All Posts by Jennifer Faul

How to repurpose common appliances into air purifiers

When you think of air purifiers, sometimes placement takes a role in the decision-making process.  Where do you place it? What if you could repurpose an existing appliance in your home and turn it into an air purifier, for double duty?

Ceiling Fans

Purifan has been in business since 1998, and the purifier industry has obviously exploded since then because of the coronavirus pandemic.  This company has found a way to convert your ubiquitous, ordinary ceiling fans into air purifiers.  There are many different kits available, but the basic installation involves removing the paddle blades from the ceiling fan, bolting on the Purifan’s brackets, and then attaching the Purifan.  The Purifan cleans and circulates more than 2,000 cubic feet of air per minute, which means it cleans the air in a 20′ x 20′ x 8′ room every 90 seconds.

If you don’t go with a Purifan, you can still use your ceiling fan to filter the air.  BioStrike is the maker of these ceiling fan filters, which remove a surprising amount of dust from the air!

Kitchen Exhaust Fan

This one only works if your over-the stove exhaust is operating in recirculation mode, not venting mode. Microwave/vent hoods have the option to recirculate inside or vent outside. In order to know what yours is doing, turn on your kitchen exhaust fan and place your hand above the door to feel if it is blowing air back into the room.   Although recirculating inside is not an ideal setup (because gasses from cooking/baking are being filtered and thrown back into the room instead of vented outside), you can make your exhaust fan do double duty and use it not only as cooking exhaust, but when you are not cooking, use it as an air purifier.  Charcoal replacement filters are available for many vent fans; here is how to replace them: 

• Check to see if your vent hood exhausts back into the room.  If not, don’t proceed with these steps as you will be only purifying air to send it outside!
• Remove the filter at the inlet to the exhaust vent hood (on the underside). 
• Measure and order new filters with charcoal in them.  Amazon has many of them, and you can search with your vent’s make and model number.
• Clean the filter thoroughly (here’s a video that gives 3 non-toxic ways to do it)
• While the cleaning agent is working on the filter, clean the surrounding  intake area of the exhaust fan. 
• Replace the filter until your new charcoal ones arrive. 

To make the vent act as an air purifier, run the exhaust fan several hours a day while you are not cooking in order to purify air in your kitchen.

Make a reminder on your calendar to change this filter at the recommended interval (or more often if you don’t cook a lot)!  Most charcoal filters are not reusable.  If you want to upgrade and change the configuration of your venting to outside, check out our post here.

Registers/Vents

Although using the vents as air purifiers requires the air handler fan to be set to always “ON”, this is a good move because it improves air circulation in the home, reducing stagnant air and the relative humidity of soft furniture (aka mold “food”).  Adding filter media to the registers can be very simple:

• Purchase bulk filter media, remove the vent cover, cut the media to fit, and reinstall the vent cover with media in it.
• Cool new diffuser covers with filters are also available. 
• If you are concerned with odors that seem to permeate the house, you can purchase bulk carbon filter media to use in the vents.

We all seem to be juggling several jobs at once, so why shouldn’t your home appliances do the same? 

How healthy is dry-cleaning?

We’ve all done it–accidentally machine washed and ruined a “dry-clean only” piece.  It’s so frustrating–what happens in the washer and why is dry cleaning “safe” for these items?  According to Rinse, a dry cleaning and laundering service, “Dry Cleaning can be beneficial for garments made from fibers that don’t react well when exposed to water, like silk and wool. It’s also good for garments that shouldn’t be exposed to the heat of a traditional dryer.”  It consists of pre-treatment to stains, washing in a chemical solvent that is free of water, spin-drying, post-washing stain treatment and press, steam or ironing to make all clothing look new again. 

In the 1800’s and early 1900’s, many kinds of petroleum-based solvents were used to wash clothes, because they remove stains better than soap and water, with less damage to the fabric.  Perchloroethylene (PERC) is one of several non-flammable solvents created to dry-clean during the petroleum shortage created by WWII, and it became the primary solvent used in the 1940’s through the end of the century.  However, it is discovered to be a respiratory and skin irritant, neurotoxicant, liver and kidney toxicant, and reproductive and developmental toxicant, as well as a probable carcinogen. (frontiersin.org)  Dry-cleaning machines using PERC have evolved to a 5th generation, which is a closed loop of washing, drying and recycling the solvent, so that operator and the environmental exposure to PERC is much lower than the 1st generation.  Despite these advances, residuals from the chemical in cleaned clothes and in the waste process are disturbing; the chemical will be outlawed in 2023 in California.   Alternatives range from n-Propyl Bromide (n-PB), which also has toxic effects, to high-flashpoint solvents, to the safest options, liquid carbon dioxide cleaning and Professional Wet Cleaning (PWC).  PWC uses good old water and detergent in a computer-controlled process.

As consumers, the dangers of residual dry-cleaning chemicals in our clothes may not be apparent, but they are there.  PERC vaporizes from clothing and is released into your home, according to a 2011 study.  Concentrations of PERC also increase as the clothing item is dry-cleaned several times, except for silk, which does not retain PERC.  If several dry-cleaned items are left in your car, levels of PERC can rise well above permitted levels by OSHA for workplaces using the chemical.  This suggests that those who deliver dry-cleaned clothing might have more exposure than even those who process it.

In 2021, 90% of dry-cleaning shops in France still use PERC, and estimates in the US may be as low as 65% (vice.com)  Kings County, Washington has been especially proactive in helping cleaners to switch to PWC.  Education on the machines and the process, as well as financial assistance to purchase new PWC machines has been key to the transition.   It’s certainly a looming deadline for California shops, but Minneapolis already forced the transition and became PERC-free in January 2018 (americandrycleaner.com)

Dry-cleaning has been in a slight decline because of the coronavirus pandemic (less in-office work days with less formal dress) and the development of fabrics that can be successfully laundered at home.  Still, if you don’t live in Kings County, WA, California, or Minneapolis, what can you do to reduce your exposure to PERC?  Here are some suggestions:

• Familiarize yourself with how to hand wash delicate items, and it may eliminate most of your dry cleaning!  Take these tips from Town and Country Magazine.

• If you do go for dry clean, air the items out of their bags in a ventilated space away from your home, like the open sunshine or in a carport. 

• Investigate cleaners that use PWC instead of PERC.  Rinse.com is a delivery service that offers laundry, fold and dry-cleaning to areas in California and New York, and states that none of their cleaners use PERC, however not all of them use PWC because they don’t recommend wet cleaning for all items.  It may be a case of calling and asking “I have this item” and “what can/would your shop use to clean it”?

• Be wise in purchasing new clothes–avoid “Dry Clean Only” when you can.  “Dry Clean Suggested” is a more flexible option, but “Hand Wash” and “Machine Wash” are definitely preferred!

How healthy is your SprayFoam?

Sprayfoam has been a huge player in the home insulation industry, and is projected to grow by 4-6% CAGR through the next decade (marketsandmarkets.com).  It is used as insulation (R-3.8 for open cell and R-7 for closed cell), and can be an air barrier and/or vapor barrier when applied properly (Johns Manville).

Bud Offermann is President of Indoor Environmental Engineering, a building science consulting firm in San Francisco.  He gave a very informative interview on healthyindoors.com in July of this year, on material from a paper he presented at the International Society of Indoor Air Quality and Climate’s (ISIAQ) Indoor Air 2022 in Kuopio, Finland in January.  You can read and download the paper here.   Because of his experience with high variability in the application of spray foams and ensuing problems with chemical emissions, he can’t recommend spray polyurethane foam (SPF) to insulate your home.  This article is based on his presentations.

Some SPF installations result in chemical emissions that cause odor and irritation and that are expected to persist for decades.  Therefore, it’s important to research and consider before contracting for spray foam insulation. Can you imagine ruining your well-loved or newbuild home with something as permanent as spray foam?  

There are two components of spray foam, which we can term A-side and B-side.  These are stored in two different containers and fed through two hoses to the spray gun, where they are mixed as spraying takes place. The A-side is isocyanates, which are very reactive; they evaporate quickly and don’t hang around after application.  These chemicals are mainly a problem for the applicators, who need to wear fresh-air breathing apparatus to avoid breathing them.  The B-side is a resin which has the fire retardant, reactants and additives.  These are the components that remain in the installed foam and off-gas over a period of time. 

The main chemicals causing problems are allylchlorides, the fire retardant TCPP, BDMAEE (an amine created by breakdown of TCPP), and 1-Chloro-2 Propanol.  These can cause eye and nose irritation.  The emissions can last at a slow rate for 50-100 years.  Temperature causes an increase in irritation and odor (summertime is worst). 

Causes of offgas problems are hypothesized to include:

• If the two components are mixed in the wrong concentration, it will not cure properly.  For example in closed cell foam, too much A makes the foam fragile and brittle.  Too-much B makes the foam too gooey. 
• Storage of the resin (B) in the warehouse possibly allows water contamination (hydrolysis of the TCPP).  Addition of water can create 1 Chloro-2 Propanol or allylchlorides.   These substances can cause allergic reactions and continue to occur months or years later as the foam off-gasses.
• Closed cell foam should not be installed in thicknesses greater than 3”, otherwise the interior of the foam layer will not cure.  Multiple passes are needed to achieve thicker application, but sufficient curing is needed between layers, otherwise uncured foam inside the layers will continue to off-gas. 
• Sometimes the applicators switch between open and closed cell foam without changing the transfer pump or hoses.  They only change the B-side (resin) drum and start spraying, which makes the product in the pump and hoses an unproven mixture of open and closed cell.
• Sometimes applicators buy the B-side and then add more chemicals for “winterizing” the foam.  This is adding chemicals after-market, which will invalidate any warranty on that foam.

If you are experiencing bad air quality after spray foam application in your home, the first step is to test.  Testing will let you know the level of the problem and if litigation is needed, proper air testing is required.  Air samples are gathered with windows and doors closed, supplemental attic ventilation turned off, no air cleaners running, and normal house HVAC running. There are specific chemicals to test for, including VOCs excluding isocyanates and formaldehyde, also samples should be gathered in different rooms and outdoors as a baseline.  After the air is sampled, an 8x8” chunk of foam is removed without disturbing the surface of the foam, to send to the testing facility (Berkeley Analytical is one recommended lab).  You should also get the material safety data sheet (MSDS) for the foam, which should disclose all non-proprietary ingredients.

If emissions of SPF continue to cause problems, as an expert in home inspection and remediation, Mr. Offermann states there are two solutions: 

• remove the insulation and the substrate, because the substrate absorbs some of these chemicals (very costly) OR
• attach a foil faced gypsum or rigid foam board against the trusses/studs to contain/reflect the gasses. 

If you are sensitive to chemicals, spray foam is probably not the best choice for your home.  However an alternative is to use foil-faced foam board.  Because the foam board is made in the controlled environment of a factory, then tested, you can get the same insulative properties with much less chance of continual off-gassing .  Foam board doesn’t have air barrier properties because of the way it’s installed, but air barriers can be achieved with other non-chemical methods.

In conclusion, further research on the chemical reactivity of TCPP and its suitability as a fire retardant is needed.  Where is hydrolysis occuring?  Proper storage of the B-side product and training of the application team is necessary because once spray foam is applied, emissions are unhealthy and removal can be very costly.   

Wall covering products that resist mold and mildew

When my kitchen faucet caused a leak under the sink and mold spotted the drywall behind it, I thought, with what material can I replace the drywall to make it less mold-friendly?  Under the sink is a dark, damp area where water can intrude again.   Searching my local big hardware store, all I came up with was fiberboard that had a melamine coating on one side.

Doing some more research online, however, uncovered several more options.   These are not only for under sinks, but garages, basements, utility closets, porches, and anywhere that moisture can be an issue.  

Using large panels instead of smaller cladding units (tiles, boards, etc.) minimizes labor, opportunities for water ingress, and also dust, which is always an inhalation hazard for the installers and anyone else in the area.  

Interior Cladding

Trusscore is a new PVC product that not only resists moisture, it reduces installation time, labor and cost when compared with drywall.  Trusscore panels are ½” thick, so that they are the same thickness as drywall.  They are so named because of the truss-like structure inside to give them strength with flexibility (they bend enough to facilitate installation inside channels without creasing).  Once you see this product being installed, who would ever want to go back to the labor intensive, dusty, mold-prone drywall process again?  I really like the clean simplicity of this product.  My major concerns with having it in residential spaces were:

• VOCs and off-gassing: how much harmful pollutants will it pass into your indoor air?
• Penetrations, because inevitably, someone will want to hang a picture or shelf on it, and then you have visible, difficult to patch holes in it.  
• What about changing the color? 

However, the company has integrated solutions into each of these problems.  

• Trusscore addresses IAQ here: “Trusscore Wall&CeilingBoard, RibCore, and NorLock products are all low-VOC compliant, including low formaldehyde, meaning it won’t off-gas and ensure a safe and healthy space for occupants. In addition, the installation of Trusscore products does not require potential VOC sources like glue or paint for a finished installation.  Each product has been tested according to the California Department of Public Health (CDPH) Standard Method v1.2 testing standard. This is the leading VOC standard used to evaluate VOC emissions from building products such as flooring, suspended ceilings, insulation, wall panels, paints and coatings, and wall coverings. The CDPH standard is referenced by some of the most widely used green building rating systems and green construction codes including USGBC LEED, CalGreen, and more.”  Still, in a fire, I would RUN out of any area that was covered in PVC...I’d say this is definitely not the material to cover any space where welding or high heat hobbies occur.  Also, I would hesitate install to it in high ambient heat places like Las Vegas or the southwest US (it’s plastic, after all)!  
• Trusscore makes slatwall, which makes it easy to hang things (especially useful in garages and utility rooms)
• All the panels come pre-finished in a durable white or gray coating, and painting guidelines can be found here (Painting requires special primers so that the paint will stick).  The benefit of painting: if you can paint it, you can also patch it!

Duramax PVC Wall Panels are very similar to Trusscore, but they come in 16” widths instead of 48” widths.  They also do not have any slatwall systems, recommending instead to use hangers similar to drywall hangers to permanently hang anything.  The cost of Duramax is less than Trusscore ($2.70/sf vs. $3.60/sf). They do not have any VOC emissions information on their website or MSDS other than protection guidelines against dust generated while installing it.

MSD panels have a variety of natural and futuristic textures (brick, tile, wood, stone, etc.) for a moisture-resistant cladding for interior walls.  The video on this page contains a little bit construction, a little bit artistry as the installers hang the panels and patch the seams to make the brick wall look completely congruent. As an artist, I do like these for the realistic looks they form.  Unfortunately, they are in Spain!

EverBlock and EverWall products are like giant Legos (with these why would you want to “grow up”?).  Everblocks are made of High-Impact Polypropylene Co-Polymer (“no-break”) with UV Inhibitors added for outdoor use.  EverBlocks are recyclable. They don’t offer much insulative quality (R-2 equivalent), but they are hollow and internally reinforced.

Formica lives on!  Formica HardStop has the great variety of colors and patterns of traditional Formica, but instead of the traditional fiberboard backing that is susceptible to moisture ingress, HardStop has a fiberglass backing that makes it more durable and water-resistant. It can be applied to drywall, plywood, and particle board (which are susceptible to water) or to cement or cement board. HardStop panels are thin and flexible like the original Formica, so they do need a structural element for reinforcement behind them.  They also require adhesive (looks messy to me!).

DriCore Smartwall is a similar system that incorporates an insulated layer on the back of the panel.  Very genius, however, the system uses drywall in the panels, and wood cleats to install it and has wood interlocking sections within the panels.  Here is a video on the installation of DriCore Smartwall, which also uses patch material to make a seamless wall.

Exterior cladding

The more I read about building science, the more I see imperfections in “the way we always did it”.  There are many traditional finishes for commercial and residential buildings, but the gold standard calls for a “rainscreen” type structure that applies the cladding to a hidden track system, so that air can reach behind the rainscreen and dry things out.  Think about a rain fly for a tent, or a double roof system.  The air buffer separates water and extreme heat or cold from the exterior of the house, making for a longer-lasting house!  In his article “The Perfect Wall”, building scientist Joe Lstiburek defines the elements of this wall and how they are constructed to resist rain, snow, humidity, air intrusion, mold, heat and cold, etc.

Here are some products that work as rainscreens:

• Nichiha: this company was founded in 1956 in Japan but now has an office and factory in Georgia.  Their cement fiberboard siding comes in architectural panels or premium planks and uses a hidden track system.  It is an upgrade to “Hardy Board” and the many imitations of it, because it “floats” on the track system with that air buffer behind it.
• Ceraclad is a triple-coated ceramic and cement rainscreen with its own installation system. The panels are self-cleaning, with a photocatalytic coating that actually purifies the air!  The coating decomposes car exhaust and other pollutants in the air (NOx and SOx) and turns them into NO3 harmless polyatomic ions leaving the air cleaner.  According to the website, a building with 10,000 sf of external Ceraclad coating is the equivalent of 68 poplar trees!  10 Ceraclad panels are the equivalent purification to 1 poplar tree.  The coating also inactivates viruses and bacteria at its surface. 
• Knight Wall Systems provide the hidden tracks to install your rainscreen.  They have three different types of attachment to accommodate many different types of cladding.  Although mainly commercial, this system could be used for high-end residential homes as well.
• Monarch Metal offers cladding systems with all kinds of finishes including HPL Phenolic, stone, fiber concrete and more.  Their hanging system contains high quality “Z-clips” which are similar to french cleats that allow you to hang the facade without screwing into the face of it, also interlocking panels as you install them.

These are just a sample of ways to get less mold growth in damp areas, relying on 1) materials that don’t sustain mold and 2) siding that incorporates ventilation.  It’s building science at its best!

What are Endotoxins and Exotoxins and where do they come from?

The word “toxin” causes my ears and eyes to perk up, because these are the types of substances that cause illness and even death.  Thankfully, it is increasingly possible to avoid toxins by understanding where they live and how they’re spread.   Science is advancing very rapidly to show us how to manage our environments, food, lifestyle and even our bodies to live more healthfully.   Endotoxins come from Gram-negative bacteria, and Exotoxins can come from either Gram-positive or -negative bacteria so we’ll start with what the “Gram” test means. 

Bacteria can be classed into two different groups: “Gram-negative” or “Gram-positive”.  These classes are based on a test developed by scientist Christian Gram in 1884, which differentiates the bacteria using a purple stain.   According to webmd.com, bacteria either have a hard outer shell, or a thick, mesh-like membrane called peptidoglycan.  The hard outer shell will resist the purple stain, and show up as a red color.  These are called “gram negative” because the purple stain did not show.  Bacteria with the peptidoglycan absorb the purple stain much more easily and are called “gram positive”.  The stain also tells more characteristics about the bacteria and the way it interacts with treatment. 

The peptidoglycan layer of Gram-negative bacteria is much thinner than that of gram-positive bacilli; instead Gram-negative have a hard, protective outer shell, making them harder to kill because of their harder cell wall.  When their cell wall is disturbed, or the bacteria are dead or dying, gram-negative bacteria release endotoxins that can make symptoms of illness worse.  In contrast, exotoxins are produced inside the bacteria and may be released while the bacteria cell is living, or during its death.

Here is a diagram that shows how the exo- and endo-toxins are released (source: microbiologyinfo.com).  (I distinguish them by remembering that endotoxins are only emitted at the “end” of life of the bacteria):

Here are some examples of gram-negative bacteria diseases (webmd.com):

• Vibrio cholerae (Cholera, a serious intestinal infection)
• E. coli (E. Coli infection)
• Yersinia pestis (Plague, an infection of the lymph nodes and lungs)
•  Bartonella henselae (Cat-scratch disease)
• H. Pylori (gastritis, peptic ulcer disease, gastric lymphoma, and gastric cancer)
• Campylobacter (campylobacteriosis, an infection that usually affects the digestive tract)
• Legionella bacteria (Legionnaire's disease, a lung infection)
• Salmonella (salmonellosis, a digestive infection caused by contaminated food)

Here are some Gram-positive bacteria (and the infections they cause): 

• Staphylococcus aureus (MRSA, toxic shock)
• Streptococcus group A (strep throat, toxic shock)
• Clostridium botulinum (botulism)
• Bacillus anthracis (Anthrax) 

As you can see, endotoxins and exotoxins are a serious matter!  Here are some of the other important differences between them (byjus.com):

(A toxoid is a chemically modified toxin from a pathogenic microorganism, which is no longer toxic but is still antigenic and can be used as a vaccine (Oxford languages).)

There is so much to study about bacteria, however since we at HypoAir mainly focus on air quality, we’ll try to limit this post to the toxins that can be transmitted through the air.  

Endotoxins (Endotoxins: Small But Very Significant):

• Are pyrogens, that is, they often cause a pyrogenic reaction (fever).

• Cause fatigue, a common characteristic of sick building syndrome. 

• Don’t produce immunity, but only a temporary resistance known as “Monday fever”. Workers in industries with significant endotoxin levels have been found to be most afflicted on Monday, with reduced effects through the week. Endotoxin resistance is lost over the weekend, with the illness beginning anew the following Monday [5]

• Are “adjuvant”, meaning that they can amplify the effects of other harmful substances. 

• Are associated with sepsis, an extreme immune response by the body that often ends in death.  

• The presence of pets in indoor spaces can represent an important source of air contamination and can be linked with the level of indoor endotoxins. The presence of dogs and cats can be the main predictors of endotoxin levels in house dust [1, 4-7]. Other predictors are the presence of vermin, such as mice, and infrequent cleaning, which indicates poor hygienic conditions in the home [1]. Storage of organic household waste indoors also increases bacterial contamination in the indoor environment [1]. (intechopen.com)

Here are some more details about endotoxins.  Although it’s a little in-depth, this article gives a good explanation of what endotoxins are and how they are released (shed) from bacteria.  Basically, endotoxins are small molecules of lipopolysacchride (LPS), which comprise approximately 70% of the outer membranes of gram-negative bacteria. They are responsible for maintaining structural integrity and have been shown to be essential for bacterial survival.  Lipopolysacccharides vary in their structure, but all share three distinct regions:

• O antigen repeats are found on the outermost domain of the LPS molecule and are responsible for host immunogenicity (the ability of the endotoxin to provoke an immune response in human cells).

• Core domain is composed of sugars and other non-carbohydrates.

• Lipid A is the lipid component of LPS, whose hydrophobicity (repels water) facilitates membrane anchoring. Lipid A is responsible for toxicity of the endotoxin.

Here is a diagram of this structure:

Source: What are endotoxins?

Endotoxins are naturally shed at low levels during bacterial growth, but are released in much larger quantities upon cell death when their cell membranes rupture and disintegrate.  A single E. coli cell can release up to 2 million LPS molecules!  As lipids, endotoxins are naturally hydrophobic, which gives them a strong affinity for plastics and hydrocarbon-based materials (vinyl flooring, polyurethanes and coatings on many new products).  

The Limulus Amebocyte Lysate (LAL) test detects endotoxins.  It comprises blood cells (amebocytes) from the Atlantic horseshoe crab (Limulus polyphemus) that clot when they encounter bacterial endotoxin lipopolysaccharides.  The LAL may be used to test in three different ways: to provide a yes/no (qualitative) answer to whether a sample contains a specified amount of endotoxin, or to obtain the quantity of endotoxin via how fast the clotting takes place (turbidimetric) or how intensely the color changes (chromogenic). (Bacterial Endotoxins Testing)  In the qualitative test, equal amounts of a test sample and the gel clot LAL are mixed in a test tube and incubated at 37 °C for 60 minutes.  After the incubation, the tube is inverted.  If sufficient endotoxin is present in the test sample, the solution would have clotted during the hour incubation and a gel will remain in the bottom of the inverted tube (see image below).  If the sample does not contain detectable endotoxin, no clot will form and liquid will run down the side of the inverted tube.  (LAL/TAL Endotoxin Detection Test Methods)  The enzymatic reaction between the endotoxin and lysate produces a yellow color, the intensity of which is directly linked to the quantity of endotoxin present in the sample.   

How can we reduce exposure to endotoxins?

• Reduce Dust: According to EMLab, a commercial IAQ laboratory in North America, “ Endotoxin exposures are mainly through the air.”  “Endotoxins do not float freely, but instead are attracted to dust particles. Reduction of dust is essential for controlling endotoxin levels. Dust reduction requires both fresh air filtration and filtered air recirculation. Continuous, low flow fresh air ventilation systems without recirculation do not effectively manage indoor particulates. Endotoxin levels and dust levels are not strongly correlated indicating that they come from independent sources. A single dust particle in the 2 to 10 micron range has sufficient surface area to hold a million or more endotoxin molecules (approximately 0.1ng of endotoxin). Therefore, reduction of dust is important regardless of whether one lives in a dusty or relatively dust-free environment.” (this and following points from buildequinox.com).
• Removal of food sources: “Coupled with proper ventilation is reduction of source generation of endotoxins. In the home environment, it is clear that kitchens are one source of endotoxin generation. Removal of food wastes and standing dishwater will reduce bacterial growth with subsequent production of endotoxins. Even a bowl of standing water will grow bacteria in a home. Bacteria and nutrients are ubiquitous indoors and outdoors, and they will land in water or moist regions where bacterial growth will occur.” Kitchens have the highest level of endotoxins, followed by living rooms and bedrooms.
• Avoid use of misting humidifiers: “Cold temperature (misting) humidifiers are strongly linked to high endotoxin levels. Vaporizing humidifiers that heat water to boiling have not been found to produce high levels of endotoxins.” An alternative method for achieving sanitized, cold temperature humidification in a home is through plant transpiration. Plants can reduce toxins in homes [12]. The plant-root matrix releases sanitized water into the air (assuming proper plant care that does not form a wet mass promoting fungal and bacterial growth).

Exotoxins are (from textbookofbacteriology.net unless otherwise noted)

• part of a defensive system of bacteria to avoid capture and killing by leucocytes (part of our body’s immune system). (sciencedirect.com)
• Produced by both Gram-negative and Gram-positive bacteria 
• More highly poisonous by mass than endotoxins, strychnine, or snake venom 
• Can be “super-antigenic” or cause stimulation to the immune system 
• are often encoded by mobile genetic elements, including bacteriophage (phage). Phage can transfer genetic information to the bacteria they infect. (study)
• Can produce illness even when the microbes that produced them have been killed. (skybrary.aero)

What are the sources of exotoxins? (from intechopen.com)

• Actinobacteria (especially Streptomycetes), Bacillus species and various other bacteria grow in moist building materials together with fungi. Elements from bacterial structures released in air include bacterial cells, bacterial spores, peptidoglycans, microbial volatile organic compounds, exotoxins, and other bacteria growing metabolites.
• Gram-positive bacteria with exo- and endospores like Streptomyces and Bacillus can grow on moist building materials. Their spores are very resistant and can survive even if the air humidity is low.
• Humans are an important source of indoor bacteria. The upmost layer of the normal human skin is continuously renewed, and skin scales containing bacteria are shed into the environment. Bacteria in the respiratory airways are eliminated through Pflügge droplets while talking, coughing, or sneezing. The level of air contamination is dependent on the number of persons inside a room and the efficiency of the ventilation system (natural or artificial ventilation). Bacteria that can be identified in indoor air are micrococci, staphylococci, streptococci, and corynebacteria.

How can we reduce exotoxin exposure?

• Maintain your home so that there are no active leaks and humidity stays between 40-60%.  This will reduce actinobacteria that produce exotoxins.
• Practice good hygiene by covering your mouth and nose while coughing or sneezing.  This reduces the amount of small particles in the air that can contain bacteria and exotoxins.  Dispose of tissues in the trash and wash hands with soap and water. 
• According to the WHO, if exposure to the toxin via aerosol inhalation is suspected, additional exposure to the patient and others must be prevented. The patient's clothing must be removed and stored in plastic bags until it can be washed thoroughly with soap and water. The patient should shower and be decontaminated immediately. 
• Most exotoxins can be destroyed by heating, (wikidoc.org), so eating thoroughly cooked food often eliminates the danger of ingesting the exotoxin. The WHO recommends these five strategies in food safety:
  • keep clean
  • separate raw and cooked
  • cook thoroughly
  • keep food at safe temperatures
  • use safe water and raw materials.

Use of a HEPA filter can reduce aerosols and fine particles containing bacteria, endotoxins and exotoxins, although some of the smaller phages may slip through.  This is where a healthy immune system and abstaining from smoking pick up.  Cigarette smoking is a substantial risk factor for important bacterial and viral infections. For example, smokers incur a 2- to 4-fold increased risk of invasive pneumococcal disease. (2004 study).  In addition, exposure to cigarette smoke causes MRSA bacteria (just one bacteria studied) to become even more resistant to killing by the immune system. (UCSanDiego Health News)  Of course, smoking through a dirty water pipe (bong) is inviting disaster!  Here are the details (mooselabs.us):

Bacteria, endotoxins and exotoxins are all around us (and even in us), but with good judgment and  precautions, you can avoid being one of the infection statistics!

What is Inverter Technology and what does it do for my Air Conditioner?

To start, let’s review the way conventional air conditioners work.  You set your preferred temperature, and when the room gets too warm, a thermostat sensing the higher temperature will cause the air conditioner to come on.  When the room is cooled properly, the air conditioner shuts off.  The lag in turning on and off varies by unit, but it can be as much as two-three degrees:  at a set point of 72 deg F, the air conditioner doesn’t come on until the room warms up to 73, and doesn’t shut off until the room is cooled to 71 deg F or lower.  In the case of inverters in air conditioners, they can keep the room at an even 72 all day long by running continually with lower power input.  The best way to explain them may be the example of cruise control in a car.  If you try to keep the car at a steady speed, you’ll need to depress the gas pedal when you see the car decelerating, and let up when it goes over your target speed.  Letting the car’s computer keep the speed is actually more gas efficient, because it will sense speed fluctuations sooner, and meter the gas pedal more accurately than you can!  Here is a pictorial by Panasonic:

Once again, the power of computers is making our lives better by modulating the power consumption of the unit and avoiding those annoying temperature swings.   But wait–there’s more!  With only a 2-3 degree temperature swing with a traditional air conditioner, why does it feel like one minute you need an iced drink, and the next you need a sweater?  It just doesn’t seem like that should happen with only 2-3 degrees. The answer lies in the humidity of the air.  Temperature fluctuations cause the relative humidity (RH) to fluctuate, which makes a big difference in comfort levels!   Humidity gets taken out of the air as it passes over the evaporator coils, and this is an important function of the air conditioner, because as you cool the temperature, RH will go up.  If you don’t have a non-inverter air conditioner sized just right (having the optimal compressor power and refrigerant for the size of room), it will run for too long or too short, causing the RH to fluctuate:

• Too large of a unit means it will run for short cycles, cooling the room quickly but not running long enough to remove adequate moisture from the air.  
• Too small of a unit means that it will run for long periods of time and humidity will go down, but jump right back up when the unit shuts off.

The inverter air conditioner not only keeps temperature constant, it can also keep humidity lower and constant.  Here’s how that works:

• Back to physics class:  There are two kinds of heat: sensible and latent heat. Here is an excellent page to understand more, but basically sensible heat is related to changing the temperature of a body (in this case the air), and latent heat is related to the phase change of the body (in this case changing the water vapor in the air to liquid so that it will drain away).  
• Constant speed on/off systems are good at removing sensible heat to lower the temperature of the air.  However, they don’t do such a great job at removing latent heat (humidity) out of the air.  This diagram shows why: it is a diagram of how much energy is needed to push water into a different phase.  The long flat part at 100 deg C (212 deg F) shows how much energy is needed to change water from liquid to vapor, and once it is a vapor, the same amount of energy (970 BTU, or British Thermal Units) is needed to condense it back to a liquid, without even changing the temperature!

• So, when the system is set to only lower temperature, it does not continue to supply the needed energy to change the phase of the water vapor in the air to a liquid, to condense it out of the air.  It will simply stop cooling when it hits the temperature set point.
• Inverter technology uses a computer and variable speed fan to slow down the speed of the air crossing the evaporator coil.  When the air spends more time in the evaporator, more water vapor will condense out of the air, meaning more dehumidification occurs.    It also uses a variable speed compressor to better control the flow of refrigerant through the system, because slowing the fan alone with a standard compressor may cause the coil to freeze.  Since the system will be continually cooling instead of stopping and starting, a variable speed compressor allows for a small steady flow of refrigerant when the room is in a steady state (no one coming in or out or cooking, etc.), but also a ramp-up when someone opens a door or turns on an exhaust fan, etc. 

This is all great information, but what if you have a central AC system that’s only a couple years old, and very little budget to go making changes?  The good news is that it is possible to replace your standard single-speed blower motor with a variable speed motor.  Here are some facts about this type of upgrade:

• The term “variable-speed” applies to two different components in an air conditioning or heat pump system: the blower motor and the compressor. A variable-speed blower can be matched with a single-speed compressor, but a variable-speed compressor must always be paired with an adjustable-speed blower. (therma.com)
• Single speed motors in blower units are generally called “PSC” or Permanent Split Capacitor, while variable speed motors are called Electronically-Commuted Motors (ECMs) or Brushless Permanent Magnet motors (BPMs).  ECM is a trade name for BPM (BuildingScience.com)
• ECMs come in “3 flavors”: non-variable constant torque, variable constant torque, and variable constant flow.  (David Butler, energyvanguard.com).  If you are looking for better dehumidification, you may want to go for the Variable speed, constant torque model.  The Variable speed, Constant Flow models are the most expensive.
• ECMs are quieter and use less electricity than PSCs.
• Retrofitting the blower fan has the following challenges:
  • You’ll need to make sure the existing electrical service is compatible with the new ECM.  Although the resulting operating current draw should be less than the PSC motor it replaced, you’ll need to check that the motor nameplate ratings don’t require upsizing the supply circuit in order to provide the necessary electrical safety.  (Titus HVAC)
  • The new motor may require a different type of mounting, ie. a “belly band” vs. a bracket, and the technician may need to use parts from several conversion kits to install it. 
  • The Building America program retrofitted PSC blower motors with ECM motors at 8 homes in upstate New York in 2013 as part of a study.  The study did extensive screening of homes and systems so that only homes with the right size hp motors, the right size blower housing and cabinets, and the right type of motor mounts were chosen, making the install straightforward for the technicians (US Dept. of Energy).  According to Titus HVAC, ECM retrofit doesn’t just mean replacing the motor. It generally means replacing the motor, the speed control, and blower assembly. It will likely also require additional components like power cables, communication cables, and a power filter. It could even require changing internal options like line and/or motor fuses.  
  • There are several manufacturers for these retrofit motors.  
    • The most well-known may be Regal Rexnord with the Genteq Evergreen motors, also offered on Amazon (this company purchased the ECM trade name).  
    • US Motors’ “HVAC Rescue Motors” series includes bluetooth-enabled motors and some that do not need the aforementioned airflow programming, making for an easier install.
    • The Concept 3 motor used by the Building America Program is currently out of production.
  • A knowledgeable HVAC technician can help you with the decision and options; don’t be afraid to get several opinions!  Ask if he will be taking pressure and power readings before and after the install.  This is key to getting your new motor running right, or preventing an ineffective change to the system.  Here are two links for more information on pressure and power draw readings.
• Some states or power companies may offer rebates to retrofit your PSC with an ESM, such as this 2013 offer by Minnesota Power. 
• ECMs will save power on systems that are set to have the fan always “On”, such as when a Whole-Home Polar Ionizer is installed.  This type of purifier runs 24/7 and as such needs the fan to run 24/7.  

If your whole HVAC system is nearing end of life (10 years or more), you may ask about replacing the blower and compressor with variable-speed units, which will give the best energy efficiency available in forced air units today.  Some HVAC companies will try to sell what is easiest for them to install, or what their suppliers recommend, or what has always been done, but there is always room for improvement…keep searching and asking until you find it!

It’s not the heat, it’s the humidity air pollution!

Decades ago, when the meteorologists predicted extreme heat, it seemed they only advised on the necessity to stay out of the sun, drink more water, and cool off more frequently (stay in the pool, yayyyy!).  Now, heat advisories come with more sinister warnings about air pollution levels, and the outdoors are less fun.  How did that happen?  The answer lies in meteorology and chemistry, all cooked up in our atmosphere.

Low-pressure systems are quite famous for moving rapidly across the US and bringing devastating weather like severe thunderstorms, hail and tornadoes.  They can also sweep pollutants like smoke and smog to other states.  High-pressure systems, on the other hand, typically cause stagnant air, which can concentrate pollutants over one area.  (scied.ucar.edu)  A “Heat Dome” is an area of high pressure that parks over a region like a lid on a pot, trapping heat. (National Geographic) A Heat Dome caused about 600 deaths in June 2021 in the Pacific NorthWest as a 1-in-1000-year event.  The heat, which broke Portland’s all time record of 107 degrees, was bad enough, but extreme heat combined with stagnant air during a heatwave increases the amount of ozone pollution and particulate pollution. (metone.com)  Here is where the chemistry comes in.

“Ground-level ozone pollution forms when heat and sunlight trigger a reaction between two other pollutants, nitrogen oxide and volatile organic compounds — which come from cars, industrial facilities, and oil and gas extraction. High temperatures therefore make ozone pollution more likely to form and harder to clean up. Drought and heat also increase the risk of wildfire, which can make air quality worse as smoke drives up levels of fine particulate matter — also known as PM2.5, or soot...Both ozone and PM2.5 carry major health risks. Ozone can cause acute symptoms, including coughing and inflamed airways, and chronic effects, including asthma and increased diabetes risk. PM2.5 exposure can lead to an increased risk of asthma, heart attack, and strokes. Globally, long-term exposure to PM2.5 caused one in five deaths in 2018, including 350,000 deaths in the United States.” (Heat waves can be life-threatening for more reasons than one)

Because of the increase in cars and industry, extreme heat forecasts are not just requirements to have bottled water and popsicles on hand and check that our elderly neighbors’ air conditioning is working.  It’s a time to make sure that those who have asthma, heart and vascular conditions stay indoors, and that you take the proper air pollution precautions, too. 

Unlike outdoor air filled with wildfire smoke, ozone and smog are not as visible and may not affect everyone immediately, but they are dangerous pollutants and shouldn’t be allowed in our homes.  Here are some steps you can take to prepare for that heatwave, and the resulting air pollution that often accompanies it!  

• Seal doors and windows with weatherstripping, caulk and door sweeps.  

• Find out how to adjust your HVAC system accordingly: you’ll want to close the fresh air intake and change over to recirculation, no matter whether you have central AC, a window air conditioner or portable air conditioner.

• Purchase extra MERV 13 filters for your HVAC system, to be used on poor air quality days (caution: read our post on HVAC filters first, as using a filter with too high MERV rating can damage your system). 

• If you live in an apartment building or condo with little control over the HVAC, consider purchasing vent filter material so you can place them in the vents into your space.  The filter material can prevent smaller particulates in smog from entering.  Carbon vent filter material will neutralize many VOCs as well.

• Purchase a HEPA air cleaner (non-ozone producing type) and be sure to have an extra filter or two on hand.  The use of a HEPA filter will take much of the damaging fine particles out of the air you breathe!  Whenever there is bad air quality outside, run the cleaner/purifier on high for an hour and thereafter at "quiet"/medium setting (Wirecutter).  You can check out our post on standalone HEPA filters as a purchase guide.  If you can't purchase one, make one: there are many videos and instructionals online for DIY air cleaners; most only require one or more filters, a box fan, and some cardboard and tape.

• Keep a stash of N95 respirator masks on hand.  These are a good source of protection if you have to go outside, or if power is cut to your home and indoor air quality gets bad as well.  The “95” means it blocks out 95% of particulates.   

• Keep canned and non-perishable food on hand, so that you don’t have to cook during periods of bad air quality.  Cooking indoors increases small particulates and vapors in the air, and you won’t want to turn on your stove exhaust, as that will draw polluted outdoor air into the house.

• If air quality is very poor (check next point), you’ll want to evacuate to a place with clean, filtered air, like indoor malls, libraries, community centers, civic centers and local government buildings (sfgate.com). 

• Check your local air quality and receive updates from airnow.gov . Using an Air Quality Index (AQI) as a measuring tool ranging from 0-500, your local forecast and larger maps can be color coded to show whether an area is good (green), moderate (yellow), unhealthy for sensitive groups (orange), unhealthy (red), very unhealthy (purple), and hazardous (maroon).

Protection from Over-Chlorination

When I think about the pool where I learned to swim, I can almost smell the chlorine!  It was a YMCA where one half of the building had a “giant” (to a 5-year old) pool with lanes divided by strings of red plastic floating buoys, and the other half filled with exercise equipment and sweating people.  Through my school years, some of my friends came there regularly to practice on the swim team and I thought, how can they endure the smell and the sting of chlorine in their eyes, and the effects of chlorine on their hair?   Swimming was fun but I preferred open water for those reasons.   

If the smell of your home tap water reminds you of a chlorinated pool or bottle of bleach, it may be a high standard use of chlorine, or the effect of free chlorination.  The City of Fort Lauderdale Public Works Department defines free chlorination as “a temporary process that distributes free chlorine in place of combined chlorine (chloramine) throughout the water distribution system as part of routine distribution system maintenance.” It is a standard procedure used by most water utilities across the United States to maintain and protect DWDSs (drinking water distribution systems). The process is often performed once every two years or so.(springwellwater.com)

There are serious side effects from too much chlorination.  These come from the chlorine reacting with the organic compounds found naturally in the water, producing haloacetic acids (HAAs) and trihalomethanes (THMs).  Inhaling the HAAs and THMs during activities like showering can be more toxic because they exist at a low vapor pressure (they easily evaporate from open water) and can concentrate in your body.  According to a 2005 academic article, THMs are more concentrated in the body when absorbed through the skin than drinking tap water that contains the chemicals (springwellwater.com).  Consuming water with HAAs or THMs can lead to several serious health complications, such as stillbirths, bladder and rectal cancer, congenital disabilities, increased risk of kidney and liver cancer. It can also cause problems with the heart, kidneys, liver, and central nervous system.

Besides the serious health effects described above, you’re probably familiar with the consequences of showering and washing your hands with chlorinated water: itchy, dry skin and frizzy, dry hair.  Who knew that “swimmer’s hair” would be the plague of everyone using the municipal water systems?

If I merely read the annual water report from my supplier, I would not have all the information.  Unfortunately (and you can see this in the following excerpt: only certain contaminants are reported), water distributors do not report the full picture.  Here is the water company’s report, that did not include Dichloroacetic acid (DCA):

And here is a reports from a watchdog group in the same year on the same water system.  From EWG.org: 

Results from mytapwater.org are also available in most states (but my locality was not available).  

It usually pays to dig a little deeper, and I didn’t even have to spend any money to do it (although there are plenty of test kits that will help you; see mytapscore.com).   Once you know what contaminants are in your water, you can consider ways to eliminate them.  EWG.org has a contaminant database that tells what risks toxins pose, and how to filter them.  For example, Haloacetic Acids (HAA5) can be filtered by activated carbon filters, or reverse osmosis. 

What else does excess chlorine do?

Unfortunately, chlorine also corrodes copper pipes.  Copper is very durable and highly corrosion-resistant in most underground applications (copper.org), but I would say that in this age of mass disinfection using chlorine, copper is a weak link for building piping systems.  Chlorine is a strong oxidizing agent that reacts readily with materials in the piping system, including copper, other metals and plastics to create oxide and chloride compounds. According to this industry website, “In applying shock chlorination to a copper system, a reduction in the chlorine residual over time will nearly always occur, and does not indicate that the chlorine is being depleted in fighting bacterial contamination. Therefore it is inappropriate and often damaging to the copper system to shock chlorinate the system, measure the chlorine residual and then repeat the shock chlorination and measurement multiple times trying to achieve a specified minimum drop in the chlorine content.”  Unfortunately, though, this is what municipal water systems do, because chlorine is a cheap disinfectant.  According to this 1982 study, “… free chlorine is the agent chiefly responsible for the corrosion of copper in chlorinated domestic water supplies”, but adjustment of the water pH after chlorination to 7 or 8, as well as keeping free chlorine to levels of 2mg/l or less, greatly reduces the rate of corrosion and extends the life of the copper systems.  For homes that were built with copper piping (before the advent of PEX and similar materials), this information is critical to the integrity of your piping!

Chlorine is also detrimental to plants and fish.  If you love growing plants in and around your home, “too much (chlorine) can accumulate in leaf tissue, resulting in leaves with a scorched or burned appearance. The leaves may also appear smaller than usual and may yellow and fall off early.”(springwellwater.com)  Here’s an easy way to get rid of most of the chlorine for watering plants:  run tap water into a large container or pitchers without lids, and let it stand open to the air for a day or so.  Most of the chlorine will dissipate from the water.  Fish may require more extensive filters, as the chlorine can burn their gills.  

According to the CDC, chlorinated water is safe for both humans and dogs to drink in concentrations up to 4 milligrams per liter (rover.com), but that does not take into account the organic byproducts (DCA and HAA5).  At least you could do the same for your pets by letting the chlorine evaporate from open containers before setting it out for them to drink.  At best, you can provide water from the same filters that you use!

If you sense that something is off with your water, you can speak up about it.  Erin Brockovich (the real-life heroine depicted by Julia Roberts in the 2000 movie) is the founder of the Erin Brockovich Foundation, a nonprofit organization created to educate and empower communities in their fight for clean water, and she has released a new book about the plight of America’s water systems and what individuals and groups are doing about it.  Her Facebook post on July 14, 2020 tells a lot:

“If your drinking water smells like bleach... there is a PROBLEM. Do not listen to the water utility providers when they tell you "everything is fine... your drinking water meets all the requirements"... that's just crap.

When you smell chlorine in drinking water it is most often the result of chlorine mixing with total organic carbon (DIRT) the utility fails to clean out of the water like they are supposed to. Water quality changes daily and through out the day... it is impacted by UV rays... and temperature changes. This changes how water is treated... but many utilities fail to do it right and cheat the regulatory system... many feed ammonia to sequester the chlorine and mask the real - toxic - consequences of doing so.

Bottomline... if you smell chlorine THERE IS A PROBLEM... and you need to ask questions.

1.   What is the amount of chlorine/chloramine we have in our distribution system?

2.   Are we experiencing nitrification?

3.   Are we conducting a burn or flush?

4.   What is your total organic carbon reduction percentage?

5.   Is there an algae bloom?

...and scores more... but start here. 

Stop buying their lies. You know when something is wrong! It's time we make it right!”

And on February 23, 2021, here is her response to an article on the water system in Stafford, Virginia:

“I am fed up with the barbaric practice of free chlorine burns applied  by drinking water utilities that loose control of their distribution systems... more so the ridiculous lies they tell!

"The free chlorination process does not adversely affect the water quality"... the BIG LIE

Stafford... you will have 75 days from hell... toxic levels of trihalomethanes, biofilm and sludge exposure.

"The flushing also allows any sediments or minerals that have collected in the water mains to be washed out"... right into your homes, hot water heater tanks, appliances, and drinking water.”

Bottom line: Don’t be afraid to be bold in asking questions and testing your water with regards to chlorine and other chemicals used to disinfect it.

At home, you can also start with filters that can be used in water pitchers, on the tap, under the sink, and for the whole home:

• Get started with a water pitcher that can be stored on the counter or in the refrigerator for cold water:
  • ZeroWater 6 cup pitcher ($21) is a small size that can fill your hot water kettle or coffee maker, which because it also removes Total Dissolved Solids (TDS), is beneficial to the longevity of these types of machines.
  • AmazonBasics 10 cup pitcher ($25) gives you more capacity and filters are compatible with Brita pitchers, however it does not remove TDS.
• AquaBliss Shower Filter ($36) can alleviate the discomfort of chlorine on your skin and hair for 10,000-12,000 gallons, which the company says is good for about 6 months of normal use.
• Frizzlife Under Sink Water Filter, $126, can be installed by anyone in about 15 minutes and the filter cartridges remove fine silt, chlorine, chloramine and lead and heavy metals for about 10,000 gallons of water  

Chlorine is an old disinfectant for water systems, but it is not without dangers when used heavy-handedly, so be wise and avoid it when you can!

“Rust” in your sinks and toilets?  Iron in your water can mean iron bacteria in the water

Wait–is that rust in my toilet?  Why is the toilet looking rusty?  You might initially think that the pipes supplying the water might be rusting, and that could be a problem (however, it’s rare).  But if you know that there are no iron pipes supplying your water (if you live in the country with your own well), then you know that pipe rust is not the source of the problem.  Most likely it has to do with high iron content in the water itself, and a certain bacteria that consumes iron. At least 18 types of bacteria are classified as iron bacteria, long thread-like bacteria that “feed” on iron and secrete slime. Unlike most bacteria, which feed on organic matter, iron bacteria fulfill their energy requirements by oxidizing ferrous iron into ferric iron. (Iron Bacteria in Surface Water). 

Iron bacteria are small living organisms that naturally occur in soil, shallow groundwater, and surface waters. These bacteria combine iron (or manganese) in the soil, and oxygen to form deposits of "rust," bacterial cells, and a slimy material that sticks the bacteria to well pipes, pumps, and plumbing fixtures.  These iron bacteria don’t cause disease, but they can create an environment where other disease-causing microbes can grow (like coliform bacteria).  Iron bacteria can get into the well when the water in the well comes into contact with the soil surrounding it, or lakewater, or any rivers and streams.  (Iron Bacteria in Well Water)

If you haven’t had any work on your water system done, and you’re still suspecting the bacteria are feeding on iron pipes, here are the most common types of pipes (from 7 Types of Plumbing Pipes Used in Homes):

1. Rigid copper pipe (water supply)

2. PEX pipe (water supply)

3. PVC pipe (water supply and drains)

4. ABS pipe (drains and vent lines)

5. Flexi Pipe (water supply)

6. Galvanized steel and cast iron (outdated for water supply and drains)

7. Black pipe (only used on natural gas lines)

So, you can see that out of the 5 water supply line types, only 1 has iron in it (#6) and those are considered outdated.  The cast iron and steel pipes that were used in the 1950s have gradually been replaced by one of the other plastics mentioned above.  (A Brief History of Pipe Materials)  Therefore, if your home was built after the 1960’s, it would be very common for you to have iron in the water supply lines. 

Other than causing brown stains, iron bacteria can also cause the following (Iron Bacteria in Well Water):

• Smells: Swampy, oily or petroleum, cucumber, sewage, rotten vegetation, or musty smells, which may be more noticeable after the water has not been used for a while.

• Colors: Yellow, orange, red, or brown stains and colored water, or a rainbow colored, oil-like sheen.

• Deposits: Sticky rusty, yellow, brown, or grey slime, or “feathery" or filamentous growths (especially in standing water).

These are not the kinds of things you want to see in your sink or toilet!  It can also have detrimental effects on any water softening system, making the water running through it to have an off taste.  To confirm that the problem is iron bacteria, you can get the water tested by a lab.

If you do have iron bacteria, and states like Minnesota have a lot of it, it can be hard to get rid of.  Here are some steps you may consider: 

• If you have a heavy concentration of iron bacteria, the best first step is to have the contractor remove and clean the pumping equipment, and scrub the well casing with brushes.  Make sure that they do not lay any of the equipment on the bare ground, as this could re-contaminate it!  

• Next is chemical treatment, which is also for minor contaminations.  Treatment involves 3 steps: disinfection (or oxidation), retention time, and filtration. (How to Remove Iron Bacteria in Your Water)  Chlorine (bleach), hydrogen peroxide and ozone are frequently used.  Although many companies call all three of these “disinfectants”, the fact is that only chlorine is a disinfectant; hydrogen peroxide and ozone are oxidizers.  Disinfection is the act of killing bacteria, while oxidation causes a molecule, atom or ion to lose an electron (which also kills bacteria as a consequence).

• Chlorine (bleach): Although bleach is cheap and will disinfect, its reactions to organic matter that may be in the water are not good–like haloacetic acids (HAAs) and trihalomethanes (THMs), which are classified as possible human carcinogens.  For more information on these byproducts, check out our article here.  

• Of the two remaining, ozone is a stronger oxidizer than hydrogen peroxide, but hydrogen peroxide systems are less expensive and more readily available from water treatment companies.  According to USWater, extreme amounts of iron and hydrogen sulfide can be removed from the water supply effectively and consistently, it does not need a “contact tank” for retention time, and it does not cause maintenance issues with injection pumps as chlorine does.  (Chlorine or Hydrogen Peroxide – Which is Better for Treating Water?) does not have these byproducts and in addition, has several benefits: it can also rid water of hydrogen sulfide (H2S) smells (rotten eggs), and activated carbon filters used after disinfection last much longer than when used with hydrogen peroxide than with chlorine. (Eliminate Well Water Odors: Four Reasons Why Hydrogen Peroxide Water Treatment Is Best)  According the to Minnesota Rural Water Association, potassium permanganate is also a strong oxidizer that is in common use in Minnesota to remove iron and manganese. (Iron and Manganese)

• Retention time is needed for chlorine to work, therefore the chlorine must sit in the well for a certain period, or if you are using chlorine as a continuous disinfectant, a holding tank is usually set up, with the size being dependent on your household’s normal flow rate (water usage rate).

• Filtration is necessary to remove by-products (in the case of chlorine) and iron products (in all cases).   When chlorine contacts iron in the water, it changes the iron from a ferrous state to a ferric state, making it an insoluble particulate.  This is the state that can be easily filtered.  There are various types of filters available, the most common being activated carbon.  Reverse osmosis and some other types of filtration can remove iron from water without oxidation, and treating your water from the point it enters your home is important for all your appliances, but the iron bacteria may still thrive in your well and cause clogs up to the water treatment point. Iron can clog wells, pumps, sprinklers, dishwashers, and other devices over time. (Iron in Well Water)

If you notice these signs of brown or different colored stains, bad smell or slime deposits in your sinks or toilets, it’s a good idea to get your water tested for iron.  If iron bacteria are present, it’s likely a common problem in your area, and there are local companies who can provide the equipment needed to remove it.  However, it’s best to do your own research on these solutions to make sure that a company doesn’t try to sell you unnecessary equipment (such as a retention tank for a hydrogen peroxide system), and also it’s a good idea to get references and reviews from actual customers.

If you are skeptical about the effects of mold in homes, please stop and read this.

Mold is a fungus that has thousands of species and grows outdoors and indoors, year-round; every building has some level of mold in it. (Molds in the Environment, Johns Hopkins Medicine)  It spreads by microscopic spores which are carried in the air, on clothing, shoes and pets to lodge and potentially multiply indoors. (Basic Facts about Mold and Dampness, CDC) Since the spores are too small to see, many people doubt that mold in the home or workplace can actually cause illness.  Is all mold really bad, or are only some molds bad?  Why do some people become ill while staying a short time in a space while others seem to be unaffected?  What levels of mold should cause concern and what tests are best?   These are very common questions and we would like to highlight some scientific research about mold to understand the answers to these questions.  

Because edible mushrooms and molds growing on basement walls are all classified as fungus, with more adverse reactions arising from handling some than others, there are obviously harmless and harmful species in the family.  It’s overgrowth of the harmful types that can lead to problems in buildings. In the right environment they quickly grow from microscopic spores to visible mycelium (colonies), to sending out more spores into the air and starting other colonies.. 

In general, molds need the following to grow (What You Need to Know About Mold):

• Moisture: even moisture from the air, when it is above 80% humidity, can be enough to sustain mold.
• Warmer temperatures: most molds cannot grow below 40 deg F, which is why refrigerators are kept at 39 deg F and below. 40 -100 deg F sustains mold.
• Organic (carbon-based) materials to digest.  Mold can even grow on glass, metal and other inhospitable environments, if it has dirt or synthetic material to feed on.
• Protection (shade) from UV rays: ultraviolet light kills most mold, so you won’t see it growing in direct sunlight!
• Oxygen: mold needs very little oxygen to survive, so it’s difficult to control mold by depriving it of oxygen.

Therefore, warm, moist areas with natural materials like wood, paper or fabric are great at growing mold, and mold can take root in these areas in as little as 48 hours.  Eliminating the most important material (water) quickly will stop mold in its tracks and not allow it to proliferate.

Molds can emit several types of toxins: mycotoxins and microbial volatile organic compounds (mVOCs). Mycotoxins are solid or liquid.  Of the several hundred mycotoxins identified so far, about a dozen have gained the most attention due to their severe effects on human health and their occurrences in food. (Mycotoxins, WHO). Mycotoxins have also been frequently detected in house-dust over the past decades, and they can be carried through the air on dust, spores or other fragments of mold.  (Detection of Mycotoxins in Highly Matrix-Loaded House-Dust Samples)  By contrast, MVOCs are gaseous, so they are already airborne.  Both mycotoxins and mVOCs can be emitted when the mold colony is disturbed or threatened, by humans, animals or by other microbes.

Ancient plagues and epidemics among animals and humans were likely the result of mycotoxins in foods. Here are some examples: 

• In 1960, about 100,000 young turkeys died in the UK, and scientists discovered that aflatoxins produced by the common molds Aspergillus flavus and A. parasiticus in their feed led to the deaths.  (Mycotoxin: Its Impact on Gut Health and Microbiota)  
• Aflatoxin can also cause liver cancer in humans.  
• Ingestion of ergot, which is a fungal disease of rye and other grains in which black elongated fruiting bodies grow in the ears of the head of grain, can result in ergotism, a painful and often deadly disease.  Ergotism has even been implicated in premeditated poisonings and witch trials, due to its psychoactive effects and disturbances. (Ergot: from witchcraft to biotechnology)
• Sadly, since the isolation of T-2 mycotoxin (a member of the trichothecene mycotoxins, which is emitted from several types of mold including Stachybotrys chartarum), T-2 mycotoxin has been allegedly used as a bioweapon during the military conflicts in Laos (1975-81), Kampuchea (1979-81), and Afghanistan (1979-81) to produce lethal and nonlethal casualties. (CBRNE - T-2 Mycotoxins)  

Illness by ingestion of mycotoxins from a food source occurs more frequently than by inhalation of mycotoxins (for example in dust from mold growing on or behind walls); so with the exception of bioweapons, inhalation of mycotoxins is of a lower concentration so that respiratory irritation is the usual effect.  

MVOCs, being gaseous, are highly inhalable, and their effects can range from annoyance (of the musty smell) to coughing, wheezing, fatigue, headaches, dyspnea, allergies, eczema, as well as serious respiratory issues (Sick Building Syndrome, Mølhave, L. "Encyclopedia of Environmental Health." 663-669.)

So why does mold affect some individuals more than others?  For a long time, individuals who became ill upon entering or spending time in a building were deemed to have more psychological issues than actual physical issues, because testing of the building often revealed no measurable toxins.  There are several reasons for this: 

• First, methods of testing for toxins were not sensitive or specific enough to find the cause.  Dr. Ritchie Shoemaker, a well-known researcher and doctor in the area of mold, Chronic Inflammatory Response Syndrome (CIRS) and Water-Damaged Buildings (WDB), addressed this problem when discussing testing methods in his 2021 paper.  Air sampling methods are not adequate to pick up smaller spores, they may also miss spores outside the air flow boundary and duration of the test, and some spores (like Stachybotrys, commonly called Black Mold even though many other molds are black in appearance) are heavy and don’t become airborne in large numbers, especially if the mold colony is hidden inside a wall. 
• Some bacteria and molds in WDB produce mVOCs, which are toxins not detected by spore air tests.  Only tests that capture mVOCs would be able to detect these. 
• Some people are more sensitive to mold spores, mycotoxins, mVOCs and endotoxins than the general population.  They may be missing genes that allow their bodies to process the toxins, or their immune system may have been chronically overstimulated in a previous chemical or toxin exposure.  These predispositions make them much more sensitive to low levels of toxins from mold and bacteria.

Therefore, mold toxins are sometimes difficult to detect, and they don’t produce similar responses per concentration in everyone due to individual sensitivities. This phenomenon is addressed in a guidance paper to clinicians (doctors and other health practitioners) by the University of Connecticut Health Center.  The paper discusses 5 case studies of patients who were observed to have sick building syndrome due to mold issues in WDB. 

There are several reactions to exposure to mold discussed in the paper:

1. Fungal infections: Infection usually requires direct contact with fungus, and only immuno- compromised or highly sensitive people are at-risk for fungal infections.
2. Allergic and Hypersensitivity reactions: It is well established that fungi can cause allergic reactions in humans, and molds are typically included in the skin test panels used clinically by immunologists to screen for environmental triggers in atopic patients (those who are predisposed to immune responses). Many atopic patients experience allergic symptoms related to molds commonly encountered outdoors. The presence of mold spores in the indoor environment is not in itself a problem when the source is the normal interchange of outside air and the amount and types of spores inside are the same or less than outside. However, mold actively growing on an indoor substrate may affect the quality of the environment by degrading the surrounding materials (weakening the structure) and, more important, by potentially adding unhealthy chemicals and bioaerosols to the indoor air. Higher levels of mold spores inside than outside or the presence of different species inside than outside reflect this “amplification” of mold.  Antigens are toxins that produce antibodies, and in the case of mold, antigens could be spores or spore fragments, mycotoxins, or mVOCs.  “Individuals’ immune responses to these antigenic molecules are determined by their genetic makeup and environmental factors. Important among these factors are the frequency of exposure to the antigens and the intensity of the exposures…Development of sensitization to antigens generally requires repeat exposures, often to high ambient concentrations of the sensitizing material. Once sensitization to an antigen has developed, it requires a much lower concentration upon re-exposure to elicit the reactive phase that we recognize as the clinical manifestation of disease.  In general, the higher the exposure and the degree to which one has been sensitized, the more severe the allergic or immune-mediated response.”  

This is the pathway by which mold “allergies” progress to severe illness, and even death. All five of the cases discussed in the aforementioned paper necessitated the patients to be removed from the buildings (school, office, and home) to recover from their symptoms.  Unfortunately the death of a two-year-old boy in the UK in 2020 was the result of a severe respiratory condition due to prolonged exposure to mold (the family had reported mold in the apartment repeatedly up to three years prior, however, the housing authority did nothing to repair or mitigate it).  This highlights the need for parents to be knowledgeable about the effects of mold as advocates for their children. 

When should a house be tested for mold? We concur with this experienced mold inspector’s methodology:

1. If you have no visible mold but high humidity, it’s probable that mold is starting to grow in the area.  Humidity is easy to feel even without sensors but to be sure, you can get 2 humidity sensors here for only $10.
2. If you find visible mold growth, but don’t know the extent of the damage
3. If you or someone in your family suffers from health symptoms related to mold exposure, then testing of the home would be appropriate.
4. If you smell a musty odor, this is an indication that you have actively growing mold.  These odors are mVOCs.
5. If you’ve already had remediation and need proof that it was performed effectively in order to move back in safely, hopefully a “before” or baseline test was performed for comparison.

What kind of tests are appropriate? 

DIY mold tests are abundant, however, in most cases you get what you pay for.  Petri dishes, while economical, do not provide the quantitative information (how much mold is in the air) and except in the case of sending the dishes in for lab analysis, do not give qualitative information about the types of species. 

If you have only a moderate budget and don’t know where the mold may be coming from, we believe non-viable air sampling can give a lot of information about the spaces in your home.  GotMold? Is an easy way to take these samples in different rooms and get them analyzed by an accredited laboratory. They include an outside sample cassette so that your inside rooms can be referenced against it.  The lowest level of indoor spores should be comparable to an outdoor sample, because mold is in the air everywhere.

If you do have an idea of where the mold is originating, adding a tape-lift, swab or bulk (air filter) sample to your tests can help confirm if a moldy-looking area is indeed mold.  

If, however, an area of your home recently flooded, or you’re experiencing new or worsening health problems, we would recommend requesting a visit from a professional, experienced mold inspector who will not only take samples: they should first of all look at the moisture problems in the home which could generate the mold.  They will also be able to distinguish which type of test is appropriate, and if mold is discovered, whether it’s active mold growth that could be causing illness or inactive mold that’s been dried out and contained behind walls for years.   There is a big difference in renovation scope and cost for active mold and inactive mold!   We understand the health impacts of critically-contaminated spaces on one end of the spectrum, but since many leaks and humidity problems can be corrected in a local, economical way, it’s often not necessary to “gut” a home to remediate it well.  

Beware if the inspector only wants to do ERMI testing.  ERMI stands for Environmental Relative Moldiness Index and was developed by the EPA for research purposes only.  Despite its popularity among many mold inspectors and a number of mail-order labs such as EnviroBiomics and Mycometrics, ERMI has a number of drawbacks that can cause it to miss major mold problems, or overstate minor ones.  

In the end, just as a leak in your outdoor shed can make a stinky, decaying mess, mold can do the same indoors–and it may or may not affect your family’s health, depending on their genetic makeup and previous experiences with mold, chemicals and toxins.   However, we do hope that you will take any water intrusion or humidity problem seriously, because it has the potential to do serious harm.