But that should not prevent you from enjoying the luxury of staying with your family at home and enjoy the fun of cooking. There are ways to eliminate the unwanted odor.

1. Air Fresheners

air freshener

Air fresheners are commercial or consumer products used in homes and restrooms to make the air fresh.

How air fresheners work? According to Multiple Chemical Sensitivity (MCS) America, air freshener works in combination or one of the following:

how air freshener works


But despite the air freshener’s positive name, MCS America said that air fresheners do nothing or little to make the air fresh.

air fresheners do little

air fresheners do little 2


MCS America is not alone for having negative feedback in using air fresheners. also posted that many cleaners and air fresheners may pose health risks when used indoors.

To avoid the health risks from using chemical air fresheners, use homemade air fresheners instead.

2. Proper ventilation


Ventilation is the process of providing fresh air to an enclosed room and taking away contaminated air outside. Kitchen is one of the busiest places in your house. You you use it 3 times or more to cook food every day. Because of that, proper ventilation is recommended to reduce and eliminate cooking odors. For proper ventilation, here is a document in portable document format: “Ventilation – The Secret to a clean, odor free kitchen” courtesy of ARAcontent.

ventilation fan

3. Simmer Potpourri

simmering potpourri

Potpourri is a kind of air freshener made from cones, seeds, leaves, and dried flowers. source

Since it is a kind of air freshener, it only masks the odor using its scent. If you want to make an easy homemade simmering potpourri, below is an instructional video:

4. Vinegar


Vinegar is a multipurpose liquid as a result of ethanol fermentation. Acetic acid is the main ingredient of vinegar that gives it an acidic taste. It is also famous in household cleaning applications. source

Because of the vinegar’s popularity as a multipurpose liquid, Richard Sweeney, an eHOw contributor posted instructions on how to eliminate odors with vinegar.

clean with vinegar

5. Make some coffee

coffee aroma

Coffee lovers will love this idea. Coffee is a brewed drink coming from roasted coffee beans.

coffee beans

The idea here is to mask the cooking odor with the aroma of coffee. It will not only mask the odor, according to, just smelling coffee helps head.

6. Baking Soda

baking soda

Some people think that baking soda and baking powder are the same. But actually, they are not. So, what is the difference between baking soda and baking powder? Baking soda is pure sodium bicarbonate, while baking powder contains sodium bicarbonate, acidifying agent and drying agent.

Baking soda is a chemical salt with various practical uses. Baking soda is commonly used in baking as leavening agent.


baking soda cleaning

So, How to remove odors from home using baking soda? Well, just sprinkle the baking soda into the rugs and carpets and leave it there overnight. Then vacuum it all up in the morning when you wake up. Put a tablespoon of baking soda combined with vinegar into your sink drain to freshen it.

7. Scrubbing


Some cooking odors came from the sticking grease from cupboards, ceilings, walls, cookware and stoves. If you clean those areas, make sure that you include those tricky areas.

An eHow contributor, Deborah Waltenburg will also help you on how to clean cooking grease.

8. Air Purifiers

Air Purifiers are made to clean the air pollutants inside your house. Actually, the level of pollutants in the air inside is 25 to 100 times HIGHER than outside according to the United States Environmental Agency.

Not all air purifiers can remove odor. Only those air purifiers with carbon filter and ozone generator can remove odor, like the odor from cooking. source

comparison chart

Carbon air purifier – this kind of air purifier uses activated carbon filters, a highly effective filter that captures odor, cigarette smoke, chemical fumes, and gases.


carbon air purifier 2

Ozone generator air purifier – this kind of air purifier uses ozone, an oxidant that is highly reactive in destroying chemicals and bacteria.


ozone air purifier 2

5 Ways Of Eliminating Cigarette Smell From Your House

Cigarette is made from fine tobacco leaves wrapped and rolled in a thin paper to form a cylinder. We all know that smoking is dangerous to our health. Many countries around the world put warning message on tobacco packages. The purpose of the warning message is to educate people on the harmful effects of cigarette.

cigarette warning

For non-smokers, you may be puzzled or had a hard time understanding why other people smoke even if they know the health risks involved. The effect of smoking on human health is very serious.

So, what is in a cigarette? According to American Lung Association, there are about 600 ingredients in cigarettes and there are over 4000 chemicals produced when the cigarette is burned. 50 of those chemicals are known poisonous and can cause cancer.


When you are a cigarette smoker, it is very hard to get rid of the cigarette smell from your clothes or your house. This is due to the variety of chemicals from the cigarette. Since the smell coming from the cigarette is in smoke form, it can easily seep through the clothing, lampshades, curtains, furniture, bedspreads, rugs, carpets, flooring, walls, etc.

There are ways of eliminating cigarette smell from your house. They range from natural chemicals to air purifiers. These include:


1. Vinegar

vinegarVinegar has been used by ancient people for thousands of years. It is very famous as a condiment and food ingredient. Vinegar is an acid created from ethanol fermentation. What gives the vinegar its acidic taste is the fact that its key ingredient is acetic acid.



The acetic properties of vinegar make it perfect as household cleaner and odor eliminator.

What cause cigarette smell are the leftover tars and resins from smoking. Known for its acetic property, vinegar will remove those leftovers from a variety of surfaces and some fabrics. The steps on how to remove cigarette odors with vinegar can be found here.

Due to its cleaning power, compiled 1001 uses for white distilled vinegar.


2. Cleaning the carpet or rug

carpetIf you bought a house from a heavy smoker, there is a big chance that leftovers from the cigarette have accumulated in the carpet. What you should do is to clean the carpet immediately because the longer the cigarette smell stays in your carpet, the harder it is to remove.

washing carpet

There are 5 steps in deep cleaning and deodorizing your carpet using laundry detergents according to Mel Frank, who completed a wide variety of writing assignments for a number of publications that include CNN and various websites.


3. Baking Soda

baking sodaBaking soda also called sodium bicarbonate or bicarbonate of soda is a famous chemical salt commonly used as a leavening agent in baking. What makes the baking soda effective in removing cigarette smell is its action of neutralizing the scent molecules.


You can dust the furniture, beddings and carpets with baking soda powder and then leave it there to settle for 3 to 5 hours or overnight. When the powder absorbed enough smell, you can easily use the vacuum cleaner to clean it up.


baking soda carpet

4. Curtains and Furniture need to be cleaned

                       curtain    furniture

Curtains are used to control the light and insulation of the house. Curtains and furniture in our house are mostly made of cloth. Cloth has a lot of tiny holes that can easily let the air pass through and filter larger particles like from the cigarette. Because of that, cigarette smell can easily cling into the cloth.

curtain cleaning

You can remove the cigarette smell or any other odor by following these 8 simple steps on how to remove smoke smell from curtains by Jesse Gunther.

For cleaning the furniture, Isaiah David posted instructions on how to remove smoke smell from furniture.

furniture cleaning

5. Air Purifiers

According to, there are 6 types of air purifier technology available today. These are HEPA, Ionizer, Ultra violet lamp, Carbon filter, Ozone generators, and Purifying hydroxyl radicals air purifier.

comparison chart

Based on the chart, only the Ionizer, Carbon filter, and Ozone generator type air purifiers can remove cigarette smoke. For odors like cigarette smells, only Carbon filter and Ozone generator can get rid of it.

Carbon Air Purifiers – this type of air purifiers use activated carbon as air filter to adsorb odors and bond to the carbon.

Activated Carboncarbon air purifier

Ozone Air Purifiers – this type of air purifiers use highly reactive oxidant ozone that breaks down substances in the air and turning them into other materials. But there is a safety precaution you should take before using these types of air purifiers.


ozone air purifier


Zen Living Professional Air Purifier

The Zen Living Professional Air Purifier is a UVC Germicidal digital air purifier with HEPA filter that is best for regulating allergies. For odor eliminating features, it is recommended to use the Carbon Filter Zen Living Model. zen-living-air-purifier-with-remote-wood-grain When you first turn the unit on, the air purifying function will automatically work. To reduce the number of dust particles, this air purifier will create negative ions that attract particles of dust round the clock. It has a separate control for the activated oxygen. In occupied spaces, the activated oxygen is usually retained at modest levels. To ensure the removal of odors, the air purifier may be set to a high level for a certain time period. If you are away, you can automatically set the timer to deodorize your office or home completely. Ozone that is unused returns back to regular O2 around 1 hour. zen-living-air-purifier-with-remote-wood-black This product removes pet dander, tobacco, odors, and smoke. The Zen Living Professional Air Purifier features an air sanitizer that significantly reduces bacteria, mildew, and mold that cause illness from the workplace or home. As the germs flow through the unit, the UV-C germicidal light will exterminate them. The Zen Living Professional Air Purifier is designed to have a larger airflow. There is four steps process when the air is purified. The first step is the pre-filter that traps big particles like hair and then the air goes to the second stage which contains a washable HEPA filter that traps airborne pollutants, pollen, and dust that cause symptoms of allergy. The third stage is the stage that eradicates all types of microorganisms by using the UVC Germicidal light. The fourth and final stage create negative ions that attract and attach to the bacteria, germs, and dust. When those harmful particles collected will be heavy enough, they will fall into the ground and can easily be vacuumed by vacuum cleaners. In that way, it will no longer be a threat for the irritating respiratory tract. The unit comes with activated oxygen for removing odors but it is suggested not to use this feature for allergy-fighting, because it may have a negative effect on people suffering from respiratory problems like severe allergies. HEPA filter The Zen Living Professional Air Purifier weighs 17 pounds and generates 11,300,000,000,000 ions per second or 11.3 Trillion ions per second! What generates the ions is the 12-15 Kilovolts power supply. This unit also operates silently with its 12 volts DC 400 CFM five-speed fan. Update April 2020: The Zen air purifier was a good machine back when we originally reviewed it in 2011 but 9 years has been a long time for this type of technology and things have moved along at a rapid pace. The following air purifiers are those that we are happy to recommend to people looking for an air purifier:

1.Austin A250B1 – Best Overall
Austin Air A250B1 HealthMate Plus Junior Air Purifier, Black
  • Designed for people living in smaller spaces and specializes in the reduction of harmful chemicals, noxious gases, VOC’s, formaldehyde, and sub micron particles for individuals in the most contaminated of settings
  • Broad spectrum adsorption offers protection for people exposed to smoke from wildfires, those living close to busy highways, and people with sensitivity to certain chemicals and gases found in the home
  • True medical grade HEPA filter removes 99.97% of all particles larger than 0.3 microns; over 270 cubic inches of activated carbon impregnated with potassium iodide and zeolite filtration removes odors, gases and chemicals including formaldehyde and benzene
  • 3 speed settings for fan; 360 degree intake system draws air into all sides of unit, passing air through a 4 stage filter
  • Eases headaches and reduces nausea related to chemical exposure; helps reduce coughing, wheezing and sneezing, dry mouth, runny nose; reduces night time allergies and asthma attacks, snoring, and helps you sleep better; strengthens the immune system

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2. Medify MA-40 2.0 – Great if you can afford

Medify MA-40W2 V2.0 Medical Grade Filtration H13 True HEPA for 840 Sq. Ft. Air Purifier, 99.9% | Modern Design - White (2-Pack)
  • Medical Grade H13 Filters (higher rated than True HEPA) 99.9% particle removal. H13 True HEPA is considered medical grade air filtration, the unit alone is not a medical device.
  • Cleans a room up to 1,600 sq ft in one hour, 840 sq ft in 30 minutes, 420 sq ft in 15 minutes (CADR 330)
  • To make V2.0 quieter in 'Sleep Mode' and Speed 1 the ionizer is automatically turned off, on speed 2 and 3 it can be turned on/off as needed | CARB, Energy Star & ETL certified.
  • Tempered Glass panel (like your cell phone, easy to clean, won't scratch like cheap plastic models), Sleep mode and 3 fan speeds, 8 hr timer, night mode, child lock
  • Genuine Medify Replacement Filter: B07MTQFFNT, 110 Volt units, USA registered Lifetime Warranty

3. LEVOIT CORE 300 – Quite a machine for less than $100

LEVOIT Air Purifier for Home Allergies Pets Hair Smokers in Bedroom, H13 True HEPA Air Purifiers Filter, 24db Quiet Air Cleaner, Remove 99.97% Smoke Dust Mold Pollen for Large Room, Core 300, White
  • Genuine Replacement Filters: Search for core300-rf or core 300 replacement filter for Replacement Filters. Use genuine Levoit replacement filters to maintain the best performance and to ensure what you're buying is worthy of your investment
  • Higher Purify Performance: Use the Core 300 to fill your environment with crisp, clean air. Its Vortexair Technology creates a stronger air flow, CADR number is 230+m3/h, allowing it to cover up to 219 sq. ft. AC 120V/60HZ for USA and Canada
  • Improved Filtration: With larger expansion area and longer length than others, the H13 Ture HEPA filter works with ultra-fine Pre-filter and activated carbon filter, trapping 99. 97% of fine particles and allergens as small as 0. 3 microns and large pollutants such as dust, pet dander, smoke, mold, pollen
  • Most Silent Air Cleaner: The noise level is nearly voiceless at sleep mode with only 24db, its QuietKEAP Technology reduces noise so you can sleep in a restful and soothing indoor environment
  • Ultra-long Service Life: Industry leader provider's bearing makes this levoit core300 hepa air purifier durable and reliable. The AC capacitor motor uses durable high-precision bearing, and excellent internal structure increases abrasion resist, which obviously extends the life of machine

4. Coway Airmega 300 – Not cheap but great for large spaces

Coway AP-1512HH Mighty Air Purifier with True HEPA and Eco Mode
  • Coway Mighty (AP-1512HH) is designed to accommodate room sizes up to 361 sq.ft (CADR: Dust 246 / Pollen 240 / Smoke 233 cb. ft.).
  • 4 Stage Filtration System (Pre-filter, Deodorization filter, True HEPA filter, Vital Ion) captures and reduces up to 99.97% of particles 0.3 microns in the air, including pollen, pollutants and other allergens. It also reduces volatile organic compounds and reduces odor.
  • Coway Mighty pollution sensor communicates indoor air quality in real-time. The brightly colored LED lets you know how clean or dirty your indoor air is every minute of the day. And it features a timer, and filter lifetime indicator.
  • Fan speeds available in 1, 2, 3 stages by manually setting up. While auto mode automatically optimizes the speed setting 1 through 3 based on the level of indoor air quality. When no pollution is detected for 30 minutes, the fan will automatically stop and set as Eco mode to save energy.
  • Timer feature allows the machine to run 1/4/8 hours before automatically powering off.

5. Sharp FPF30UH – Great for small spaces and tight budgets

Sharp, White FPF30UH True HEPA Air Purifier for Home Office or Small Bedroom with Express Clean. Filters Last up-to 2 Years for Dust, Smoke, Pollen, Pet Dander, 143 Square Feet
  • SMALL ROOMS: Designed for Rooms up to 143 sq. ft.
  • CADR Dust (101) / Smoke (92) / Pollen (109)
  • Long-Life TRUE HEPA Filter Lasts Up-to 2 Years (actual filter life will differ depending on the environment)
  • True HEPA Filter Captures 99.97% of Allergens as Small as 0.3 Microns that pass through the filter
  • The Library Quiet, Sleep Setting is Perfect for the Bedroom or Home Office (as low as 23 dba)

Sharp’s KC860EKW Air Purifier with Humidifier

Using air purifiers are beneficial for people who are suffering from lung problems like asthma and other ailments which cause difficulty in breathing. Investing in air purifiers like the Sharp KC86EKW is a good decision to eliminate these health problems.

The Sharp KC860EKW is a heavy duty air purifier which combines Sharp’s Plasmacluster ion technology and a powerful humidifier. It can purify a large room air for up to 48 square meters.


This air purifier has a 3-stage filtration system, high efficiency HEPA-Filter dust collector and odor filter. The negative and positive ions of this machine will attach to the airborne particles and make them harmless, so the air quality of your home or office will definitely improve.

SSharp air purifier 2

The humidifying function of this machine uses a system of natural evaporation that maintains and monitors the humidity of the room automatically. Furthermore, the KC860EKW has a 3-step odor monitor with a washable deodorizing filter that eradicates indoor smoke and odor.

10 Historical Air Purifier Inventions

An enemy you can’t see, taste, or touch is not far from you as you read this sentence.  It’s not an enemy like a lion or a shark that you can avoid. No.  This enemy kills us by working with the very thing we can’t live without… breathable air.

I’m talking about toxic fumes, and they are as ubiquitous today as cars and factories. And if it wasn’t for inventions like the following 10, you would drop dead before you finished this line.

1. The Stenhouse gas mask, 1854

Stenhouse gas mask

A chemist by trade, John Stenhouse began experimenting with charcoal filters as an air purifier as early as the 1850’s.  The unit he devised called for wire gauze “filters”, which held powdered charcoal as the filtering ingredient. His findings led to the invention of the gas mask, used in London factories as a personal “air purifier” to protect workers from toxic gas.


2. Barton’s respirators, c. 1874


Barton's respirators 

In 1874, Samuel Barton filed for patent for the canister gas mask… one of the most advanced air purifiers of the time. Air impurities where lifted as the user inhaled through a tri-layer filtering system, which was strapped to the face via head harness and face cover. The invention also included a revolutionary air recycling system, whereby clean air was cycled through a secondary filter to remove carbon dioxide.


3. Carbon Filtering – 1862

carbon filtering The carbon filter was invented in 1862, and was originally used to purify water.  Its transition into an air purifier occurred in 1872, when Allen and Alvin E. Rice advanced the technology by creating a 2 stage filtration based on activated carbon.  In modern day, air purifiers built around the carbon filter are used to purge air of vapors, odors, and hydrocarbons… as well as the basis of today’s spacesuit breathing system.


4. First Vacuum – 1901


While riding the train, Hubert Cecil Booth began breathing dust laden air through a handkerchief during a moment of inspiration.  The moment spurred Booth on to the 1901 invention of “Puffing Billy”, the world’s first vacuum cleaner. The unit ran on an oil engine and is a precursor for more advanced air purifier systems.


5. First Air Conditioner – 1906


Patents #808 and #897 are the soil from which today’s air conditioner bloomed.  By using centrifugal force and a complex system of filters and coolants, Carrier (the unit’s inventor) birthed a robust air purifier and cooling system.  Not only did his invention purify air and control temperature, but it also curbed humidity and manipulated air circulation.


6. Electrostatic Precipitator – 1908

Electrostatic Precipitator

Dr. Frederick G. Cottrell invented the electrostatic precipitator, a device which created and collected charged particles. Cottrell’s apparatus found use in smelting factories and vineyards, where sulfuric acid and lead oxide fumes which once polluted the air could be collected and eliminated. The technology evolved to become a key component in publically-marketed air purifier units.


7. The First Personal Air Purifier – 1914


Garret Morgan filed for patent in 1914, having invented a device that resembles the mask of an ancient scuba diving suit.  A long tube runs from the mask down to the floor, sitting below lighter-than-air gases. The filter in the “air purifier” itself mimics the body’s mucous membrane, cleansing inhaled air by running it through a wet sponge lining. And what does a user do when the gas is heavier than air? Elevate the tube above the gas…


8. HEPA – Filters – 1940’s

hepa filter

The USA Atomic Energy Commission invented the HEPA filter during the Manhattan Project, seeing a need for a system to clean air contaminated with radioactive particles.  After World War 2, the HEPA filter was released to the public and is now used by air purifier companies as a heavy-duty filtration device.


9. Rufus Stokes  – Air Factory Purification Device, 1968


Rufus Stokes invented the “clean air machine”, a device used on smoke stacks to clean the emissions.  His invention drastically reduced the amount of ash and gases that made it beyond the stacks, leaving behind virtually transparent releases.  The boost in air quality improved the health of people, plants and animals living in the vicinity of commercial furnaces and power plants.


10. NASA Space Air Cleaner Laser – 2004


In an invention that sounds like something out of Star Wars, NASA created the Low-Temperature Oxidation Catalyst (LTOC) in 2004.  LTOC began as a method for lasers to control carbon monoxide in space.  Now, researchers are finding applications for air purification on Earth, using the tech in automobile catalytic converters.


10 Cities With Air You Don’t Want To Breath

In a world of combustion engines and smoke stacks, we are all sucking in poison with every breath.  Invisible to the eye, each puff of air has innumerable particles that destroy our bodies from the inside.  Some parts of the planet are worse than others; the following article outlines 10 cities where it’s most hazardous to breath.

Emissions fall into two categories – ozone pollution and particle pollution.  Today, 1 in every 4 Americans are breathing air contaminated with one or the other (source: American Lung Association).  The very air we breathe has become hazardous to our health.

Statistics from the U.S. EPA show that the average person breathes 3,400 gallons of air every day, with children breathing in more air than adults. This makes our air supply one of our most dangerous heath risks.  “Addressing air pollution is the easiest way to be able to fix someone’s well being… there are all sorts of harmful particulates in the air – link

1. Milan


Pm10 – a particularly insidious particle – causes cancer and respiratory problems.  Take a trip to Milan, Italy and you’ll get more than your fair share.  Legambiente, an Italian environmental group, claims that Milan has more smog than any other European city.  Cars are thought to be the primary culprit, but with a 26% drop in traffic since January (thanks to congestion pricing)  the city‘s residents are hoping the smog clouds blow away.

Source + Image

2. Norilsk, Russia


Blacksmith Institute, an environmental think tank, ranks the Russian city of Norilsk within the top 10 most polluted places in the world.  The world’s largest smelting plant sits in Norilsk, coating the air with nickel and cobalt deposits.  With adults dying 10 years younger than the average Russian plant worker and children developing serious respiratory diseases, the company has finally started taking curative steps.  They’ve even pledged to move the plan outside of the city … eventually.

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3. Pittsburgh, Pennsylvania


Pittsburgh – the Steel City – has more soot, aerosols, heavy metals and exhaust in its air supply than Los Angeles.  This, with a paltry population of about 335,000 residents (Interesting note: L.A. has over 10 times as many residents at about 3.8 million.)  When figuring out the cause, researchers are pointing their finger west; they say dirty air is blowing over from Ohio factories and power plants.

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4. Mexico City, Mexico

mexico city smog

3,000 buses. 8.84 million residents with the corresponding amount of cars, motorcycles and taxis.  A deep valley, enclosing all of that in a 3 sided bowl of mountains and volcanoes… and you have Mexico City. Its natural tendency to limit airflow makes it one of the most polluted cities on the face of the planet.  Being 7,400 feet above sea level accentuates the problem.  And what has the government done to alleviate the problem?  They’ve started a project to retrofit special filters on 25 diesel buses.  Don’t ask about the other 2,975 buses, or the 4 million private cars.

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5. Linfen, China

linfen pollution

Citizens of Linfen, China are strangled by clouds of coal dust as they walk the streets.  The city’s drinking water is laced with arsenic, the same poison used in various chemical weapons.  Linfen may be the world’s most polluted city. China’s lax environmental controls hold some of the blame.  The fact that Linfen is the heart of China’s coal production operations doesn’t help.

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6. Ouagadougou, Burkina Faso


Benzene – a pollutant caused from burning motorbike petrol – and dust particles are 3 times the World Health Organization’s prescribed limits in Ouagandougou, Barkina Faso.  As a result, cases of cancer and respiratory disease are up considerably.

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7. Bejing

Bejing smog

The air in Beijing, China is literally gorged with nitrogen dioxide.  This is the same pollutant that can fatally damage the human lung.  Pollutants are just as prevalent in surrounding Chinese provinces; satellite data shows a 50% spike in breathable pollutants over the last 10 years.

Zhang Lijun, deputy director of the EPA, says the worse is yet to come.  According to Lijun, pollution levels will quadruple over the next 15 years unless China gets a hold on its energy consumption methods.

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8. Tianying, China


An industrial city — though China doesn’t really have any other kind —in the country’s northeastern rust belt, Tianying accounts for over half of China’s lead production. Thanks to poor technology and worse regulation, much of that toxic metal ends up in Tianying’s soil and water, and then in the bloodstream of its children, where it can cause lowered IQ. Wheat has been found to contain lead levels up to 24 times Chinese standards, which are even more stringent that U.S. restrictions on lead. “China has a commitment to environmental protection, but it also has a commitment to industry,” says Richard Fuller of the Blacksmith Institute. “It’s a constant push that’s mostly won by industry.”

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9. Los Angeles County

Los Angeles pollution

Los Angeles metro has the United State’s highest levels of ozone pollution, according to the State of the Air report 2010 (publisher: American Lung Association).  Dr. Norman H Edelman, a chief medical officer for the ALA, says breathing ozone is like “getting a sunburn on your airways.”  Constant exposure increases chances of respiratory disease… not good news for those living in La La Land.

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10. Kolkatta

Kolkatta smog

Calcutta, India has roughly18.4 cases of lung cancer per 100,000 residents yearly, eclipsing Delhi, India in the occurrence of the disease. (Delhi has13.34 cases per 100,000 residents per year.) This is despite having less than half the population count.

Apparently, the city’s high air pollution is the primary cause.  70% of the Calcutta’s respiratory diseases are said to be the direct result of air pollutants, according to a recent study by the Chittaranjan National Cancer Institute.

Suspended Particulate Matter (SMP), an air pollutant, should never have a count above 140 in a healthy environment.  In Calcutta the average SPM count is 211.  Likewise, Respiratory Particulate Matter (RPM) count should never pass 60.  Calcutta almost doubles that figure with a RPM count of 105.

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BONUS 11. Rauðafell, Iceland (yes i know it’s not a city!)

volcano ash iceland

Sometimes nature itself contaminates the air we breathe; it’s almost as if Mother Nature is protecting herself with proactive measures.  This is especially apparent in the wake of the volcanic eruption in Iceland.  Finnu Tryggvason, a farmer in Rauðafell, had to put down some of 4 of his horses in answer to the eruption.  “I would have like to keep them a while longer,” he says, “but circumstances do not allow for that.”

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3 Air Purifiers That Will Actually Clean The Air

If you been on this site before you will know that I spend most of the time moaning about air purifiers that fail to live up the marketing hype. However its not all doom and gloom as I’m now going to tell you which air purifiers are the real deal!

I don’t want you to just take my word for it, so I put in some links to other review sites – please feel free to check them out. I always recommend that people do their own research so search the names of these products on Google…etc

number-1IQAir HealthPro


The IQAir Health Pro purifier is respected by nearly every review website we came across. We love it because it really does what it says on the box. It has a 4 stage filtration process that can block 99.5% of particles bigger than 0.003 microns. Each purifier is hand tested and each comes with a handwritten performance report!

Here is what other people are saying about it:



The IQAir HealthPro air purifier is expensive, but according to reviews it’s the best option for people with severe allergies.



99% of particles removed – Top Marks for 22 air purifiers tested



The IQAir HEPA air purifier is manufactured in Switzerland. It is a testament to precision Swiss engineering. The company behind this unit is in the hospital clean room business.



I still adore my Healthpro, so obviously the best.

Where can you buy the IQAir Health Pro?




number-2Alen A350


The Alen A350 is not that well known and many people will dismiss it because it is only able to clean 400-800 Feet when compared with the likes of the IQair which can deal with up to 1000 feet.

When looking at how this purifier performs in tests you think their must be some sort of mistake made with the price. The A350 costs around $450 which is nearly half the price of an IQair Healthpro. If your budget just wont stretch for the IQair then I would happily recommend the Alen A350.

Here is what other people are saying about it:



In tests, the Alen A350 air purifier has been shown to remove nearly as many allergens from the air as the more expensive IQAir HealthPro



In testing, the Alen A350 finishes second only to the top-ranked IQAir HealthPro in its efficiency at removing allergens.



The Alen A350 and A375UV air purifiers are a good choice for someone looking for an affordable air purifier that has features and performance similar to many higher priced air purifiers.



He says it’s especially good at dust and pollen removal, particularly for rooms of about 250 square feet.

Where can you buy the Alen A350?


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number-3Airgle 750 Air Purifier

airgle-750-air-purifierThe Airgle 750 is a purifier from Korea that needs to be taken very seriously when your looking for a new purifier. This purifier uses 12 filters to clean the air which is probably why it was given top marks across the board in relation to its ability to remove pollutant particles. The Airgle uses a combination of HEPA filters and activated carbon. The only downside is the small amount of activated carbon that is used. I would feel more comfortable with at least double the amount of carbon. What really stood out for me about the Airgle 750 was how quiet it was – produces 23dB when it was purifying 71 cubit feet per minute! Another plus point is that this unit produces zero emissions!

Here is what other people are saying about it:



In independent laboratory tests performed by the Association of Home Appliance Manufacturers, the Airgle 750 air purifier had the highest Clean Air Delivery Rate (CADR) when compared to 159 leading air purifiers.



“Impressed” would be the word to sum up our review of the Airgle 750 Hepa Air Purifier. From the performance of the four true HEPA filters, to the easy glide casters, this air purifier scored high across the chart.



The 750 from Airgle, a contender in the premium air cleaner space, is best for those with serious particulate sensitivity.

Where can you buy the IQAir Health Pro?


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