All Posts by Jennifer Faul

What does living near a farm mean?  It’s not all cute baby animals.

I didn’t grow up near a farm, but I spent a lot of time on one.  My mother’s uncle was a farmer who raised soybeans, corn, a few pigs and an extensive home garden.  Although my sister and I had to shell a lot of peas and shuck a lot of corn, we also got to play on the hay bales and jump in the soybean pile when the adults weren’t looking.  Farms through the eyes of a child are wonderful until we really learn what makes the garden grow (and not be eaten up by pests). 

I feel for farmers.  They are at the mercy of the weather (which has been crazy during the past few years) and pests, as well as an economy that expects perfect specimens of fruits, vegetables and meats delivered to their front door (literally) for the cheapest price possible.  Although I’m indebted to farms for providing the food I buy at the supermarket, I wouldn’t want to live near one.  At least not the kind that produces non-organic food for the supermarket, because it takes a lot of pesticides, herbicides and fertilizers in order to get that kind of production to a profitable level.   

Application of pesticides is often done by airplane, and low level pesticide vapors that are present in the air linger for days and sometimes weeks after application on food crops. Some pesticides react with sunlight (in a process known as photolysis) to form new chemicals that are more toxic than the original.  (Living Near Agriculture Increases Health Problems)

Many studies show that adverse effects from pesticides can be seen in people living up to one mile away from where they are sprayed.  In rural areas where farms abound, it can be difficult to stay out of this zone, and for the farmer’s family, it’s a fact of life  Some of the diseases which have higher rates surrounding farms include:

• Diabetes: 21 studies presented at the 2015 European Association for the Study of Diabetes show pesticides increase the risk of diabetes by 61%. 
• Birth defects: According to this 2001 study, ifpesticide exposure of pre-born babies occurred between the 3rd and 8th week of pregnancy, there was a 40% increase in major birth defects ending in fetal death.
• Brain cancer: Researchers from the Boston University School of Public Health compared the home locations of approximately 1000 cancer patients to the home locations of 1000 patients dying of illnesses not related to cancer. Results showed that living within 2600 feet of the cranberry growing area resulted in twice the risk for all brain cancers and nearly a 7-fold increased risk for a type of brain cancer known as astrocytoma.
• Autism: the study, “Maternal Residence Near Agricultural Pesticide Applications and Autism Spectrum Disorders among Children in the California Central Valley”  showd that the risk of having a child with Autism Spectrum Disorder (ASD) was 7.6 times higher than normal if their homes were located within 500 meters (< 1/3 mile) from pesticide treated fields, crops were treated using the pesticides dicofol and endosulfan, and the pesticides were applied between week 1 and week 8 after conception.  The risk of ASD increased with the pounds of pesticide used and decreased with distance from the treated fields.
• And many more, including infertility, miscarriage, Parkinson's Disease, immune system damage, leukemia, developmental brain damage in children, higher rates of child cancers, non-Hodgkin's lymphoma, autoimmune disorders, arthritis and lupus.

Many of these diseases can be prevented by our body’s own first line of defense, a liver enzyme known as cytochrome P-450. It breaks down pesticides in the blood into a less toxic form. Some people, however, have only 1/3rd the normal levels of these important enzymes, and therefore, would have higher levels of pesticides in their blood for longer periods of time, thereby resulting in more harm from the chemical.  In addition, Glyphosate residues are found in the main foods of the Western diet, comprised primarily of sugar, corn, soy and wheat. Glyphosate, the active ingredient in Roundup®, is the most popular herbicide used worldwide. Glyphosate's inhibition of cytochrome P450 (CYP) enzymes is an overlooked component of its toxicity to mammals. (Glyphosate’s Suppression of Cytochrome P450 Enzymes and Amino Acid Biosynthesis by the Gut Microbiome: Pathways to Modern Diseases)  

What about livestock farms?  Like other industries, farms tend to survive by merging, and the largest livestock farms are termed “CAFOs” for Concentrated Animal Feeding Operations.  CAFOs are agricultural meat, dairy, or egg facilities where animals are kept and raised in confinement. Instead of grazing or eating in pastures, fields, or on range lands, animals are given food.  The animals, feed, waste, and production operations are all confined to a small area of land.  (Environmental Health: Concentrated Animal Feeding Operations (CAFOs))  CAFOs are not all bad: Potential benefits of CAFOs include an economy of scale that affords more efficient sewage and manure management and, in some cases, improved control of some pathogens. For example, trichinosis from pork has been significantly reduced by the improved rodent control made possible by confined feeding operations. (Exploring Health and Environmental Costs of Food: Workshop Summary.)

According to a 2017 commentary, livestock farms–particularly poultry and swine barns–emit large amounts of dust particles from manure, bedding material, straw, animal feed, feathers, skin flakes, and hair.  The dust may be contaminated with bacteria and viruses that are mostly harmless for humans, although pathogenic organisms such as avian influenza virus (bird flu) or coxiella burnetii, the bacterium causing Q-fever, can under certain circumstances be found in the air near farms.  Farm operations also emit a mixture of gasses such as ammonia, an irritant gas that is formed by enzymes in animal waste.  Ammonia is primarily emitted by cattle farms, and by the application of manure to agricultural land.  Ammonia reacts with combustion-derived gases in the atmosphere (primarily from industrial and traffic emissions) to form secondary inorganic aerosols, which contribute to fine dust air pollution. (Is Living Near a Farm Bad for Your Health?)  

A 2021 study found that US agriculture results in 17,900 deaths (range across models: 15,600 to 20,300) per year via reduced air quality, 

• Damages are driven by NH3 (ammonia) emissions (12,400 deaths; 69% of total) mainly from livestock waste and fertilizer application.  At many beef, pork and dairy facilities, animal waste is stored in massive “lagoons,” such as the one near Herring’s mother’s home in Duplin County. There, the microbes that break down feces release huge amounts of ammonia. Many facilities spray nitrogen-rich liquid waste on nearby farm fields, another source of contamination. (Air pollution from farms leads to 17,900 U.S. deaths per year, study finds)
• Primary PM2.5 is also a major contributor (4,800 deaths, 27% of total), largely from dust from tillage, livestock dust, field burning, and fuel combustion in agricultural equipment use. 
• NOx, SO2, and NMVOCs are minor contributors (collective total: 700 deaths; 4% of total). 
• Areas causing the greatest damages are spatially concentrated, with the top 10% of the most damaging counties (308 counties) together responsible for 8,400 deaths per year (47% of total deaths). These counties are mainly located in California, Pennsylvania, North Carolina, and along the Upper Midwest Corn Belt.

According to a study performed in the Netherlands with 2500 neighboring residents of livestock farms, ambient ammonia concentrations were associated with worse lung function, and people living closer to poultry and goat farms were at increased risk of pneumonia. The location of the study in the southeast Netherlands is very informative, as it is densely populated and also a region of intensive swine, poultry, cattle and goat farming.  As a result of the research, the Dutch government planned to reduce poultry barn emissions by 50% over the following ten years.  

On the bright side, the same Dutch study found that people who lived within about 1,000 feet of livestock were 27 percent less likely to have allergies than those who lived farther away.  Specifically, people living within about 1,600 feet of a pig farm were 37 percent less likely to have allergies than those who lived more than roughly 1,900 feet away. And living no more than 1,300 feet from a cattle farm was linked with a 32 percent lower risk for allergies, the study found.

According to Dr. Alan Mensch, a pulmonologist at Plainview and Syosset Hospitals on Long Island, N.Y., "elevated levels of components of [potentially protective] gram-negative bacteria were prominent in the atmosphere around farms and downwind in areas in close proximity to farms.” These "helpful" bacteria may bolster the human microbiome -- the collection of trillions of helpful germs living in our bodies. And "the less we are exposed to various microbiomes prevalent on livestock farms, the more likely are we to develop allergic diseases," he theorized. (Even Living Near a Farm Might Help Prevent Allergies)

Water quality is also a concern when living near a farm.  Farms can contaminate groundwater by agricultural runoff from poorly managed animal feeding operations, overgrazing, overworking the land (for example, plowing too often), or poorly managed and ineffective application of pesticides, irrigation water, and fertilizer. (Water Contamination)  Therefore, you should get a water test done of any well water on a property near a farm before purchasing, because chemicals could make the water undrinkable, and microbes such as E.Coli could require purification equipment.  

Farms are necessary, for sure, but their use of large amounts of chemicals and densely-packed animals can make them poor neighbors.  Since we can get dangerous pesticides into our bodies without even living near farms (this article tells how one such chemical is ingested and its use being deregulated), are the additional risks that come with living near a farm worth the “peaceful” atmosphere?  It’s a complex question that is likely split between those who have not had serious health issues, and those who have (similar to those sensitive to mold).  Once again, research and divine guidance are the best ways to answer the question for yourself!

What are Probiotics for the Air?

Probiotics have been around for a long time, even millenia!  Probiotics are live, active microorganisms ingested to alter the gastrointestinal flora for health benefits. They often are referred to as good bacteria in the gut and compete with bad bacteria to support the body in establishing optimal digestion and aid immune function. (An Introduction to Probiotics)  Now, they didn’t always exist in “capsule” form.  In fact, if you look in  the refrigerated section of the grocery store, probiotics are the cultures found in kefir, kimchi (fermented cabbage), kombucha (a fermented tea), miso (a fermented soybean paste), pickles, sauerkraut, tempeh (another fermented soybean food) and yogurt.  The common thread of all these foods includes fermentation, which is the breaking down of organic substances through the action of enzymes.  Bacteria are the carriers of these enzymes, so as the fermentation occurs, these good bacteria increase.  When we ingest fermented foods, the bacteria populate our intestines for better digestion. (Check out our article on fermentation!)

Now that you know probiotics have been in foods since antiquity, probiotics for the air and surfaces in your home is a relatively new concept.  BetterAir was the first company to use probiotics in an air purifier.  According to BetterAir President Tom Staub, “Allergens, pathogens, germs etc. do not grow in the air, but are born and propagate on surfaces and objects.  Since they are microscopic they are then propelled into the air by minute movements of air such as the wave of a hand across a tabletop or fall off a foot upon stepping onto carpet.”  BetterAir’s proprietary probiotic formula consumes organic allergens often found inside the built environment like pollen, mold spores, pet dander, and dust mite fecal matter. Staub continues, “They also consume the food sources that germs and pathogens need in order to multiply and propagate thereby minimizing their presence. Fewer pathogens on surfaces and objects results in cleaner air, surfaces and objects. “ (BetterAir: The First Air Purification Device To Utilize Probiotics To Clean Your Home’s Air)

Considering that probiotics contain live bacteria, an air purifier that sprays them into the air may be, well, a little scary to some!  Rest assured, however; BetterAir’s proprietary formula’s active ingredient consists of naturally occurring (non-GMO), safe and effective Bacillus strains.  

Bacillus encompasses a large number of bacteria types, and some are harmful, but many are helpful, such as the medically useful antibiotics  produced by B. subtilis (bacitracin). (bacillus bacteria)  In order to produce and market Enviro-Biotics, BetterAir passed all the required tests by EPA standards at EPA-certified GLP (Good Laboratory Practice) labs, became EPA registered (94339-1, August 2021), and the US Food and Drug Administration (FDA) declared Enviro-Biotics as GRAS – Generally Recognized as Safe.  Finally, it has been certified by many government and private healthwatch organizations.  So, the liquid dispersed by BetterAir systems is safe for people, pets and plants.  

The following video screenshot shows how a petri dish treated with drops of Enviro-Biotics (right) forms a barrier that stops black mold from growing, unlike the untreated dish on the left.  This is visual proof of what their technology claims: microscopic sized Environmental Probiotics form a protective layer of microflora on all surfaces and objects, where the probiotics agents deny pathogens (mold and bacteria) access to nutrients (food), therefore obstructing and disabling growth of pathogens on these surfaces and objects.  In addition, and concurrently, Enviro-Biotics consumes harmful organic particles that are the source of allergies and diseases. Since dust and dander will be in every household to some extent, by introducing good bacteria, these allergens are used to feed the good and starve the bad bacteria.

Source: The Power of Enviro-Biotics

If your home is in an exceptionally dusty or polluted area, BetterAir has also combined a probiotic air purifier and a HEPA air purifier. 

Another way to use probiotics is to clean with them.   HomeBiotic has spray bottles for spritzing the air and surfaces that are smelly, which starves bad bacteria and protects from its regrowth for up to 5 days.  Their cleaning bundle has tablets that dissolve in water to make a non-toxic, powerful cleaning solution that is safe to the homebiotic bacteria they promote, and nano-sponges that clean without spreading germs around your home.  The tablets are made of washing sodas and citric acid, which are completely safe for people and pets. Citric acid in the right dose, for example, is an EPA-approved, non-toxic sanitizer that kills norovirus.  However, citric acid should not be used on natural stone or marble, wood, delicate surfaces or electronic screens because it may damage them.

Although probiotics are not a “silver bullet” for all airborne contaminants, they may help allergy sufferers and may help you to maintain health better when seasons change and new contaminants come into the home.  It’s like your gut: taking probiotic supplements feeds the good bacteria and doesn’t leave a lot of room for the bad to multiply out of control.  Therefore good effects of probiotics in the home depend on consistent use over a period of time, and avoiding chemicals like bleach that kill both good and bad bacteria indiscriminately. With new technology advancing everyday, it probably won’t be long before we can “see” exactly what is colonizing our homes and bodies, and then get tailored solutions to optimize it.  Since probiotics already live outside in the natural world (in soil, wood and other natural surfaces), like ions are present in fresh outdoor air, bringing probiotics indoors could be a good idea for keeping our homes healthy with natural methods and substances!

Are your air purifiers and emergency supplies ready?  Bad air quality can come from any direction!

“Wildfire season” historically starts June 1, but the concept of a “fire year” is more accurate when fires in Canada begin in April.  This year’s fires in British Columbia and Alberta started in April, and now nearly all of Canada’s ten provinces have fires burning.  The problem for Americans, especially northern states, is that air currents carry the smoke aloft and bring it to remote places, sometimes thousands of miles away.  Certainly people on the mid-Atlantic coast did not expect to see hazy skies or low air quality, but we now know that distant events can wreak havoc on our air quality.  

Take for instance volcanoes.  According to research published in 2018 by scientists at the Imperial College of London, Napoleon’s defeat at Waterloo in 1816 may have in part been caused by a volcanic eruption in Indonesia two months prior.  This eruption of Mount Tambora was the most destructive explosion on earth in the past 10,000 years, killing over 90.000 people and blasting 12 cubic miles of gasses, dust and rock into the atmosphere and over the island and surrounding area.  (Blast from the Past) The ash spewed into the air was carried even higher than it would be by winds alone, due to electrostatic forces.  Negative charges from volcano plume gave the ash a negative charge, repelling it into the air and even as high as the ionosphere, which is a layer of our atmosphere that extends from 50-400 miles above the earth and is responsible for cloud formation.  Even though the charged ash did not reach Europe, it “short-circuited” the ionosphere, initially stopping clouds from forming.  Later, however, the clouds surged back, inundating places like Waterloo which normally only had 2” of rain for the entire month of June.  On 16-18 of June 1815, however, the area received unseasonably heavy rains that made the earth very soft, slowing down cavalry and artillery movements, and delaying the battle on June 18 so that the Prussian forces arrived in time to support the Allies and defeat Napoleon.   This type of cloud suppression was documented following the eruption of another Indonesian volcano, Krakatau in 1883, and reports of ionosphere disturbance followed the eruption of Mount Pinatubo, Philippines in 1993.  

So now we know that volcanoes can interrupt flight schedules, battle plans, and…global rain clouds.  Less rain equals more drought, and more drought equals more wildfires.  When the clouds come back to a drought-damaged area, lightning can spark many fires. In Quebec, for example, fires were sparked by lightning, but officials in Alberta have said that the cause of fires there is currently unknown.  (How did the Canadian wildfires start?)   This is how volcano eruptions can change world events and weather, halfway around the world!  

So, while interruptions to daily activities in the Northeast are hopefully temporary due to the Canadian wildfires, we have to look further to be prepared for the next blanket of wildfire smoke.  Studies regarding erupting volcanoes have shown that they have different atmospheric consequences depending on which hemisphere they are located.  Here are some of the results:

• Scientists studied 54 large explosive eruptions during 501–2000 AD including 16 in the Northern Hemisphere (NH), 25 equatorial and 13 in the Southern Hemisphere (SH).  In the first two years following an eruption, NH volcanoes decrease NH monsoon volume, and SH volcanoes decrease SH monsoon volume.  They tend to have the opposite effect on the opposite hemisphere, for example, a volcano in the NH will increase precipitation in the SH the first year, with diminished increase in the second year.  (Global monsoon precipitation responses to large volcanic eruptions)

• Long-term, however, volcanoes near the equator tend to have greater impacts than the high-latitude eruptions on global climate because their stratospheric aerosol clouds cover a larger surface area and have a longer residence time, and because the aerosols are then transported poleward in both hemispheres and eventually cover the entire globe. (Climate response to large, high-latitude and low-latitude volcanic eruptions in the Community Climate System Model) 

• Volcanoes inject a number of things into the atmosphere when they erupt.  Rocks and larger particles are the first to fall out of the atmosphere, ash can linger for several months, H20 , N2, and CO2 are the most abundant, and sulfur aerosols are responsible for reflecting light back into space and generally cooling the atmosphere. For example, the Pinatubo eruption in 1991 injected an estimated 20 metric tons of SO2 into the atmosphere, leading to a temporary (∼2 years) reversal of the late twentieth century global warming trend.  Did you know that volcanoes also inspire art?  The famous 1893 Edvard Munch painting, "The Scream," shows a red volcanic sunset over the Oslo harbor produced by the 1892 Awu eruption, and the 1815 Mount Tambora explosion inspired the novel Frankenstein by Mary Shelley due to the 1816 “year without a summer” which was unseasonably cold and gloomy. (Volcanic Eruptions and Climate)

• Mount Tonga, an equatorial submarine volcano, released an enormous amount of water vapor high into the atmosphere (mesosphere) when it erupted in February 2022, which caused weather anomalies globally.  Increased rainfall in the southern hemisphere following the jet stream was recorded, and much of the northern hemisphere had drier conditions than average.  (Influence of Volcanic Activity on Weather and Climate Changes)

But non-volcanic activity can be just as dangerous... 

• Halocarbons, used in foam insulation, refrigeration and other appliances, were released during the 2011 Tohoku earthquake in Japan, amounting to 6600 metric tons.  This is an increase of 21-91% over typical levels of six halocarbons that deplete ozone, which in turn affects weather patterns.  (Deadly Japan Quake and Tsunami Spurred Global Warming, Ozone Loss)  Of course, the major headline after this earthquake was the destruction of the Fukushima-Daiichi nuclear plant when the earthquake disabled the power and cooling to its three reactors.  There were no deaths or cases of radiation sickness from the nuclear accident, but over 100,000 people were evacuated from their homes as a preventative measure.  (Fukushima Daiichi Accident)

• Other natural disasters have damaged nuclear plants, like a 1998 tornado that knocked out power to the Davis-Besse plant outside Toledo, Ohio, and Hurricane Andrew, which knocked out power to the Turkey Point plant south of Miami site for five days in 1992. In 2008, Hurricane Gustav damaged the River Bend Nuclear Generation Station in St. Francisville, La.  At both Davis-Besse and Turkey Point, the plants' emergency diesel generators kept the equipment running until crews fixed the power lines. (Can U.S. Nuclear Plants Handle a Major Natural Disaster?)

• The Carrington Event of 1859 was the most intense geomagnetic storm in recorded history.  Earth narrowly missed receiving another series of solar flares in July 2012, which may have exceeded the strength of the Carrington event and prompted widespread power and communications outages. (Carrington-class CME Narrowly Misses Earth) 

It just goes to show that natural disasters can have global consequences.  For the next weather changes and wildfire risks, we could look far and long, or just be prepared with extra filters, masks, food and water, and a well-sealed home.  This is prudent because unfortunately, it only takes one badly-placed volcanic eruption, solar flare, earthquake, hurricane or tornado to upset a nuclear power plant or spew toxins into the air, sending the world and its weather into chaos.  

How can I get more filtration with my current HVAC system?  It’s a tug of war!

At a staff meeting one day, one of our team members related how the HVAC company which installed the central AC system in his new home recommended using the lowest MERV filters available.  I was shocked!  Well, after thinking about it some more, I hypothesized they were waiting for his evaporator coil (the part that transfers absorbs heat from the air by transferring it to the cold refrigerant) to plug up so they could sell him a new system.  In this day and age of availability of every type, face size and thickness of filter, a good HVAC company should be able to work with your existing system to get good filtration.  Period.

If you’ve never heard of MERV, it is an acronym that stands for minimum efficiency reporting value, developed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) in 1987.    The range is from 1 to 20, and designates with what efficiency the filter removes small particles between 0.3 and 10 micrometers in diameter. (check out this post for more information on MERV).   Generally you’ll want to get the highest rating possible (more filtration) for your system, without causing too much pressure drop, because in general, increasing the MERV increases pressure drop across the filter, while HVAC equipment manufacturers want you to stay with a low pressure drop of around 0.10 inches of water column (i.w.c.) across the filter.  That’s the tug of war–but why aren’t HVAC installers figuring out how to give consumers, the ones who pay for new or upgraded systems, both?  It’s like selling a delicious drink in a cup with a straw that’s too small to get it out at any satisfying rate (like a coffee stirrer).  Sure, you could take out the straw and lid and risk getting it all over yourself as you drink it.  However, even fast food chains and gas stations figured this out years ago: larger straw and cup= convenient way to drink, more satisfaction, more sales.

In this case, though, the consumer is left to bow to the advice of greedy or ignorant HVAC installers, or do research to figure it out himself.  Yes, there is a way to get both high MERV and low pressure drop!  You just need to install a larger filter.  It sounds simple, right?  Yet, because many installers are trained to recommend standard size, 1” filter frames, you’ll probably have to do the math and specify one yourself.  Don’t get scared yet!  We’re here to help with that calculation.  

Here’s a diagram of the typical HVAC system so you know what we’re talking about/aiming for:

Image source: RemoveandReplace.com

The part we’re talking about is outlined in blue.  The filter can be installed on the side of the HVAC closet door, in a ceiling or a wall.  In the diagram the air is flowing through the filter, up through the air handling unit, through the evaporator coil, and out to various room registers/grilles.  The whole system “sucks” air through that filter, and if it’s too small, it’s like sucking a Big Gulp through a coffee stirrer–the pressure drop or suction pressure is too much!  Making the “face” of the filter larger will allow the velocity of the air through the filter to drop, which makes the pressure drop go down.  

So, what is the magic size of filter that makes the pressure drop go down?  That depends on the size of your HVAC system.  This very helpful article from industry expert Allison Bailes gives the secret requirement:  

Filter Area = 2.0 square feet (or more) for each 400 cfm of air flow

Since most filters are measured in inches, we can convert that formula to:

Filter size (sq. inches) = System Air Flow(cfm) x 288/400    OR  

Filter size (sq. inches) = 0.72 x System Air Flow (cfm)

Like in any interesting math problem, this one has a formula with some knowns and some unknowns.  The unknown is the filter size, and the known is the System Air Flow.  To find the system air flow, you can do several things: 

• Look at the HVAC air handler information specifications.  If you don’t have the system specs, go to the air handler, take a photo of the sticker with the model number on it, and search for this model’s manual online.   For example, I replaced my air handler recently with a variable-speed unit.  It will shift fan speeds according to the heating or cooling load, with maximum 1200 cfm, 640 cfm intermediate, and 400 cfm minimum.  Since the pressure drop will be maximum at the maximum air flow, I’m going with 1200 cfm.
• Approximate the air flow using the system tonnage: cooling units are often measured in the US by “tons”.  According to HVACtrainingsolutions.net, 350 to 400 CFM per ton of cooling is required for proper air conditioning system operation. We’ll use 400 cfm to be conservative.  If you know you have a 3 ton system, then 1200 cfm is the maximum airflow.  This lines up with the specifications on my unit.  (This equivalent of 400 cfm per ton can vary because of relative humidity, dry-bulb temperatures, wet-bulb temperatures, air density, mass flow rate, and elevation; if you want to “get technical”, check out this article!)

After you determine the cfm of your system, plug it into the filter size formula above.  In my case, 1200 cfm x 0.72 = 864 square inches of filter.  Yikes!  My own filter (24”x24”) was undersized by a third, and when I measured the pressure drop at maximum fan speed (1200cfm) it was 0.25 inches water gage, which was fairly high for a clean filter. However, if I “upgraded” to a 24x36” filter that size fit my requirements exactly (864 square inches).  The problem is that I don’t have room for such a big filter.

If you find that space or filter availability for bigger filters is a problem, you can solve it in a different way: add another return with another filter.  Many homes have 2 returns, such as one upstairs and one downstairs.  In this way, you’re getting the area and the filtration you need.  Adding a second return lowers the airflow per return, and also changes the air circulation in your home.  At the minimum, high MERV and high airflow will not be a problem!  In my case, the easiest thing to do was look at the return air duct and add another grille in the only place I could: my bedroom.  I ended up adding a 20x20 return air grill there, which lowered the pressure drop to 0.09 inches water gage for a clean filter, which eased the work of the fan unit and gave me more filtration.

This is the dilemma homeowners often face: accept the “expert” opinion of their contractor, or start doing their own research and demand equipment or installations that at least safeguard the equipment they are installing!  Many installers mean well, but by not using standard equipment like manometers (pressure-sensing devices) they have no idea what the pressure drop over the filter is.  They also don’t know what pollutants like dust, human and pet dander, and microbes are allowed  into the new system by specifying low-grade MERV filters.  Their ignorance or bad advice costs homeowners BIG when the air, and consequently the system, stays dirty.  Just like we sometimes must do with our health and doctors, we hope that you take this information to your HVAC company and specify what you need to win the tug-of war and keep you and your family healthy!

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:

• The nasal mucosal pH is approximately 5.5-6.5, and increases in rhinitis to 7.2-8.3. (1999 study on NIH website)
• Saliva has a pH normal range of 6.2-7.6 with 6.7 being the average pH. (2013 NIH article)
• The normal values (of urine) range from pH 4.6 to 8.0, and a high urine pH may indicate kidney dysfunction or urinary tract infection.  A study even indicated that a urine pH of >7.5 is a single indicator of UTI. (Association between urine pH and common uropathogens in children with urinary tract infections)
• The pH level associated with the vagina plays a valuable role in determining vaginal health. The normal vaginal pH ranges between 3.8 and 5.0, which is moderately acidic (Vaginal pH Value for Clinical Diagnosis and Treatment of Common Vaginitis, 2021)

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 Healthline.com, “ 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)

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. (ChemistryTalk.org)  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?

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. (Britannica.com)  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!

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!

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. 

Volcanic Ash, Repurposed

Inferring from news headlines, you might think that volcano eruptions are rare–maybe a couple a year.  This is definitely not the case!  As of April 14, 2023, there were 49 volcanoes in eruption, 75% of them along the “Ring of Fire” where the Pacific Ocean meets land masses on the west and east.   To see the names and places of these active volcanoes, check out this page in the Smithsonian’s Global Volcanism Program.

Volcanoes emit several things when they erupt.  Gasses are composed of water vapor, carbon dioxide (CO2), sulphur dioxide (SO2), and hydrogen sulphide (H2S).   In actuality, lava can also contain 6% or more of its mass as gasses.  The gasses come out of solution from the lava when it erupts from the ground, in the form of bubbles or explosions.  (Volcanoes) Lava can flow in many forms above ground, below ground, and underwater.  The chemical composition of the lava causes it to have different viscosities and take different shapes as it cools and solidifies.  This page has a detailed description and fascinating photos of the many different types of lava.  

When gas and solids are emitted at the same time from a volcano–watch out!  Pyroclastic flows are the most dangerous type of eruption, where the hot pressurized gas can carry fragments of rock and ash for long distances.  Boulders can be thrown for miles if the eruption is particularly energetic, but the main danger for nearby residents is lava, fragments of rock called pumice, hot ash and gasses.  It was once thought that the residents of Pompeii perished due to suffocation of ash, but new evidence points to extreme heat.  (The Hazards of Pyroclastic Flows)

Clouds of ash can travel thousands of miles in the atmosphere.  It can disrupt airplane traffic and cause air pollution in distant cities, but when “the dust settles”, volcanic ash can be a good thing, as it’s used for many purposes.

Solid particles emitted from volcanoes are collectively called tephra.  Products made with tephra can be from ash (fragments of rocks, minerals, and volcanic glass ranging in size from sand to clay-like (from 2 mm to less than 0.004 mm in diameter) which is hard and abrasive), or milled/crushed from larger rocks and pumice.  Here are a few examples:

• Bricks made with 10-20% ash of Mt. Etna, a very active volcano in Italy, were less porous, more compact and less susceptible to decay, with a small loss of strength that was still in acceptable parameters. (Producing Bricks with Volcanic Ash from Mount Etna)
• Concrete made with 30-50% ash vs. 100% Portland cement is less energy-intensive to make and is stronger. (Cities of the future may be built with locally available volcanic ash)
• Volcanic ash can make soil incredibly fertile due to the different minerals it contains. 
• Volcanic rock can be used to purify water.  This use is discussed in the rest of this article.

Zeolites are natural volcanic minerals with unique characteristics. They are aluminosilicates, meaning that they are composed of varying quantities of aluminum, oxygen and silicon.  Zeolites were formed when volcanic ash was deposited in ancient alkaline lakes. The interaction of the volcanic ash with the salts in the lake water altered the ash into various zeolite materials, creating “pores”.  The pores have typical diameters of 0.5 to 0.7 nm, which are slightly larger than the diameter of a water molecule. Positive ions are present in the channels, which can be exchanged for other ions.

This substitution of ions enables zeolites to selectively adsorb certain harmful or unwanted elements from soil, water and air. A good example is the removal of calcium from hard water, also called "softening".  In this case, zeolites exchange sodium ions for calcium ions, which result in soft water. Zeolites also have strong attraction for certain harmful heavy metals such as lead, chromium, nickel and zinc. (Zeolites)

The oldest evidence of use of volcanic rock in water purification exists at Tikal, a Mayan city in northern Guatemala.  The Maya collected zeolite and quartz from a crystalline tuff (a light, porous rock formed by consolidation of volcanic ash.) about 30 km northeast of the city between ~ 200 BC and 1000 A.D. They used these natural volcanic mineral resources to purify large volumes of drinking water in a tropical forest environment, which was complicated by catastrophic cyclones, volcanic events, droughts, and subsurface drainage; this is the oldest known zeolite water purification system. (Zeolite water purification at Tikal, an ancient Maya city in Guatemala)

Zeolites can also be synthesized  from volcanic ash.  In an effort to reduce landfill disposal of the ash surrounding Mt. Etna in Italy, two samples of ash were processed to form a synthetic zeolite that could adsorb cesium (a radioactive element) from polluted water. (Synthesis of zeolite from volcanic ash: Characterization and application for cesium removal)

For those whose interests lie more in beauty products, volcanic material has moved beyond pumice stones used for foot exfoliation and now the ash is having a moment in skin creams, masks and primers.  The minerals in volcanic ash (including sulfur) are antibacterial, anti-inflammatory (when used temporarily and correctly) and some products can be used to exfoliate and dry especially oily skin.  Three dermatologists weigh in on volcanic ash’s skin-clearing properties in this article.

How can you use volcanic ash or zeolite around your home? (Zeolites-applications)

• For adsorbing odors: in shoes, carpets and kitty litter
• For absorbing fat runoff in barbeque pits
• For adsorbing moisture in closets and cabinets
• As a filter medium for your fishtank (adsorbs ammonia)
• As a filter medium for an air purifier (removes ammonia, formaldehyde, and other VOCs)
• As a filter medium for water purifiers and softeners
• As a garden soil additive for drainage, minerals and for landscaping textural interest

The minerals and rock formations of volcanoes vary endlessly in composition and uses.  Volcanic ash and zeolite are another of the earth’s natural filters and cleaners.   As our air and water become more polluted, we expect these resources to be used in many more ways–another example of taking “waste” and repurposing it for a cleaner environment.