Tag Archives for " HEPA filter "

Why is my house so DUSTY? Assessing the air currents gives a clue

This article was written in response to an actual problem.  My elderly parents moved into a “barndominium” which was converted from a 35x35’ metal workshop, in 2020.  The walls were insulated with fiberglass batts, and the attic above their 10’ ceilings was insulated with blown-in insulation.  I listened to my mom’s complaints about dust in the house. This is a real problem because the dust seemed to settle very quickly after cleaning, and my father has COPD.  Since the dust seemed to be a whitish colored dust, together we decided it must be coming from the attic, which had extra (white) insulation blown in after renovations were complete. We increased the HEPA filtration of the HVAC, with no results.  I checked for openings in the flexible ducts of the HVAC which could entrain insulation, with no results.  I tried several different times to seal the attic penetrations, which in actuality should have been done by a conscientious insulation company BEFORE the extra insulation was blown in.  I sprayed foam:

• Around the HVAC vents
• Around the bathroom exhaust fans
• Around the LED puck lights (must check with the lighting manufacturer before doing this as some lighting is incompatible with direct-contact insulation.  The light needs to be “IC rated” in order to safely come into contact with the insulation.)
• Around ceiling fan boxes
• Around hanging shelf penetrations through the drywall of a floor-to-ceiling closet

It took multiple trips to the attic (with a good dust mask, of course) and quite a few cans of spray foam to get the job done, but sealing these areas, and one other (big) thing really helped cut the dust down.  It wasn’t until I really analyzed what was propelling the dust from the attic into the living space, that I figured out what was going on.

We’ve written several articles about negative pressure in your home and its negative effects. (This one has an eye-opening video linked).  I suspected that the dust was coming from the attic because negative pressure was somehow being generated in the house by the HVAC system.  However, I didn’t look at the big picture.  The living space is adjacent to a woodshop where my father carves (his hobby) and he uses a powerful dust collector to whisk the dust out of the workshop to a drum container.  The motor on this dust collector is rated for 240V so you can imagine that it’s a heavy-duty machine and being situated in the carport, can be heard from some distance from the house.  This thing SUCKS, and most of the time he’s using it with the door and window closed, so where is the makeup air coming from?  The workshop shares a common wall with a small bedroom in the living area (see red circle in diagram below).  It’s not too big of a leap to think that the dust collector may be pulling air from the house, as well, which in turn draws air from the attic when the ceiling penetrations were not sealed. 

To seal the wall between the woodshop and living area, I caulked the baseboard to the floor, as well as sealed the electrical boxes by taking off the switchplate and sprayfoaming around them as much as the little foam straw would allow (extra large switch plates help if you have to cut out the drywall a little).  The drywall took care of the rest of the wall.

Sometimes it takes a bit of thought to figure out the air currents in your home, but they are well-worth investigating!  Recently I found (by accident) that some carpenters had terminated a whole-house vacuum system in the ceiling of their house instead of routing it outside.  Even though the system used a filter, the space above the tiled ceiling was thick with a fine dust. We only discovered it when a  leak forced replacement of part of the roof above it.  We extended the PVC vacuum exhaust pipe just a few more feet and ran it out through the soffit.  It just goes to show that a little investigation (and a lot of spray foam) can go a long way to maintaining less dust in the house! 

How do water-based vacuums work and are they better than traditional vacuum cleaners?

Do you like how fresh the air seems after a rainstorm?  Well, that is the effect of the rain “washing” dust and microbes out of the air.  Sure, on a hot summer’s day it’s not long until these contaminants return, but it’s a welcome respite.  It’s nature’s air purifier!

This brings us to the topic of water-based vacuum cleaners.  Mechanically, the suction part of the vacuum (with or without a rotary brush to dislodge dirt) is the same as traditional vacuum cleaners.  However, using water to “filter” dust out of the air stream is the main difference. 

Let’s talk about how filtration using water as a filter is different from filtration using other mechanical means, such as a cyclonic separator or filter.  When a stream of dirty air is filtered by water, the dirt or dust in the air gets wet and heavy, and thus becomes entrained in the water, leaving the air “clean” on exit.  However, most water-based vacuums also use HEPA filters, in order to prevent any remaining dust or dust in water droplets from leaving the machine.   These HEPA filters are designed to get wet, whereas non-water-based vacuums do not have filters that can get wet.  

In traditional vacuums, the incoming dirty air stream usually first passes through a vacuum bag or cyclone, which filters out larger particles of dirt and hair.   In bagless systems, the cyclone uses centrifugal force to “spin” out these large particles so that the user only has to empty a cup of dirt, not replace the bag.  Single-stage or multi-stage cyclones can be employed, where a multi-stage cyclone allows the vacuum to operate longer without losing suction.  After the bag or cyclone, a final filter (this is where the HEPA filter is found if the vacuum has one) filters out any remaining dust in the air stream before exhaust.

The attraction and “wow” factor of water-based vacuums usually lies in the dirty water that you empty from the vacuum after cleaning.  If the floor is cleaned with a traditional vacuum and then with a water-based vacuum, being able to “see” the dirt that’s left behind drives enthusiasm for the water-based vacuum.  No one cuts open the bag from their traditional vacuum after cleaning, so the satisfaction of seeing that dirty water makes one think that water-based vacuums provide superior cleaning power. 

Although we haven’t tested them, we thought we’d share some insight on the most common water-based vacuum brands and what their customers like and dislike about them. 

Rainbow Vacuum Cleaners

You may have heard of or viewed a Rainbow Vacuum Cleaner, the first vacuum to remove dust from its vacuum stream using water.  The manufacturer, RexAir, was formed in the 1920’s and has been improving the Rainbow ever since it was introduced in the 1950’s. (The Original Water-Based Cleaning System)  It relies on a rotating brush to dislodge dirt, and the suction power of the vacuum motor to bring it into the machine, where the filters purify the air before exhaust.  According to product literature, its unique water filtration system captures typical household dirt, while remaining microscopic particles are caught by the HEPA Neutralizer Filtration System. This two-stage filtration combination removes nearly 100% of dirt and contaminants.  The company uses a network of Independent Authorized Rainbow Distributors which demonstrate the product in homes and businesses, so it’s not sold online.  Purchase prices for these units are not published either, however, customers seem to verify that these vacuums are the most expensive on the market.  Devoted Rainbow customers seem to keep their vacuums for 15-20 years, so the price per vacuum may be a very good value.  The units weigh in at about 20 pounds and rely on smooth casters to roll through your home.  Rainbow is “Certified Asthma & Allergy Friendly” and AHAM Certified: The Association of Home Appliance Manufacturers (AHAM) certifies that the Rainbow is a proven air cleaner designed to reduce air pollutants that contribute to poor indoor air quality.  The weight of the E2 model is approximately 40 lbs and comes with an 8 year warranty.

Sirena vacuums ($600-990) are designed and made in Canada.  They can pick up wet or dry messes, and come with an assortment of tools to get into nearly every crevice.  The motor is quite powerful, providing ample suction, and the water reservoir hold 3.5 liters of water maximum, which is quite a lot of water in which to filter out dust and dirt.  It weighs 40 lbs and comes with a 10 year warranty.

Quantum X ($439) is an upright vacuum, meaning you don’t have to drag a canister around with you while you clean.  The power head can extend up to 18”, making it a good competitor to most canister vacuums, and it has a hose for smaller cleaning attachments.  The upright style affords less room for the water compartment, but this also allows it to be more portable.  It weighs 27.1 lbs. 

Kalorik Water Filtration Canister Vacuum Cleaner ($120) is a good budget cleaner made by a Belgian company that has been in business since 1930. Termed the “poor man’s Rainbow” by one reviewer, it’s a great option for those with pets and/or allergies, and it’s a lot lighter at 14.3 lbs.  The suction head does not have a rotating brush, but it has a high/low adjustment, very powerful suction, and picks up wet and dry messes. Without the rotating brush, it’s best suited for hard floors and not carpets.  It has a 1 year warranty.  

These four vacuums all use water as a filter, but are different from cleaners that vacuum and mop at the same time.  I use the CrossWave floor and area rug cleaner by Bissell ($257), which uses water to clean AND filter out dust.  For homes that have no wall-to-wall carpet or a lot of area rugs, these types of upright vacuums are convenient and ideal because they perform two functions at one time–vacuuming and mopping, with good efficiency (check out our article on using these types of vacuums to tackle dust in your home).

In all, many customers (including myself) prefer water-based vacuums over traditional ones because:

1. You can see the dirt they pull off your floors very readily when you empty the vacuum, which is both satisfying and disgusting.  Whether this is more than the dirt that is captured by traditional vacuums is not measured.

2. There’s no bag to retain smelly dirt (especially pet hair).  With traditional vacuums, this smelly dirt stays in your home until you replace the bag, and it also expels smelly air every time you vacuum until you replace the bag.  (As a pet owner, I appreciate this!)

3. There are no bags to purchase and replace! 

4. They are very good at retaining suction (most work until the suction compartment is completely clogged with debris or pet hair), and restoring suction is very easy to do–empty the compartment!

5. Many of these models remove wet or dry messes (traditional vacuums can only handle dry dirt). 

6. Many of these models allow addition of essential oils to the filter water or cleaning water for a fresh scent of your choice, and some, like the Rainbow and Sirena, double as air purifiers.

The “cons” of water-based vacuums are that: 

1. Of course, water is heavy and more quality construction can make the unit VERY heavy and bulky, to the point of not being mobile enough to clean separate floors in a home if you are physically challenged.  Most water-based models are “cannister” type instead of “upright” in order to more easily and stably move the water around.

2. Water-based vacuums can be more costly than traditional vacuums.

3. Some water-based vacuums (like the Bissell CrossWave) require a detergent to enhance cleaning of the floors.  This detergent is an added operating cost and can have toxic ingredients in it (unless you make your own, check out our recipe here). 

4. If your vacuum uses water to “scrub” and then suck up dirt and debris, water that stays on your floor can temporarily increase humidity in your home, albeit less than regular mopping.  If water is used to clean carpeting, you must be careful that it’s thoroughly dried, and quickly, so that mold doesn’t have a chance to take root.

Do you prefer another type of vacuum that we haven’t discussed?  Let us know!

What’s in a chemical filter?

Current events certainly stimulate a lot of research, and the accidental release of toxic chemicals from storage and transportation units is no exception.  When a dangerous chemical is odorless and colorless, how can we possibly protect ourselves and the air in our homes?  Enter chemical filters, which are actually already available for purchase.

Many gas filtration media start with a base material and then add (impregnate) the base material with specialized materials.  Since all of these base materials have a multitude of miniature holes that can get “plugged up” with dust, it’s best to make sure the dust filter is clean and in place to preserve the life of the chemical filter.  The base material is incredibly light because of the vast amount of internal surface area it has in its many cavities and holes.  The way these materials  purify air is called “adsorption” (in contrast to absorption).  Adsorption and absorption both “suck up” liquids or contaminants, but there is a difference:  a sponge will absorb water, but eventually the water leaks out or evaporates.  Activated carbon, activated alumina and zeolites adsorb certain chemicals, some including water, but the adsorbed liquid or gas does not escape because a chemical bond is made, until the material is regenerated with high heat.  Since adsorption is a surface phenomenon, good adsorbents are those having large surface areas per unit mass and high attractive forces for the compounds to be adsorbed, called the solute. Although all molecules are adsorbed to a certain extent, those having high polarity are likely to be more strongly adsorbed than those having low polarity. Since water is a highly polar material, it is much more strongly adsorbed than hydrocarbons, for instance. (Air and Gas Drying with Activated Alumina)

Here are the most common base materials:

A main ingredient in these filters is activated carbon.  We’ve written about it here but when you have something more dangerous than sweaty socks or cat litter smells, we like to dig a bit deeper on its capabilities and limitations.  Activated carbon removes volatile organic compounds (VOCs) and acid gasses, which make them useful against a wide variety of pollutants.  To review, VOCs are compounds that have a high vapor pressure and low water solubility.  They are natural and human-made chemicals that are used and produced in the manufacture of paints, pharmaceuticals, and refrigerants. (EPA.gov)  An acid gas is any gaseous compound which, when dissolved in water, will form an acidic solution.  Many industrial compounds are acid gasses, but did you know that we actually exhale an acid gas?  Carbon dioxide (CO2) is an acid gas, and activated carbon is a method for removing excess CO2 in a space.  

Activated alumina is another base.  It’s a porous, solid form of aluminum oxide, otherwise known as Al2O3 or alumina. This is the same mineral that makes up the precious gems ruby and sapphire, with impurities being the source of the stones’ bright colors. After activated alumina has been evacuated of existing moisture by heating it, the high surface area and many pores of the material allow for the uptake of water and other molecules through adsorption.  (What is Activated Alumina?) At about 1.5 to 3 times the cost of activated carbon, activated alumina is pricier but very attractive for adsorbing different chemicals.

Zeolites are another base material for chemical adsorbents.  They can be naturally occurring or man-made.  Zeolite has an aluminosilicate framework. Which simply means minerals composed of aluminum, silicon, and oxygen, plus countercations. This framework provides exceptional strength and stability to the honeycomb structure. It also makes it very difficult for the positively charged atoms (cations) to leach from Zeolite. (What is Zeolite?)   Molecular sieves are a type of zeolite that are manufactured to precise frameworks and pore sizes for specific applications.

Now that you know some of the base materials, additives (also called “doping”) can enhance capture/filtration of specific contaminants.  

• Potassium Permanganate is added when sulfurous compounds may be present (such as hydrogen sulfide and sulfur dioxide).   According to this filter company, their molecular sieve impregnated with potassium permanganate oxidizes gaseous pollutants such as hydrogen sulfide, sulfur dioxide, formaldehyde, ethylene, mercaptans, and various aldehydes and alcohols.   Do you know what mercaptans are?  They are the sulfurous, rotten-egg smelling additives that are added to natural gas to help you know that there is a leak.

• Potassium Iodide:  some AustinAir filters are impregnated with potassium iodide, for increased removal of formaldehyde and ammonia.  They are best used in places like new homes, laboratories, beauty salons, funeral homes, etc. Sources of formaldehyde in homes can be carpets, wood panel, construction materials and furniture upholstery, if not an outright chemical leak. (achooallergy.com)

• Magnesium Dioxide and Copper Oxide: The air filter company Blueair adds these compounds in their activated carbon filters to remove carbon monoxide, ethylene oxide, and ozone.

So which filter is best for me?  It’s hard to plan for every scenario, but you may take into consideration the following:

• This article/table by the California Air Resource Board (CARB) in response to the Aliso Canyon gas leak (California, 2015) describes what types of filters are in a number of high-end air purifiers.  The models may have changed slightly but it can give you an idea of how air purifiers can be used to reduce specific chemicals (mercaptans were judged to be the source of most peoples’ health issues).

• If you live very close to a refinery or manufacturer of specific chemical products, you may want to find out what chemicals they manufacture, store and load, what VOCs/fumes are produced and what air filter is best to remove those VOCs. 

• If you are interested in a particular type of filter, look for (or ask for) test data that verifies it removes what it’s designed to remove.  In an MIT study of 4 consumer-grade air cleaners, only 2 of them removed the VOCs toluene and limonene effectively.  

• In the case of radon, activated carbon filters (and the others mentioned above) will not adsorb radon gas, but they will adsorb most of the radon decay products (termed “radon daughters or progeny”), which are actually the source of health issues associated with radon. (Reduction of Radon Working Level by a Room Air Cleaner).   Therefore, activated carbon is not recommended for first-line defense against radon infiltration into your home; a venting system is more appropriate and you should contact a professional if you have radon in your home.

• In the end, activated carbon is widely used for a reason: it removes a lot of VOCs!  If you don’t have a specific chemical that you’re concerned about, this type of filter is a readily available, broad spectrum weapon against many pollutants.  If your air is particularly dusty, you’ll want to make sure that it also has a HEPA pre-filter to protect the activated carbon from getting clogged with dust.

The benefits of living upwind

I can only think of a few times where being downwind was preferable.  If you’re a hunter, you’d want to be downwind of your prey so it won’t smell you and run away.  I didn’t mind being downwind of the coffee roasting plant when I lived in New Orleans because of the good smells.  In all other cases (maybe I’m missing one?), being upwind is the place to be. 

In several articles we’ve described the ways that nanoparticles and pollution can infiltrate our homes, and the effects that it has on our health.  Therefore, we advocate for “living upwind” of the many potential pollution sources in our cities and country today.  It’s just fresher, cleaner, and healthier.  Here are some reasons why:

• Major cities: many of the world’s largest cities (including London, Paris, New York, Toronto, Bristol, Manchester, Oxford, Glasgow, Helsinki and Casablanca)  have poorer “east ends” because the prevailing winds blow pollution from west to east. (study)

• Fossil-fuel power plants:  In a study surrounding a coal-fired power plant located in Pennsylvania, it was found that infants born to mothers living as far as 20 to 30 miles downwind from the power plant were 6.5% more likely to be born with a low birth weight (i.e., birth weight below 2,500 grams) and 17.12% more likely to be born with a very low birth weight (i.e., birth weight below 1,500 grams).

• Refineries and oil wells:  In 2020, 13 refineries in the US released benzene, a cancer-causing toxin, in amounts above EPA action levels.  (environmentalintegrity.org).  Unfortunately refineries have emergency releases of chemicals at various times, sometimes just because of a power failure.   In our post on emissions from oil wells, we reported that harmful VOCs and particulates are being released continually, and these increase the risk of respiratory and other illnesses.  

• Ports and airports: The California Air Resources Board (CARB) estimates that there are 3,700 premature deaths per year directly attributed to the ports and goods movement activities statewide and approximately 120 deaths per year associated with diesel particulate matter emissions from activities at the Port of Los Angeles and Long Beach. The economic cost associated with these deaths as well as for medical care for illnesses and missed school and work days is an estimated $30 billion annually. (The Impact Project, 2012 paper).  Noise and light pollution are also results of living near a port.

• Major highways: there are “statistically and economically significant effects of exposure to near-roadway pollution on mortality amongst the elderly” according to one study, however the pollution is also harmful to people of all ages, such as young children, who are susceptible to asthma, and adults, becasue exposure to fine particulate matter is associated with high symptoms of anxiety and antidepressant use. (discoverymagazine.com)

• Volcanoes: volcanic vents can emit gasses on an ongoing basis that contain toxic components such as sulfur dioxide (SO2: smells like a struck match or fireworks), hydrogen sulfide (H2S: smells like rotten eggs), hydrogen fluoride and hydrogen chloride (HFl and HCl, smell strong, irritating and pungent), and carbon dioxide and radon, which are odorless but also dangerous. (International Volcanic Health Hazard Network)

What if you can’t live upwind?  Then try to employ some techniques to prevent the outside pollutants from penetrating your home:

• Mitigate the stack effect by sealing the building envelope.  Contrary to popular opinion, just adding more insulation will not stop air leaks, because they are propelled by air pressure differentials, not just temperature differentials.  Pressurized will find a way through insulation if there is a leak in the building envelope.

• Make green your favorite color!  When possible, surround yourself and your property in trees and/or plants because they absorb VOCs and particulates, and create a myriad of health benefits for your mind and body.

• A 2011 study entitled “Improving Health in Communities near Highways” hosted by Tufts University suggested filtration as the number one method to reduce ultra-fine particles indoors.  Filters for residences and schools near busy roadways should be Minimum Efficiency Reporting Value (MERV) 14 or above, mainly because the ultrafine particle removal efficiencies of filters with lower MERV ratings are not reported.  Another method was to relocate building intake air vents to the downwind side of the building.  

• Bipolar ionizers like The Whole-Home Polar Ionizer, Germ Defenders and Air Angels  cause small nanoparticles to stick together and drop out of the air, to help you avoid breathing them in.