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A Clean-Air Kitchen Checklist

A Clean-Air Kitchen Checklist

It’s clear from the amount of money and size of kitchens nowadays that the kitchen is where people spend a lot of time.  Big islands, comfortable chairs and features like coffee bars and wine coolers make it easy to stay and chat while the host cooks up a delicious meal.  The problem is that some things get overlooked in kitchen design and maintenance, so that hidden appliances may be making your air dirtier than your guests would expect! 

Kitchen exhaust vent

We’ve previously posted about how cooking and baking can raise fine particulates and VOCs in your kitchen to levels of a polluted city.  The best defense against spreading them to the rest of the home and breathing them in is to use your kitchen exhaust vent.  The problem is that the exhaust vent filter is often overlooked, and a clogged filter strains the vent motor and can throw particles right back into your kitchen.  Here’s where it’s important to a) check whether your vent is recirculating or exhausting to the outside, and b) clean the filter!

When I first learned about combination microwave/vent hoods, I thought, these are space-saving genius.  Being a moderately tall person, I could easily lift items in and out of the microwave, the unit was not taking up any counter space, and it doubled as a stove vent hood.  However, the more I used the one in my current home, the more disappointed I was with it.  Here are the problems with most microwave/vent hood combos:

  • The ventilation can exhaust directly back into the kitchen.  That’s right, those little grilles above the microwave door are the exit point of the exhaust fumes, which don’t get a lot of filtering before they come straight back into the kitchen.  The other option is to exhaust outside, which is far better.
  • Microwave/vent hood combos typically do not provide the cubic feet per minute (cfm) ventilation that a standard size kitchen requires, and what little you get can be further reduced if there is more than one turn in the ductwork above the unit to the outdoors.  
  • Although it’s a common situation, placing the microwave on a countertop is not a great installation either, because cooking gasses generated in the microwave are vented directly into the kitchen with no filter. 

Here’s what we recommend to get the cleanest air while you cook:

  1. If you have a combination microwave/vent hood, check two things:
    1. Does the vent hood provide the correct cfm for your kitchen?  Here is an article to help you calculate whether it’s sufficient for your kitchen.  If you don’t know the cfm of your unit, type the model number into an internet search.  If your unit does not have the necessary throughput, consider placing the microwave elsewhere and getting a more powerful standalone vent hood.  In this case proceed to #2.
    2. If the cfm is sufficient, does the microwave/vent hood exhaust back into the kitchen?  Place a microwaveable container in the microwave with some water and start to heat it.  Place your hand over the grille above the door and see if you can feel a stream of air moving into the room.  
      1. If so, then the exhaust is probably set to exhaust into the kitchen.  If you own your home and you want to change it to exhaust outside, it’s possible to take the microwave down from the wall and change the exhaust configuration.  Here’s a short video on how to rotate the blower fan of the microwave, which will change the exhaust port configuration.  This change necessitates installing a duct above the microwave and vent port outside, however.  For the venting, check this video
      2. If you are renting or otherwise can’t change the configuration of your microwave/vent hood exhaust to outside, then do your best to clean the filter on a regular basis so that cooking particulates can be trapped before they’re blown back into the room.
  2. Congratulations if you are upgrading to a standalone vent hood (our choice for the best kitchen atmosphere)!  Here are some tips to split up the microwave and vent hood and make each perform well.
    1. If budget is not a constraint, vent hoods now come in a “balanced” option, which means they not only suck fumes from your kitchen, but these are replaced with fresh air from outside.  Check out this smoke test on such a unit. 
    2. For normal budgets, good kitchen vent hoods can be purchased between $200-500 (here is a great review on the newest models, but be sure to pick one that vents externally!)  In addition to capacity, it’s also wise to get the quietest fan you can afford so that you won’t be annoyed with the sound.
    3. Now, where shall we place the microwave?  Most kitchen design professionals are happy to place it anywhere in the kitchen except the countertop, but then venting it back into the room is still polluting your indoor air.  Besides the moisture emitted from cooking steamy foods like rice or potatoes, some foods emit a lot of ultra-fine particles (UFPs).  Popcorn is one of these; in this study it was discovered that UFPs and PM2.5 generated by microwaving popcorn were 150-560 and 350-800 times higher than the emissions from microwaving water, respectively. About 90% of the total particles emitted were in the ultrafine size range.  To avoid releasing these harmful particles into your kitchen, here are the best scenarios for venting the microwave.
      1. Install it in cabinetry with a dedicated vent to the outdoors.  No questions about getting the vapors out in this case!
      2. Install it in a lower cabinet space next to the stove.  That way, steam and UFPs exhausting from the top of the unit can be drawn up and out by the range hood. “Drawer” microwaves are becoming more popular now (see photo below). 
      3. (Least effective, but still possible) Set the microwave on the counter next to the range hood but 2 feet away from it, for heat safety concerns. 

The last two options require manually turning on the range hood every time you use the microwave, but if you have a nice quiet vent hood, this shouldn’t be a problem.  

Microwave Drawer installed next to the oven/stove (source: Home Depot)

Refrigerator coils

It’s pretty obvious when the refrigerator needs cleaning: food spills inside and dirty fingerprints outside get the most attention.  However, the most important part (the working “guts” of the fridge) is easy to overlook, except for some dust gathering on the toe kick grill.  On most newer models, the cooling coils are hidden under the fridge, and all kinds of dust (especially if you have a shedding pet) will gather there and clog up the vital cooling parts. The coils should be cleaned every six months to one year to keep the fridge working properly, and keep the accumulated dust out of your air. Here’s how to clean it without a lot of hassle (

  • If the coils are not exposed at the back of the unit, then remove the toe kick panel in the bottom front to expose them.
  • Use a vacuum cleaner with HEPA filter (you don’t want to blow that dust back into the air) to vacuum off as much dust as you can reach.
  • Use a coil cleaning brush to get between the rows of coils, keeping your running vacuum nearby to suck up dislodged dust. 
  • Clean off the front grille with the vacuum and soap and water if necessary, and reinstall it.

The Dishwasher

Ahh, the dishwasher–what a super-convenient place to hide dirty dishes.  My cousin (an engineer) always joked that in his new house, he’s going to install 2-3 dishwashers and no cabinets.  Why?  Dishwashers are way cheaper than cabinets and no one likes to unload the dishwasher.  When you can have 1 “clean” and 1 “dirty” dishwasher at all times, you can take clean dishes from the clean one, use them and place them in the dirty one, and theoretically no cabinets are needed!  Somehow, I think his wife will have a problem with no cabinets…

Back on topic, dishwashers are appliances that use steaming hot water and caustic detergent, but are not vented to the outside.  Where does all that steam and vaporized detergent go?  Into your kitchen air, of course!  Hayward Score is a company which identifies the major issues in your home that can impact your health and gives you free personalized actionable recommendations to fix them.  They performed a study on how bad dishwashers are for your indoor air quality, and found out that it was really the “heat and dry” cycles, not the soap, that caused air quality problems.  They placed an air quality monitor in the room adjacent to the kitchen and ran the dishwasher three times:

  • Dishwasher run with standard soap, heat and dry cycle on = Air Quality: RED ZONE (bad)
  • Dishwasher run with no soap, heat and dry cycle on = Air Quality: RED ZONE (bad)
  • Dishwasher run with standard soap, heat and dry cycle off = Air Quality: BLUE ZONE (good)

Based on these results, the soap was not causing elevated levels of VOCs but high temperature combined with chlorinated water was.

When your home is supplied by city or community water, these systems typically use a lot of chlorine to keep bacteria out.  I mean, A LOT–often you can turn on the tap and it will smell like a swimming pool coming out of your faucet.  Heat and dry cycles can reach temperatures of 160 deg F or more, which when contacting chlorinated water, produces chloroform.  The chloroform can drift through your home farther than the steam does, hence the bad air quality readings taken in the next room. 

The solution to good air quality while running your dishwasher?  If your tap water is sufficiently hot to sterilize (above 120 deg F), then don’t use the heat and dry cycle settings.  Also, run your kitchen exhaust vent during and 30 minutes after the dishwasher cycle, to move steam and any other gasses outdoors.  If your tap water is below 120 deg F, then it’s a good idea to use the heat cycles to make sure everything is sanitized, but make sure to run the kitchen exhaust vent simultaneously.

Toasters, Crock Pots, Air-Fryers, Electric Skillets and all their cousins

We have a lot of miscellaneous appliances hidden in the cabinets or sitting on the countertops, which can put a lot of fine particulates and VOCs into the air when using them.  Toasters are one of the worst offenders, and start emitting toxic fumes from the moment you turn them on (University of Texas at Austin study), because they are heating up the leftover bits from previous foods, including oils.  Toasting two slices of bread caused twice as much air pollution as is seen in London for 15 to 20 minutes – meaning three times the World Health Organization’s safety limit. (  The solution?  Set them as close as possible to your range (2 feet away is safe if you are using the range also) and fire up that kitchen exhaust fan.  Heck, chopping your onions next to the kitchen exhaust fan can even whisk away the chemical irritant that they release to make you cry (syn-Propanethial-S-oxide).

With a good exhaust fan and little cleaning you can spend as much time as you like in your kitchen without worrying about what’s floating around in the air! 

Photo by Jimmy Dean on Unsplash

Navigating Electromagnetic Frequency (EMF) Radiation

Navigating Electromagnetic Frequency (EMF) Radiation

Convenience and technology go hand in hand.  If you want to save money at your store, the store’s “app” gives you the deals straight to your cellphone.  Smart doorbells and smart thermostats keep us safe and comfortable.  Baby monitors and cameras help us to keep an eye on the kids.  What could be better than knowing and doing more than your parents ever could?

The only problem with these perks is the energy they emit while helping you.  It’s called electromagnetic frequency radiation, or EMF for short.  Now, don’t get me wrong.  Anything that uses electricity, even a washing machine motor from the 1960’s, will have an electricmagnetic field associated with it, because that’s what electricity does.  Electrons move inside the electric supply cord, back and forth at the rate of about 60 cycles per second (60 hertz) in the US.  When the motor is energized, the electrons moving through the coils of the motor generate an electric field that spins the drum, and another motor that pumps out the water.  Electricity is right up there with indoor plumbing as something we wouldn’t want to be without!  

There is a big difference, however, between the way an old washing machine and a new cellphone use electricity and emit radiation.  The old washing machine had two modes, on and off, and it used power straight from the wall (110-120 volts alternating current, 60 hertz) with no transformers, inverters or rectifiers involved.   The cellphone, however, could never be plugged into the wall because it uses low voltage (12 volts) and “direct current” (DC).  The charger is plugged into the wall to convert high AC to low DC voltage to feed it to the sensitive electronics of the phone.  The phone, once charged, is essentially a battery with several different modes and the ability to radiate signals in a radius around it (about 30 feet for Bluetooth).  This generates two different problems with it: the way the charger manipulates electricity (taking the AC and converting it to DC and lowering the voltage) and the way both the charger and cellphone emit radiation.

“Dirty electricity” is admittedly not easy to understand.  After all, electricity is promoted to be the world’s cleanest energy, right?  We are enticed to replace everything that emits carbon with newer appliances that are “greener” for the planet with “no” emissions.   Yet, there is no such thing as free.  There are trade-offs for every convenience and savings in the pocket don’t always mean a savings to our peace of mind or health.

Since dirty electricity can’t be seen, smelled or touched, the best way to describe it is in pictures.   The photo below is of an alternating current electrical signal.  (If you don’t understand the difference between alternating and direct current, here is a really good video). The bright green line is clean power, which in alternating current is a smooth rolling sine wave (the peaks and valleys occur 60 times per minute, hence 60 hertz).  The green fuzz is dirty electricity, which is made up of jagged spikes that cause more radiation and can cause damage to equipment.  Where does the green fuzz come from?

Source: What is Dirty Electricity?

The green fuzz, or dirty power, is what is left over when you convert AC into DC or maneuver it in other ways.  Here is a video that visualizes what the little transformer/rectifiers on your cellphone charger and laptop chargers are doing to convert the power from the wall (120 volts AC) into usable power for your device (12 volts DC).  Chopping up the signal and smoothing it out causes some power “noise” and energy wastage.  Have you ever felt the transformer plug of the phone, or of your laptop computer?  Heat is another sign that there is energy being wasted.  

The green fuzz is not just ruining a nice picture of a sine wave.  The spikes and unpredictable energy can cause damage to electronics as well as to our bodies.  Dirty electricity can cause the following health issues (What is Dirty Electricity?) :

  • Headaches

  • Sleep Disturbances

  • Fatigue

  • Tinnitus

  • Cognitive Impairment

  • Heart Arrhythmia

  • Mood Swings

  • Weakening of the nervous, endocrine and immune systems

  • Increased risk of serious chronic illnesses such as cancer

Why does dirty electricity affect us?  Because we, as humans, run on electricity too.  The nervous system that regulates many functions in our bodies is electrical, and its sensitive equipment and signals can be affected by outside electromagnetic radiation.  For example, scientists have known for a while that some types of EMF radiation can actually cause bone to grow, and calcium channel blockers (which are frequently prescribed for heart arrhythmias) block EMF effects because they block electrical activity in the body. (Electromagnetic fields act via activation of voltage-gated calcium channels to produce beneficial or adverse effects)

Many health effects are only manifested when a major change occurs, like the installation of a smart meter on our home, or a newly installed cellphone tower coming online nearby, or moving into an apartment with wi-fi signals surrounding yours.  However, symptoms can also be gradual as well.  Like the effects of mold and mycotoxins, EMF radiation seems to affect those who are most sensitive to them.  When most of the population are not affected outwardly, regulation of new and more profuse radiation is not a priority.  However, quantified effects on our microbiology such as blood, organs and DNA through research should be enough to increase awareness of its dangers.

Although governments and health organizations (including the WHO) have denied that there is any risk to our health from dirty electricity, here is a short list of studies that have shown there is a cause and effect.  Since animals are even more sensitive than humans (termed “canaries”), included are a couple of real-world case studies on how EMF has affected farm animals, with detrimental effects on their behavior, output and reproduction.

The good news is that you can take control in your own home and eliminate some causes of dirty electricity.  Dimmer switches and compact fluorescent bulbs (CFLs) are some of the worst offenders, so try to eliminate these in your home.  Unplug computer and cellphone chargers whenever they are not in use, and when they are in use, keep them as far from you as possible.  

Other sources of EMF radiation can be controlled as well: 

  • Smart meters: Smart meters are power meters that broadcast a signal similar to your cellphone, to the electric company so that they can monitor power usage remotely.  Although many utility companies claim that their meters only “broadcast” less than a minute per day, the pulses sent by the meter (typically 3 milliseconds each) can be over 10,000 times per day.  (Frequently Asked Questions about Smart Meters)  If you can, opt out of having a smart meter placed on your building and have it replaced with an analog meter.  If you cannot, there are meter cages available that can significantly block EMF radiation from the meter.  This video shows how high and frequently EMF radiation can be emitted from Smart Meters.

  • Wireless routers: Unplug wireless routers at night and place them away from bedrooms or areas where people spend extended periods of time.  

  • Baby Monitors: Research the baby monitor you use to see whether it is safe, and place it a safe distance from the crib or bed.  

  • Cellphones: Restrict cellphone use by children and for adults, opt to use headsets or  speakerphone as often as possible, carrying the phone in a purse or away from your body.  

  • Solar power inverters:  the process of converting low-voltage direct current into high voltage alternating current produces dirty electricity, which can build up over time to dangerous levels inside your home.

There are two types of devices that can detect EMF radiation: a Graham-Stetzer meter that measures dirty electricity in GS units (I’ll discuss this next), OR simply an AM radio!  AM radios can pick up low-order harmonics.  Tune it down to the lowest amplitude, about 500 kHz, to start, and turn up the volume a bit to hear the static.  Bring it near a possible EMF emitter like a cellphone or its charger plug, and listen for an increase in static or “ticks” to indicate it is emitting EMF radiation.  You can also tune the amplitude up to its highest, to about 1600 kHz, to see what’s going on there.  (This setting is better for “hearing” the EMF from your cellphone, which typically broadcasts on even higher frequencies).  This video shows how to use an AM radio inside your home to detect relative volumes of EMF radiation from different appliances (the dimmer switch really puts out a lot)!  Another video shows you how to detect whether EMF radiation is coming from the line power (from the power company), or from the devices, like lighting and electronics, in your house.  

If you find you have a lot of EMF radiation with the AM radio, then you might want to invest in a more quantitative meter that shows the real levels of radiation.  With a meter designed to detect EMF radiation, you can walk around your home to measure these levels.  The original meter, called a Graham-Stetzer Microsurge meter (after its inventors) measures EMF radiation in units of “GS”.  According to Dave Stetzer, a GS unit is a measure of the energy on electrical wires generated by high frequency transients and harmonics, and is influenced by voltage, amplitude and frequency. (presentation by Dr. Magda Havas, PhD).  According to one electrician, under 200 GS is good and acceptable, but Dr. Havas has noted that those who are more sensitive and already have health issues like diabetics and multiple sclerosis patients, require readings under 40 GS.  In order to reduce EMF, a “Stetzerizer filter” can simply be plugged into any normal electrical outlet.  This video shows how to use a Graham-Stetzer meter and Stetzerizer filters to get rid of dirty electricity.  After removing as many offending appliances as possible like dimmer switches, CFL bulbs and unused electronic charges, the filters are very easy to use–just plug them in! 

If you have unexplained or chronic health issues, it’s worth exploring and measuring EMF radiation in your home.  This type of pollution can’t be seen, smelled or heard but the health effects on many people are debilitating, and intervention can provide significant relief.  We hope you will do your own research on EMF radiation!

The Not-So-Silent Killer: Roads and Highways

The Not-So-Silent Killer: Roads and Highways

Even with the shift towards the ability to work from home, some jobs require proximity to cities, which cause people to live in places adverse to their health.  In a recently published study from the University of Leicester in the UK, researchers identified that road noise, such as the rumble of engines, honking and braking, causes hypertension (increase in blood pressure).  The study reviewed the status of 240,000 people over 8 years and looked at the correlation between the noise of where they lived (using addresses and computer modeling tools) and their blood pressure.  It also adjusted for air pollution, because we know that fine particulates and nitrogen dioxide can also have effects on blood pressure.  It turns out that plain old traffic noise was enough to cause an increase in hypertension, even though those who are also exposed to more air pollution had the highest risk.  

Ok, so what do you do if your housing choices put you squarely in traffic central?  

Consider where the noise comes in the most, and try one or more solutions for that area, which may be enough to dampen most of the sound coming in.

Windows on an outside wall facing a busy street will certainly be the source of most of the noise, and there are several ways to block out most of it.  Single pane windows are very noise-transmissive, and double pane are a bit better, but each of them can be improved significantly with custom window inserts like those offered by Indow.  If you are a renter or don’t own your house, replacement windows are likely out of the picture, and more expensive than these inserts.  The company can provide a laser measuring system if you’re unsure about the squareness of your windows (for older homes), and once fabricated, Indows can easily be installed by one person (or two people for a large window).  The compression fit keeps them snugly in place to block sound.  

If you are not inclined to pay for window inserts, you can make your own foam board inserts to sleep soundly at night when the window’s not needed!  Just pick up a large sheet of foam board and measure and cut it carefully to the exact measurements of your window casing, attaching handles/pulls to the top and bottom of the inserts to help you install or remove them.  They can be stored in a closet, or behind long drapes during the day when they are not needed.

If you don’t want the expense of window inserts, acoustic caulk may help.  You’ll want to remove the existing caulk and replace it with the acoustic caulk.  It’s not a quick job, but if your windows are older and haven’t been caulked in a while, it will also provide needed thermal sealing too.

Thick, heavy curtains like these are much easier to install than caulk, come in a variety of colors, and are specifically made to block noise.  

Plants need light, so placing them near a window will benefit them and you–they can also absorb noise!  Plants with thick foliage and fleshy leaves are the best at absorbing and deflecting it.  This article lists a  number of plants in different styles and heights that can be placed on the floor, on stands or hung from the ceiling to deaden sound.  As a plus, some plants also absorb VOCs that can seep in around the windows from the vehicles outside.  Areca palms, rubber plants, Dracaena (Janet Craig variety), ferns and  peace lilies are common to both of these lists!

A few more Tips for Dealing with Noise from the Street can help for walls that face the street:

  • Bookcases with lots of books

  • Portable closets like armoires

  • Hang a thick tapestry or quilt as a statement piece on the wall

  • Hang large or small art canvases with the backs filled with foam board

And finally, all the other places that sound can enter and bounce around your space:

  • Add thick, cushy rugs (if you have the ability to keep them clean, of course!)

  • Install door sweeps/seals (many are easy to install with adhesive or slip-on type)

  • Add a thick curtain with retractable rod if you have an entrance hall that emits noise

  • If you like music or audio books, try listening to them with sound-canceling headphones to have a studio-feel while relaxing, working out, cleaning or just walking around.

For tips to get a more restful night’s sleep, check out our post on Maximizing Your Sleep.   We want you to have the healthiest home possible, so whatever you can do to reduce outside noise in your space will be worth it, for your heart and for your mind!

Photo by Josh Eckstein on Unsplash

Which DIY mold test kit should I get?

Which DIY mold test kit should I get?

Every home has some mold, because mold spores practically hitchhike into the home on our clothing, groceries, and even the air.  The difference between acceptable levels of mold and an infestation, however, is whether the moisture and food sources exist to feed an infestation.  There are many reasons to test your home for unacceptable levels of mold, some of which are:

  • Musty smells in an area

  • Recent flooding in or around your home

  • Roof damage

  • Renovations like roof, siding or foundation repair that expose your home to the elements

  • Mysterious health issues in any resident of your home

If you suspect an infestation of mold in your home, there’s no time to waste in testing, stopping the growth and removing the mold!  The health effects of living with a mold infestation are too costly not to do anything! 

Of course, if you have the resources and are able to hire a trained, reputable mold inspection and remediation company, they are often preferable to DIY kits because these inspectors have the training and equipment to make a thorough inspection and testing of your home.  However, working on a budget often means if you spend too much on inspection, there isn’t enough money to make a thorough remediation.  We get it, and so do makers of DIY mold testing kits.  For this reason, we have investigated some DIY kits and even partnered with one. 

There are several types of DIY mold testing you can do in your home.  Here is a description of each, from lowest to highest costs:

  • Gravity plates (also commonly called petri dishes)--an Air Sampling method:  When opening a sealed petri dish to the air in your home, mold spores in the air land on the sugar coating (agar) lining the dish and start to grow.  This method does grow mold!  However, unless you get your samples analyzed by a lab, you will not know for sure what species of mold is present, and even then, only “relative” quantities of mold colonies can be inferred.  If you decide to go this route, we recommend Micro Balance Health Products’ EC3 Mold Screening Test Kit - 6 Pack, which retails for $36.  It has detailed, easy to follow instructions to determine a relative “mold burden” in your home, but does not include the option to have your samples analyzed by a lab.  Because it’s sold by a company that has developed several mold abatement products and  many more highly reviewed health supplement products, you can be sure that they are interested in your best health!

  • Spore traps–an Air Sampling Method: GotMold combines the best of professional technology with DIY convenience.  Although it’s a major step-up in pricing from agar plates (a 3-room kit is $299 including return shipping and analysis), you can use the same sampling procedure that professionals use, and professional lab analysis is included in that package.  Their patented BioVac™ Air Sampler can be reused, so if you decide you’d like to retest after completing renovations to make sure the mold is gone (wise idea), you can get refill “cassettes” to use with your machine (again, postage and analysis is included in the cost of the cassettes).  In the lab report, each area tested will be grouped under the following severity of mold: 

    • GREEN — Not Evident

    • YELLOW — Slightly Evident

    • ORANGE — Moderately Evident

    • RED — Significantly Evident

Then, you’ll get spore counts from 4 common and 14 other types of mold, as well as an indication of whether these molds are usually found with water damage.  It gives “next step” recommendations in the conclusion of the report.

  • Immunolytics’ Kit–Combination Air and Swab sampling method: Since not all types of mold reveal themselves in an air sample, Immunolytics offers a Quickstart Kit ($198) made up of gravity plates and 1 swab or “Build Your Own” kit ($33 per sample) that combines the two methods. Like Micro Balance Health Products’ kit, gravity plates are interpreted by number of colonies formed, and swab samples give a percentage of specific molds found in the sample.  You can also ask for a consultation to determine the next steps for your home. 

  • EMMA–Air or Swab sampling method:  Offered by RealTime Labs, This method is VERY simple in that you use the provided swabs or gauze, or cut out a section of your home’s AC filter.  The separate samples can be combined into 1 sample, or charged as separate samples. This test is ideal for homeowners who are already experiencing mold-related illness symptoms, as their “combo” tests not only test your home for 12 of the most common molds, but also detect 5 of the most common mycotoxins (mycotoxins are responsible for illness).  Knowing the mycotoxins floating around your home may help you develop a treatment plan with your doctor, and the company also offers urine tests, pet tests, and tests for other known toxins.  One disadvantage of this method is that combination of samples will not allow you to learn where the mold is coming from (which room has the highest count).  Check out our article “What’s the Difference between EMMA and ERMI?” to learn more about EMMA.  

  • HERTSMI-2–Dust sampling method:  ERMI was a test developed for research purposes by the US government.  Although it can tell you the presence of specific molds, it is unreliable for determining whether a building is safe to re-enter after remediation.  HERTSMI-2 is a method of interpreting the results of ERMI that is much more reliable (for mold scores less than 10) of whether you will get sick again when returning to a water-damaged building (WDB). HERTSMI-2 analyzes the results for 5 specific molds, also called the “Big 5”, which are most likely to cause relapse of symptoms for patients.  EnvironBiomics offers a very reasonable price ($130) and fast service for HERTSMI-2.  They also offer separate tests for endotoxins (bacterial toxins) and actino microbes (gram-positive bacteria), which are not common to be tested (see our article here about endo-and exotoxins).  If your home was heavily water-damaged or had water damage in multiple areas, you may want to opt for a HERTSMI-2 to make sure it’s safe to inhabit after the remediation.

Since the unconditioned outdoors has its own mold biome, it’s a  helpful baseline to reference.  Most tests do not suggest taking an outdoor sample, but GotMold includes one air cassette specifically for the outdoors in each of their kits.  That way, you can see the types and concentrations of mold directly outside your home, which may be influencing your indoor scores.  We have chosen to partner with this company because of the owner’s passion for helping average homeowners detect mold in an economical way (read his personal story and the company’s philosophy here).  Their air sampler was one of the first affordable machines for DIY air sampling.   

Of course, there are many more test kits out there, but be sure to do your research!  Some have extra fees for lab analysis, postage, or consultation, and each lab report reveals different information.  Companies started by physicians (like Realtime Lab or are even more helpful because they have taken the time to screen and affiliate with doctors around the US who can physically treat homeowners and their families who have been affected by mold.  Whichever method you choose, don’t stop looking for the source of mold in your home and remediation of the damage until retesting comes back with an acceptable score.  Even then, “acceptable” to one person may cause relapse in someone whose health has been severely impacted by mold.   Mold can be sneaky and hard to find, so if DIY tests don’t reveal the problem, check out our articles on Taking our Homes Back from Mold and article on How to Choose a Mold Remediation Contractor (which also speaks about inspection) to partner with professionals.  We at HypoAir are also available to help with products that can help keep mold at bay while you're remediating or on a maintenance basis. 

7 Ways Air Quality Impacts Our Skin Health

7 Ways Air Quality Impacts Our Skin Health

Pollution is not only harmful to internal organs: it can also damage the body's surface. Here is the connection between air quality and skin health.

While we often think of air pollution as affecting our respiratory system, its effects go beyond our lungs. It can also be detrimental to other organs.  The skin is the largest organ in our body and serves as a protective barrier against external factors such as pollution, UV radiation, and other environmental stressors. However, when exposed to poor air, the body's ability to protect itself can be compromised, leading to many problems. From dryness and premature aging to acne and eczema — air quality impacts skin health in a big way.  Below, we will analyze the seven most common ways air quality impacts skin health.

1. Dryness: making the skin dry, flaky, and itchy

Poor air quality can have a significant impact on the skin's natural oil, leading to dryness, flakiness, and itchiness. Particulate matter such as PM2.5, can penetrate the layers of the epidermis, causing oxidative stress and inflammation that disrupts natural oil production. Indoor pollutants, like smoke and volatile organic compounds for example, can also contribute to skin dryness and other issues.

It is essential to take protective measures against the detrimental effects of poor air quality on the skin's natural oils. This includes using a gentle cleanser, moisturizing regularly, avoiding heavily polluted areas, and using a humidifier when necessary to add moisture back into the air, so that relative humidity stays between 40-60%.

2. Premature aging: the destruction of collagen and elastin

Exposure to these same pollutants can break down collagen and elastin, proteins that give the epidermis its firmness. When these compounds are destroyed, skin can become saggy, loose, and more prone to wrinkles. Moreover, exposure to ultraviolet radiation, especially in polluted areas, only exacerbates this process.

To safeguard yourself from contaminants and UV rays, you should utilize protective clothing, apply sunscreen, and stay away from places with high levels of air pollution for extended periods.

3. Acne: clogging pores and causing inflammation

Pollution affects the appearance of our skin on the surface and changes it underneath. Inflammatory acne, characterized by red, swollen pimples, is particularly sensitive to air quality. Environmental contaminants, such as tobacco smoke, clog pores and irritate, leading to inflammation and blemishes.

Keeping up with a consistent skincare regimen that involves cleansing, exfoliating, and moisturizing is crucial in countering the harmful impacts of air pollution on the skin.

4. Pigmentation: affecting melanin production

Harmful substances from polluted air can penetrate the skin and stimulate melanin production, the pigment that gives skin its color. Increased melanin can lead to dark spots and blemishes on the body. These pigmentation problems can be more pronounced on skin areas that are frequently exposed, such as the face and hands.

Ultraviolet radiation can contribute to pigmentation issues, the intensity of which decreases depending on air quality.  It can lead to a harmful and uneven tan.

5. Eczema: irritating and exacerbating diseases

Eczema, a chronic inflammatory skin condition, can be particularly sensitive to environmental factors such as air quality. Pollution not only triggers flare-ups but can also worsen existing inflammatory symptoms.

Indoor pollutants such as dust and pet dander can also contribute to eczema flare-ups. The presence of these harmful substances can irritate the skin and prompt the body's immune system to react, resulting in the manifestation of disease symptoms.

To minimize your exposure to eczema, avoid areas with polluted air and wear protective clothing. In cases where disease flare-ups persist, medical treatment may be necessary. A dermatologist may recommend topical creams and ointments to reduce inflammation and soothe irritated skin, as well as oral medications in severe cases.

6. Rosacea: causing skin redness, flushing, and inflammation

Rosacea is also a chronic inflammatory skin condition characterized by redness, visible blood vessels, and small, pus-filled bumps on the face. Although the exact causes of disease are not yet fully understood, environmental factors such as air pollution can trigger its exacerbation.

Exposure to pollutants, along with UV radiation, can cause skin inflammation. It underscores the importance of protecting the skin from both contaminants and UV radiation during condition treatment.

7. Sensitivity: depriving the skin of its natural protective barrier

Air quality can also affect skin sensitivity, especially in people with pre-existing conditions. Exposure to pollutants and irritants can cause inflammation and damage the skin barrier, leading to increased skin sensitivity and the development of new types.

Then again, the composition of the air, such as nitrogen dioxide or particulate matter, can react with UV radiation to produce free radicals that can damage the skin, leading to the development of sensitivity.

Final remarks

Air quality can have a significant impact on the skin, resulting in various problems such as dryness, premature aging, acne, pigmentation, eczema, rosacea, and skin sensitivity. Such habits as smoking, environmental stressors, and UV exposure can exacerbate these issues.

As a countermeasure to the harmful effects of air quality, red light therapy can be a powerful tool since it is effective in treating and preventing several skin disorders, including acne, rosacea, and premature aging. According to the Heliotherapy Institute, this procedure can be more effective, cheaper, and safer than invasive methods.  You can check with a dermatologist to see if they offer powerful in-office red light therapy.

Fortunately, we can do something to protect our skin from harmful irritants in the air. Wearing protective clothing, using air filters, keeping your home at optimal humidity (40-60% relative humidity) and avoiding heavily polluted areas can help keep your skin healthy and vibrant.

Article by Benjamin Allemon

New methods to accelerate wound healing

New methods to accelerate wound healing

Although bandages and antibiotic ointment are staples in my house, doctors have need of more advanced treatments for wound healing beyond these simple first aid tools. By researching how our skin heals, they have incorporated pH adjustment, ions and lasers to help those who suffer from large or slow-to-heal wounds.  These are very non-invasive ways to help get patients back to their normal function more quickly and with less pain.

What’s your pH?

In our article on alkaline water, we discussed pH: what it is and that our bodies regulate the pH of our blood and tissues carefully.  Scientists took information on healthy tissue and compared it to wounds.  According to the 2021 book Digital Health: Exploring Use and Integration of Wearables (chapter 6), healthy skin has a pH value of approximately 5.5 (acidic), but for infected wounds, the pH value is in the range of 7-8.5 (neutral to alkaline).  The alkaline nature of pH in the wound is due to the presence of bacterial colonies and enzymes. When a wound is kept in an acidic condition, the fibroblasts proliferate more actively and the wound healing process is stimulated more while an infected wound shows a slightly alkaline pH environment due to certain enzyme activities, bacterial colonization, and formation of protein structures.  Consequently, several research groups have developed dressings which incorporate pH-sensitive materials.

In addition, this theory of how acidic environments prevent or retard infection holds true for other entry points of infection in the body:

Consequently, those tissues that are closer to neutral pH or alkaline, may be more susceptible to infection:

  • The normal pH for the esophagus is close to 7.0. (Johns Hopkins)
  • The eyes: “The normal physiological pH of ocular surface in humans to be 7.11±1.5. They also showed an increase in ocular surface pH early in the morning and a gradual increase in pH to more alkali levels during the day.” (2014 NIH article)
  • According to, “ A normal blood pH level is 7.35 to 7.45 on a scale of 0 to 14, where 0 is the most acidic and 14 is the most basic. This value can vary slightly in either direction.” 

Hence, it’s very important that microbes are stopped at our body’s first lines of defense!  Acidity is one way of preventing infection and speeding healing, but scientists have discovered that ions can also help.  As you may know, there are two varieties of ions: negative and positive.  They work in different ways to assist healing.  

Negative ions can be applied via negative ion misting machines (using sterilized water), corona devices, or bipolar ionization (like HypoAir units).  They produce negative ions by the hundred-thousand or millions, while normal air only has hundreds or thousands of the ions.  Negative ions were found to have antioxidant and anti-inflammatory effects in this 2021 study.  In this 2022 study, it was inferred that increased wound healing was due to a hydrogen peroxide scavenging effect provided by the ions.  

On the other hand, excess positive ions in the air do not promote healing, but positive ions produced by copper and silver are often used in bandages to do so.  These metals produce positive ions when they are placed in contact with the skin or wound, which enhance angiogenesis (formation of new blood vessels), anti-inflammatory power, as well as being anti-microbial to prevent infection during healing. (2014 study)  To increase contact and ions produced, researchers have designed bandages with nanoparticles of silver and/or copper.  

Lasers are another tool in the box for doctors to help their patients heal.  Traditionally low-power lasers and LEDs have been used in phototherapy of large or otherwise slow-healing wounds.  However, high-power unfocused lasers have also recently been used.  The advantage of lasers for wound healing are that they reduce pain, inflammation and exudates (weeping of fluids from the wounds), as well as reduce scar tissue and help the body to granulate tissue in a more organized way.  Laser sessions last only seconds to minutes and are painless for the patient, and in a matter of weeks they can see new skin being formed to close the wound.

Our bodies can normally heal themselves with simple wound care, but infections and  co-morbid conditions like diabetes or circulation problems can severely impact healing.  That’s when harnessing wound pH management, applying positive or negative ions, or laser therapy can help get the healing going.

What do spiderwebs and your home’s air filter have in common? (no spider pictures)

What do spiderwebs and your home’s air filter have in common? (no spider pictures)

Spiderwebs–and the creatures that make them–are not welcome in most homes.  Not only are spiderwebs a “sign” of poor housekeeping (although they often appear overnight), spiders themselves are feared or despised (admittedly I’m in this group).  Even many nature-lovers would rather relocate the spiders and tear down their webs rather than abide with them, but scientists have recently discovered that their webs contain a wonder material that filters air akin to the best air filters. 

It’s obvious that spiders are probably not interested in reducing PM2.5 with their webs: their primary goal is getting dinner.  Face it, though: we all know that spiderwebs do a great job of collecting dust!  Scientists found that the electrostatic properties of the glue that coats spider webs causes them to reach out to grab all charged particles, from pollen and pollutants to flying insects.  A quirk of physics causes webs to move towards all airborne objects, regardless of whether they are positively or negatively charged.  Webs can catch particles as small as aerosols and pesticides, making them perfect environmental monitors if we choose to examine them.  (How electricity helps spider webs snatch prey and pollutants)

It’s the statement that “all charged particles” are attracted to the web that caused us to investigate further.  How does that work?  Typically electrostatic filters work by charging all incoming particles either positively or negatively and then attracting them with an oppositely-charged filter.  Spiderwebs are not exactly the same, because the web has no control of the charge of the particles (insects or dust) flying toward it, yet it actively “springs” out toward them if they are charged (click here to see it happen–no spiders included!)

The fact is that as things fly through the air, whether it’s dust, water droplets, insects or airplanes, they collect a static charge. This is why airplanes have little “antennae” or rods sticking out of the back of the wings: these static dischargers disperse the charge back into the air.  Insects can easily acquire electrostatic charge by walking over charged surfaces or by flying in an airstream of charged particles. (Spiderweb deformation induced by electrostatically charged insects)  Just as humans accumulate static by walking through dry air and carpets during winter, low humidity likely amplifies the static charge of insects, too.  The deflection of the spider’s web depends on the mass of the particle or insect and their charge; small charged dust particles generate less deflection than larger insects.  So, although insects have sensors on the tips of their antennae for detecting electric fields, and the glue spirals can distort Earth's electric field within a few millimeters of the web,  sometime the total charge of the insect or their speed gets them in trouble, allowing the web to “reach out and grab” them!

But how does the spiderweb attract positive and negatively-charged objects?    According to the scientists, this is due to the ion mobility within the miniscule water droplets that the web’s adhesive surface attracts. A combination of the spiders’ naturally compound-rich silk and the droplets (which serve as both glue carriers and electrostatic conductors) imbues the web with these amazing electrostatic properties.  ('Electric' webs are spiders' secret to catching prey)

Orb weaver spiders are the common class of garden spiders.  Their webs are formed roughly in a circular pattern, hence the “orb”.  Their webs are also hygroscopic, meaning that they absorb moisture from the atmosphere, using salts to retain a specific amount of moisture.  

Since there are more positive ions in the air than negative ones during calm weather, most insects gain a slight positive charge as they fly through the air.  The web is usually “neutral” meaning it doesn’t have a charge, but as an insect nears it, moisture on the web allows electrons to migrate to the surface of the web near the insect and cause the silk to stretch out toward it.  

Static induction is the principle that guides this phenomenon, which you've experienced if you've ever rubbed a balloon on your head and stuck it to a wall. Rubbing the balloon causes it to gain a static charge, and then it induces the opposite charge in the wall. Materials that are poor conductors, like rubber or silk, produce the best static induction.

Similarly, static induction occurs between the spider web and an insect. As an insect carrying a positive charge nears the threads of the web, that positive charge attracts electrons in the spider silk, creating a temporary negative charge. That negative charge can then be attracted to the positively charged insect, causing the spider threads to snap out and stick to the insect. (Note to Flies: Avoid Fuzzy Socks)

The drops of water on the web also allow glycoproteins in the web to move around it and coat any insects that become entangled in a sticky glue.  Glycoproteins are proteins that have carbohydrates attached to them, which allows the glue to form a large number of hydrogen bonds.  In these types of bonds, hydrogen forms a positive dipole in one molecule and fluorine, oxygen, or nitrogen form a negative dipole in another molecule. The positive dipole of hydrogen is attracted to the negative dipole on the electronegative atom, creating an attraction between the two molecules. (  Although the hydrogen bonds are relatively weak, they are collectively strong enough to keep insects and pollen from escaping the web. (Glue Stays Sticky When Wet)

Spiders depend on the invisibility of their webs to catch insects, so when the webs become “dirty”, many spiders clean and repair them on a daily basis (Spiders and Their Webs).  To replicate the web and this cleaning action, other scientists took on the mission in 2020 of creating artificial webs that attract and release particles in a self-cleaning action (Ionic Spiderwebs)

Instead of repairing them, some spiders ingest the old web and its contaminants, including the water droplets on the web.  Web material is hygroscopic, meaning that after it exits the spiders body, it attracts water from the atmosphere.  (Water harvesting during orb web recycling)  This actually helps the spider by giving it a source of water from the air.  The pollen on the web is a bonus too:  pollen makes up to a quarter of the diet of orb weavers. Unfortunately, a lot of urban spiders end up ingesting microplastics, chemicals and tire components (from road dust).  

Spiders also build their webs with a minimum of material, to reduce waste and avoid having to clean or eat extraneous web.   Because the web material is stretchy, sticky and because of static inductance, webs can be constructed with holes to let wind pass through, at the same time catching much more pollen and insects than any plain non-stretchy, sticky material.  “Avoiding” capture is much harder for any insect or bit of pollen trying to fly “through” the web when its holes can close automatically by static attraction!   Simply put, spider webs are amazing particle capture machines, also known as filters.  It’s no wonder then that scientists are busy replicating them for different purposes.

Spider‐web‐inspired network generator (SWING) air filters, based on a unique electrospraying–netting technique, integrate properties of small pore size (200–300 nm) and innovative self‐charging capacity (3.7 kV surface potential), enabling the synergistic effect of physical sieving and electrostatic adhesion for PM removal.  High efficiency (>99.995%), low pressure drop (<88.5 Pa), high transparency (>82%), robust bioprotective activity, energy‐saving, and long‐term stability for MPPS PM0.3/pathogen removal were achieved.  The filters are made of electrospun nanofibers (PVDF material) and carbon nanotubes, which are uniquely formed by using a droplet spray–deformation–assembly process during electrospinning (Spider‐Web‐Inspired PM0.3 Filters Based on Self‐Sustained Electrostatic Nanostructured Networks)

The silk proteins in spider webs themselves were determined in the early 2000’s (Spider Silk Proteins – Mechanical Property and Gene Sequence).  Spider silk is desirable not only for strength (it is superior to nylon, kevlar, silkworm silk and steel in elongation at break, tensile strength and breaking energy), but it’s also bio-compatible to humans and so can be used in medical applications.  Artificial spider silk has not been easy to develop.  Although the primary proteins were discovered earlier, It took a lot of gene-sequencing work to discover a formula for getting the optimal amount of nanocrystals in the silk.  Once the protein sequence was determined, scientists needed to figure out who or what should be used to make the silk?  Spiders themselves are too aggressive and territorial to be farmed. (Artificial Superstrong Silkworm Silk Is 70% Stronger Than Spider Silk)  For this reason, bacteria, silkworms and goats have been bio-engineered with spider DNA to produce the silk. (Artificial Spider Silk Is Stronger Than the Real Thing, Spider Silk, BioSteel Goat)

Filter production methods: Traditional Needle Electrospinning (ES) requires extensive preparation, time, and post-treatment to produce filter material, as shown in this video.  In this article, Centrifugal Electrospinning (CES) was found to be the most effective method in mimicking the fiber and composition of spider webs, albeit in a random non-woven way.  The suitable spinning conditions for the recombinant spider silk protein eADF4(C16), including protein concentration, process flowrate, electric field strength,and rotational speed were analyzed.  Experimentation with these variables enabled researchers to develop a roll-to-roll production process that is up to 1000 times faster than traditional electrospinning processes that also required no post-treatment.  

So–knowing that spiderwebs are such efficient filters and their silk is now the object of much scientific research and investment, has this information changed your opinion of spiderwebs in your home?  It’s ok, I know that fear of spiders is hard to dispel.  So with you, I say, bring on the artificial spider silk, please! 

Are There Water Filters Growing in Your Backyard?

Are There Water Filters Growing in Your Backyard?

According to a March 2023 United Nations World Water Development Report, around 2 billion people do not have access to clean and safe drinking water.  (Billions of people lack access to clean drinking water, U.N. report finds)  Many organizations develop new water filters every year, but the major problems with these filters are the cost and availability: even relatively low-cost filters are prohibitively expensive for many.  Also, people would rather pay small daily increments for fresh water rather than a single large payment for a filter.  This is one reason that many people in India pay daily to have access to fresh bottled water, rather than purchase a filter that costs more. 

Researchers at MIT found that local trees have natural filters that can actually purify water to drinking water standards. (MIT engineers make filters from tree branches to purify drinking water)  Xylem is the vascular tissue that conveys water and dissolved minerals from the roots to the rest of the plant and also provides physical support. Xylem tissue consists of a variety of specialized, water-conducting cells known as tracheary elements. (  The interiors of non-flowering trees like pine and ginkgo have sapwood that contains xylem which even filters out bacteria.  The sapwood of such trees also have shorter conduits in the xylem than flowering trees, so that water must pass through a number of “pores” in the xylem, which are the main filter elements that remove microbes.  In trees, the pores are not used to filter water, but rather separate gas bubbles that would block the xylem.  Here is a diagram of how water is filtered through xylem; the pores being the disc-shaped aperatures:

Courtesy: N.R. Fuller, Sayo Studio

Although the images above are microscopic, the entire filter is a 1-cm long piece cut from the cross-section of a branch:  

Source: Xylem Water Filter manufacturing process video

Next, the wood filter is inserted into a tube and secured with a hose clamp.  Voila, you have the main part of your wood water filter!

Source: Make your own Xylem Water Filter! video

Two additional preparation steps of soaking the wood filters in ethanol and drying them out completely in an oven caused them to be less prone to clogging, as well as extending their shelf life.  

The researchers took the concept to a suburb in the Indian city of Delhi, where 30 million people live.  Many people there are susceptible to intestinal illnesses and death due to poor quality drinking water.  The MIT team went into neighborhoods with water access issues and demonstrated that the filters were simple and cheap to replace.  Many people who saw them demonstrated confirmed that they could either make or purchase the wood filters sustainably, for easier access to clean water.  

Want to make a xylem filter yourself?  This free website gives all the information needed to select a tree and construct the filter, which is a great science experiment for kids.  

The filters are still under development, because it’s not known whether they can remove chemicals, metals or other contaminants.  However, unlike many novel water filters coming from universities or private firms, this one is quite inexpensive, simple and has easily-sourced parts.  It seems that even survivalists should be glad to know this information–and you might want to keep it handy for your next camping trip!

Photo by Airam Dato-on on Unsplash

To-Do List: Change the Cabin Air Filter in your car and ADD CARBON!

To-Do List: Change the Cabin Air Filter in your car and ADD CARBON!

I know, car maintenance is not everyone’s “thing” and air filters sound super-boring.  However, if you’ve owned your car for a while and never changed the filter, or bought a used car and have no clue when this filter was last changed, you could be horrified at what you would find (and hence are breathing in every time you drive it)!  It’s time to think of this task as a “health upgrade” for you, the driver or passenger!

Cabin air filters in cars (tip: these are different from the engine air filter) are probably even more neglected than household air conditioning or furnace filters, for several reasons:  our car ventilation systems are exposed to even more dust, toxins and critter debris than our homes, and many people are averse or afraid of car maintenance.   However, it’s so easy to order the right filter online with your car’s model and year, and now virtually every maintenance procedure on every model car can now be found on YouTube.  There’s no excuse for rolling up your sleeves and getting to it (or bribing your teenager or neighbor to do it with some food)!   Simple tools like screwdrivers, sockets and a vacuum cleaner are usually the only things needed. 

Before you order the filter, however, check to see if they are available with activated carbon.  If so, definitely get that one.  Not only does carbon help with smells in your vent system and car interior, it can remove NO2 from ventilation air.  Nitrogen Dioxide (NO2) is a by-product of fuel combustion and it irritates our respiratory system, causing flare-ups of asthma, which can trigger a visit to the emergency room if the coughing and difficulty of breathing is not controlled.  Over time, NO2 can actually cause asthma or respiratory infections.  A study in the UK at the University of Birmingham showed how much the activated carbon lowered NO2 levels compared to basic pollen filters.  In heavy traffic, many people close the windows and put the ventilation system on “recirculation mode”, which helps reduce NO2 levels by about 1.6 times compared to open windows.  However, you shouldn’t keep the windows closed and recirc on for extended periods of time because CO2 levels will start to rise; maintaining appropriate ventilation is also important to prevent drowsiness.  Here’s the alternative:  using external ventilation with activated carbon filters fitted.  Even with fresh air coming through the ventilation system, NO2 levels were 6.6 times lower than levels with windows open.  Also, in-vehicle NO2 levels were on average 14.3 times lower with closed windows and recirculated air.  It just makes sense to go with activated carbon if it’s available in a filter for your car. 

With minimal research and $, you can feel a lot better about the air you breathe on every drive.  Then, you can place a reminder on your calendar to do it again next year, and keep up the good habits!

Photo by Ivan Bogdanov on Unsplash

Phytoremediation Cleans Up Soil Naturally

Phytoremediation Cleans Up Soil Naturally

It’s happened to the most careful and graceful of us: a cup of coffee or plate of spaghetti sauce lands on the carpet, upside-down, of course. Out come the carpet cleaners, vacuum cleaner, or if you’re really prepared, the carpet-cleaning machine, and we do our best to treat the area and cordon it off for “drying”.  If the offending stain doesn’t appear again, case closed.

But what if you or someone else spills a toxic chemical on a large area of your lawn?  How do you remove that? There are no “lawn cleaners”...or maybe there are. 

The Environmental Protection Agency (EPA) is the U.S. agency concerned with not only monitoring, but cleaning up those big spills or more unfortunately “dumps” in the U.S.  It mandates how the sites are cleaned up and should hold individuals or corporations liable for the damage.  Unfortunately, as long as there is industry, there will be accidental, and often intentional, spill on land and water.  However, sometimes, the “cleanup” may not look like cleanup at all, if phytoremediation is used.  A toxic waste cleanup site may look like any other green field.

Phytoremediation refers to the different ways plants can be used to “clean up” contaminated soil.  Around  400  species  of  plants are called “hyperaccumulators” because they absorb unusually large amounts of metals in comparison to other plants.   These  plants  have  been found to accumulate metals at a rate 50 - 100 times higher than normal plants.  (Phytoremediation of soil metals)  They do this in a number of ways; the following terms are taken from the EPA’s Phytoremediation Resource Guide:

  • Phytoextraction: some plants take up metal contaminants in the soil by plant roots and move them into the aboveground portions (stems, leaves, fruit). 

  • Rhizofiltration: some plants adsorb contaminants from ground water onto their roots, or in the case of aquatic species, the plants live in contaminated water (like wastewater). Duckweed is a species that has been shown to remove many types of heavy metals from water. (Duckweed: A Model for Phytoremediation Technology)

  • Phytostabilization: some plants are used to immobilize contaminants in the soil and ground water through absorption and accumulation by roots, adsorption onto roots, or precipitation within the root zone. This process reduces the mobility of the contaminant and prevents migration to the ground water or air, and it reduces bioavailability for entry into the food chain.

  • Phytodegradation: some plants take up contaminants and break them down through metabolic processes within the plant, or through the effect of compounds (such as enzymes) produced by the plants. Pollutants are degraded, incorporated into the plant tissues, and used as nutrients.

  • Rhizodegradation:  the breakdown of contaminants in the soil through microbial activity that is enhanced by the presence of the rhizosphere and is a much slower process than phytodegradation. Microorganisms (yeast, fungi, or bacteria) consume and digest organic substances for nutrition and energy.  This is becoming a very popular topic and technology as scientists learn how to modify and genetically engineer microbes for particular purposes.   

  • Phytovolatilization:  some plants are able to take up and transpire (breathe out) contaminants, releasing the contaminant or a modified form of the contaminant to the atmosphere.  It is known that trees with deep roots transpire radon from the ground and groundwater.  

So, once the area is planted with hyperaccumulating plants, what happens next?  Unless the contaminant is phytodegraded, meaning, the plant breaks it down, the plants will still contain the contaminants, so they must be harvested and disposed of properly.  If testing reveals that they indeed have higher-than-acceptable levels of the contaminants (actually, this is a good outcome), they are either composted or dried and incinerated, and the waste remaining is securely buried.  Then the process is repeated until the soil is cleaned to an acceptable level.  The difference between phytoremediation and traditional soil removal is huge:  typically the amount of material to be incinerated from phytoremediation is only 10% of that required by traditional soil removal.   Here is a video of an EPA phytoremediation project in Crozet, VA where arsenic is removed from the site of an old apple orchard by planting and harvesting ferns that were bioengineered for the purpose of extracting arsenic.

What does this mean for the average homeowner?  Unfortunately, many private lands are poisoned with any number of contaminants: lead paint from old buildings, pesticides from farms and aerial contaminants that settle from spraying for insects or crops are all sources of contaminants.   You might not even be aware of old fuel tanks or lines that were buried decades ago, before you purchased the land, and have begun to leak, or maybe a new industry is releasing chemicals upstream of your land.  With any knowledge or suspicion of contamination, consider if you or your family will be exposed to the soil, and decide whether to get the soil tested.  If children or animals are regularly in contact with the soil, or you want to grow edible plants and vegetables on the land, testing is a good idea, so you know what chemicals you’re dealing with and which plants may be able to help you!  Here is a great article on how to gather soil samples and available testing centers. 

If you do find contamination on your land, here are some actual plants that could help clean up the soil: 

  • Grasses: Indian Grass has the ability to detoxify common agrochemical residues such as pesticides and herbicides. Indian Grass is one of nine members of grasses that assist in phytoremediation plants. When planted on farmland, the reduction of pesticides and herbicides is significant. This list also includes Buffalo grass and Western wheatgrass, both capable of absorbing hydrocarbons from the land. (Phytoremediation Plants Used to Clean Contaminated Soil)

  • Sunflower plants were demonstrated to have removed 95 percent of uranium from a contaminated area in a 24-hour period. This highly successful crop is a powerful tool for the environment because of its ability to remove radioactive metals from superficial groundwater, so they were used in cleanup after the Chernobyl nuclear disaster, which left nearby soil and water heavy with the radioactive elements cesium and strontium. The process works because the isotopes “mimic” nutrients that the sunflower would naturally absorb – cesium mimics potassium, which plants need for photosynthesis, and strontium passes for calcium, which provides structural support. Unfortunately, sunflowers did not work so well for Fukushima, Japan, because the isotopes released were very different from Chernobyl. (Why Scientists Plant Sunflowers After Nuclear Disasters).  Sunflowers are also good at absorbing metals such as lead, arsenic, zinc, chromium, copper and manganese. Indian mustard removes lead, selenium, zinc, mercury and copper.  Hydrangeas draw out aluminum from the soil.  (Superplants clean up toxins from contaminated soil)

  • Trees can do their part:  Willows and poplars have been shown to be strong phytoremediators, not to mention being beautiful.  Carbon tetrachloride, a well-known carcinogen, is easily absorbed by poplar tree roots. They can also degrade petroleum hydrocarbons like benzene or paint thinners that have accidentally spilled onto the soil. (Phytoremediation Plants Used to Clean Contaminated Soil)

  • Vegetables:  Of course, if you know that there’s soil contamination and you grow vegetables to remove it, you must take care not to let anyone or any animals eat the vegetables or plants.  Certain vegetables only take contaminants into their root systems, but others draw them up into the leafy greens of the plants.  Cruciferous vegetables like broccoli, kale, collards, mustards and also corn are considered hyperaccumulators.  (Superplants clean up toxins from contaminated soil)

  • Mushrooms: Like phytoremediation, mycoremediation is the use of fungus or microbes to clean the soil.  It’s hard to believe that edible mushrooms are in the same class as toxic mold, but they are both fungus, and can be used to absorb and/or break down pollutants.  As mycelium spreads, it secretes enzymes which can break down pollution.  For example, oyster mushrooms have been used to remove E. Coli from Chicago River water, harmful Polycyclic aromatic hydrocarbons (PAHs) and TNT from water sources contaminated by wildfire ash, and diesel-contaminated fields from 10,000 parts per million (ppm) of PAHs to less than 200 ppm in eight weeks.  Turkey Tail, Shiitake and White-Rot Fungus are three other useful mycoremediators. (Mycoremediation: 8 Ways Mushrooms Can Mitigate Pollution)

The downside of hyperaccumulating plants is when they are grown and consumed without testing/regulation of the contaminants in them.  Unfortunately, brown and white rice (they are the same grain; brown rice is simply the whole grain while white rice has been milled and polished) are hyperaccumulators of cadmium and arsenic.  Arsenic is a more common pollutant; in the US, it gets into rice through pesticides used in old cotton fields that are flooded to farm rice, and through contaminated groundwater that floods fields in Bangladesh, for example.  The rice plant often takes up arsenic in place of silicon; rice plants require large amounts of silicon for optimal growth, and the chemical form of arsenite (AsIII) is very similar to silicon.  (Arsenic Transport in Rice and Biological Solutions to Reduce Arsenic Risk from Rice)  This is a very serious problem in eastern cultures where rice is a main staple of the diet for millions of people, and even those who can’t eat gluten, a protein in wheat that causes severe allergies in some people.

Unless you are reclaiming a swamp, new pristine land is not being created in great quantities, so we’re left with land that has centuries or millennia of human footprints, including toxic chemicals and metals.  Human use of the land in general leaves it in worse condition, but with the right plants, it’s possible to reverse a lot of the contamination.  If you want to make your own land–whether it’s your suburban backyard or acres in the country–cleaner and more habitable, get the soil tested and research which hyperaccumulating plants will make it better.  Once you get past the latin plant classifications, you may find the right plants also bring aesthetic beauty you wouldn’t have imagined. 

Photo by Markus Spiske on Unsplash

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