Category Archives for "Air Quality"

Tight homes need ventilation, but what do I do when it’s smokey outside?

Tight homes need ventilation, but what do I do when it’s smokey outside?

If you’re blessed to be living in a “tight” home (one that doesn’t allow much unintentional air leakage), you should know that mechanical ventilation is really helpful, if not necessary, to achieve healthy indoor air.  Humidity, CO2, particulates and VOCs can build up inside your tight home and without intentional ventilation, can lead to major mold and health problems quickly.  In this case, many people opt for an ERV or HRV so that the energy savings on their tight home don’t go “out the window” (literally!) by exhausting indoor air and pulling in outdoor air without some kind of energy exchange.   For more basic information on building tightness, ERVs and HRVs, check out our article here.

If you have an HRV or ERV and live in an area prone to wildfires, you should prepare for them by having the proper filters in place and knowing what to do with your system.  We’ve helped several clients prepare for this scenario recently, and the “smoke” was not all from wildfires!  Sometimes neighbors with bad or even innocent habits like smoking, barbequing, or sittin’-round-the-campfire can all wreak havoc on your air quality.

First of all, be familiar with your HRV/ERV unit!  This means knowing where it is, how to change its filters, and how to operate the different modes.  Hopefully the installer did a good job of allowing room for maintenance, because just like a furnace/air handler, the filters must be changed or cleaned regularly in order for the unit to work well for many years.  

Many units only come with standard MERV 8 filters, but these are not adequate to handle smoke.  Smoke presents 2 problems: particulate matter (PM10 and PM2.5) and volatile organic compounds (VOCs).  According to the US EPA, a HRV or ERV unit filter must have a Minimum Efficiency Reporting Value (MERV) of 13 to provide effective protection against particulate matter in the air we're going to breathe inside a home or office building if it's smokey outside. (How to keep wildfire smoke out of homes with mechanical ventilation systems?)  Therefore, you’ll need to know what grade filters are in your unit now, and if they are below MERV 13, inquire with the manufacturer on which filters to upgrade to. 

Before you buy new filters, however, you should consider the other part of smoke: VOCs.  You can have a MERV 16 in your unit, but it will not capture VOCs and your home will be filled with the smell of smoke if there is smoke outside!  These insidious gasses are most easily removed with activated carbon.  Therefore, a layered filter (with MERV13 or more plus activated carbon) is really the best defense against smoke.  Since not all units/manufacturers offer carbon in their filters, here are some other options to get rid of the particulates AND VOCs: 

  • Check our offerings to see if we have your filter size in a MERV 13 filter plus carbon.
  • If not, you can cut and layer activated carbon media behind/under your manufacturer’s MERV 13 filter.
  • ((Some units use “panel” filters which are basically squares of bulk filter cut to fit the unit.  In this case you can cut your own using laminated MERV 13 and carbon media. ))

The following options are adapted from HRV with Smoke Filtration:

  • Ensure there is positive pressure inside the house during wildfire events (some ERVs like Panasonic ERV can be balanced to deliver more air than is exhausted from home) so that smoke never wants to come in “illegally”.  
  • Add an inline fan/filter to the intake of the ERV.  This would generate additional positive pressure without overloading the ERV fan and also filter the air before it hits the ERV.  This one has a MERV 13.
  • Get a local HVAC shop to fabricate a filter box that uses a regular furnace filter with MERV 13 (or higher) and carbon, sized sufficiently to overcome any static pressure concerns, and install it in the fresh air intake before the HRV, OR you can add a media filter cabinet to the fresh air intake of your HRV/ERV and leave out the HRV/ERV filter on that side.  We can help with calculations on sizing the cabinet if you have the model of HRV/ERV available (basically it comes down to airflow/CFM). 
  • Lastly, you could add one or more air purifiers or Corsi-Rosenthal cubes (CR cubes) with HEPA/carbon) to your home.  However, this is not ideal because the pollutants have already entered your home and you’re relying on these purifiers to clean your air, instead of having a “guard” filter at the entrance.

Now, here’s the part which requires discernment: in which mode to use the HRV/ERV.  

According to this article on how to keep wildfire smoke out of your home, the intake dampers of HVAC systems should be closed during wildfire incidents, and the equipment should be configured to only recirculate indoor air.  Before any smoke event occurs, you should check that the intake dampers have seals on them and they actually close tightly.  In case you think that you would run out of oxygen in a very short time in this scenario, that just isn’t the case.  Consider this calculation for 1 person staying in a completely sealed space of approximately 600 ft2; they would possibly die of carbon dioxide poisoning (at 12 days!) before low oxygen would be an issue.  Here’s where having carbon in your filters is also good, because it can also filter out some CO2 from inside your home while you close the outside vent and recirculate.  We think that a CO2 meter is a great thing to keep on hand whether or not your home is tightly sealed, and especially if you have any combustion appliances (like gas stoves, water heaters, furnaces, dryers, etc.)  

(I wouldn’t even worry about this “12 days” deadline, either, because very-tightly sealed homes are very rare!  A home in Alaska currently holds the record for being the world’s tightest home, and the owner/builder took the ingenious route of building a “box within a box” in order to air-seal and insulate it well enough for the climate.  At 600 ft2, it has a rating of 0.05 air changes per hour at 50 pascals of pressure (ACH50).  This is less than 10% of the very rigorous Passivhaus standard, which is 0.60 ACH50.)  

So, recirculating air instead of bringing in outside smokey air has a few benefits:

  • It saves your filters and uses them only to filter the small amount of smoke that leaks in through unauthorized leaks (or briefly opening a door). 
  • It maintains the air quality of the room above that which you would have if you were bringing in outside smokey air.
  • Depending on where the intake filter is located, it could save you cleaning your HRV by not passing unfiltered smokey air through it.

This last point may not be obvious, but not all HRV/ERV manufacturers consider that wildfire smoke is a real threat to the operation of their units, because some have intake filters on the exhaust side of the heat exchanger:

Source: “How ERVs Work”

Do you see the “Fresh air from outside” on the lower left?  Imagine that this is “smoky air from outside”, passing through the fan and then through the heat exchanger, before passing through the filter on the upper right.  All those particulates just passed through a heat exchanger, and it’s likely that some of them get stuck there until they are manually cleaned out. Particles sticking to a heat exchanger reduce its efficiency and depending on their chemical makeup, may damage the surface of the heat exchanger.  Now, placing the filter on the lower left poses a maintenance issue, but it shouldn’t negatively affect the operation of the fan or heat exchanger.  This is why having a separate filter on the fresh air intake before the HRV/ERV and leaving off that top right filter inside the unit, may be the best option in wildfire areas. 

One last point: although we’re not huge fans of completely “smart” homes due to the EMF they emit, if you travel a lot or have an HRV/ERV system installed in a vacation home, it is worth practicing operating it remotely (via an app).  In real emergencies, roads can be closed quickly and if you are not able to get home right away, it becomes the difference between being able to come “home” to a clean house and one that smell like smoke (because even carbon filters will not be able to adsorb VOCs for an extended or intense event).  

Any smoke (cigarette, wildfire, campfire, barbeque, industrial or traffic accidents, etc.) is very unhealthy, so we need to do our best to keep it out of our homes, even at the cost of not ventilating for the duration of the smoke event.  The particulate matter in smoke is especially dangerous for children and people with respiratory or cardiac conditions, because fine particulates can pass from the lungs to the bloodstream. The best line of defense against particulate matter is an airtight building envelope, which by extension means closing the intake dampers of ventilation systems.  Filters with a MERV 13 rating or higher, and activated carbon if possible, should be used in HRV or ERV systems and central air conditioning units so that these units can remove any smoke that gets in.  One or more portable air cleaners with a HEPA filter and carbon are also a very good addition for use in common rooms or bedrooms at night.  It all comes down to preparation…having the filters on hand (or better yet, already installed) and knowing how your unit works is worth a lot of clean air when the smoke suddenly appears around your home! 

Photo by Egor Vikhrev on Unsplash

Marijuana smoke, just like cigarette smoke, is an air quality problem that affects a lot of people.

Marijuana smoke, just like cigarette smoke, is an air quality problem that affects a lot of people.

According to Gallup Polls, approximately 17% of Americans smoked marijuana in 2023, which is up from 12% in 2017-2021.  By inference, approximately 83% of Americans don’t directly smoke marijuana, for any number of reasons, but a good number of them deal with it as secondhand smoke (as evidenced by the number of inquiries we receive about how to protect against/remove it).  

A misguided perception: According to Beth Cohen, MD, MA,  a primary care doctor and researcher in California, her research showed that in 2017, 26% of people thought that it was safer to smoke a cannabis joint than a cigarette daily. In 2021, over 44% chose cannabis as the safer option. People were similarly more likely to rate secondhand cannabis smoke as being “completely safe” compared with tobacco smoke, even for vulnerable groups such as children and pregnant women. (Many people think cannabis smoke is harmless − a physician explains how that belief can put people at risk)  

Yet despite these increasing opinions that marijuana smoke is less dangerous than traditional cigarette smoke,  “Smoke is smoke. Both tobacco and marijuana smoke impair blood vessel function similarly. People should avoid both, and governments who are protecting people against secondhand smoke exposure should include marijuana in those rules.”  -Matthew Springer, cardiovascular researcher and Associate Professor of Medicine, University of California, San Francisco

If non-smokers are in the majority, why are they having to fight for the right not to breathe it?  We can think of several reasons:

  • Conflicting studies done over the last decade have perpetuated confusion.  For example:
    • This 2012 study found that occasional and low cumulative marijuana use was not associated with adverse effects on pulmonary function, specifically air flow rate and lung capacity.  
    • In 2022, Researchers from Ottawa Hospital General in Canada compared approximately 150 lung scans from marijuana smokers, tobacco-only smokers and nonsmokers. The study found that rates of emphysema, airway inflammation and enlarged breast tissue were higher in marijuana than in tobacco smokers.  The scans showed that 75% of the marijuana smokers had emphysema. Slightly less than 70% of tobacco-only smokers had emphysema, while only 5% of nonsmokers had it. Emphysema, a form of chronic obstructive lung disease (COPD), is the third leading cause of death in the U.S. (Smoking marijuana may be more harmful to lungs than smoking cigarettes, study finds)
  • Tobacco giants Altria and Reynolds American together with convenience store retailer networks have invested billions into the marijuana industry and actively support legalization.  They produce and market products that support both tobacco and marijuana, like e-cigarettes and vape pens.  (Protecting Nonsmokers from Secondhand Marijuana Smoke)
  • Have societal norms flip-flopped?  Less than 20 years ago, cannabis users were advised to be “discreet”, but with widespread legalization, that’s no longer applicable.  Furthermore, you could say that those who don’t smoke are now being pressured to be discreet!.  Included in the 2008 paper “Civic Norms and Etiquettes Regarding Marijuana Use in Public Settings in New York City” is a resource from the Cannabis Action Network’s 2005 “Good Neighbor Guidelines” promoting both marijuana use and etiquettes: “Have fun with cannabis, but in your neighborhood keep a kind, discrete, polite profile. Do not consume your cannabis openly. The fewer people who know you have cannabis around, the smaller your exposure to rip-offs, overeager youths, cops, and mooches. Keep cannabis plants hidden from public view. Avoid actions that would lead to nuisance complaints like ... overly loud music or too many freaky parties.... Do not keep your stash and paraphernalia in plain view of the doors or windows. Take measures to minimize the distinct odors cannabis has when grown, smoked, or just sitting around.”

Whether it comes down to money or public opinion, we’re finding that people who do not want to inhale second-hand marijuana smoke have to fight for that right, despite some disturbing facts (Secondhand Marijuana Smoke Fact Sheet):

  • Particulate levels from secondhand marijuana smoke are even higher than particulate levels from secondhand tobacco smoke. A study comparing indoor particulate matter 2.5 (PM2.5) levels from secondhand marijuana smoke and secondhand tobacco smoke concluded that “the average PM2.5 emission rate of the pre-rolled marijuana joints was found to be 3.5 times the average emission rate of Marlboro tobacco cigarettes, the most popular US cigarette brand. 
  • Significant amounts of mercury, cadmium, nickel, lead, hydrogen cyanide, and chromium, as well as 3 times the amount of ammonia, are found in mainstream marijuana smoke than is in tobacco smoke.  (A comparison of mainstream and sidestream marijuana and tobacco cigarette smoke produced under two machine smoking conditions)
  • One minute of exposure to marijuana SHS (secondhand smoke) substantially impairs endothelial function in rats for at least 90 minutes, considerably longer than comparable impairment by tobacco SHS. (Endothelial function is the way blood nourishes surrounding tissues via the endothelium, the single-layer cells that line our blood vessels). The findings in rats suggest that SHS can exert similar adverse cardiovascular effects regardless of whether it is from tobacco or marijuana. (One Minute of Marijuana Secondhand Smoke Exposure Substantially Impairs Vascular Endothelial Function)
  • And many more…

So how do people who don’t want these health risks overcome them?

People living in multifamily buildings, whether they are apartments or condos, frequently have problems with this issue, because: the units are commonly leaky, landlords are reluctant to impose sanctions on smoking tenants who are otherwise ideal habitants, and in many states, it’s expensive and risky to bring about legal action. Therefore, it’s the burden of the non-smoker to either “prove” the harm or mitigate the problem on their own.  

In response to our own clients’ problems, we’ve done some research and want to try to help “clear the air”. 

Testing: Since marijuana smoke produces even more particulates than tobacco smoke, tenants with neighbors who smoke or vape marijuana could invest in a particulate monitor like the PurpleAir (or similar) in order to establish a history of particulates. A study used a PurpleAir monitor (PurpleAirTM Model PA-II, PurpleAir.com) alongside expensive lab equipment to show that PurpleAir is just as effective to show secondhand PM2.5 exposure to marijuana aerosol from vaping.  The benefit of using such a monitor is that data is uploaded to the internet every 2 minutes, so that a history can be established.

In addition, if the smoke is particularly heavy or your apartment is particularly leaky, test kits can be used to discover THC residue in your space (THC Surface Residue Detection Test by Mistral, $10, THC Surface Residue/Vape Oil (Pouch) Drug Test, $10)  More expensive laboratory test kits could be used if necessary: EMSL has Marijuana Smoke Contamination Test Kit that costs $95 for lab analysis upon return.  A terpenes test kit from LCS Laboratory is $200-300. The marijuana plant contains a high concentration of terpenes that are responsible for the characteristic smell of marijuana products. Terpenes are natural organic compounds that can be found in most plants, industrial solvents (as turpentine), and many cleaning supplies with the floral or citrus smell.

Cleaning: Due to the chemicals left behind by marijuana smoke, personal protective gear should be used depending on the severity of the residue::gloves, eye protectors, respirators and possibly Tyvek suits are all standard for professional cleaning crews..The best non-toxic cleaners seem to be SmokeOut and THC-Ya:

  • SmokeOut Cannabis RTU Spray by EcoClear is safe for people, pets and wildlife as per the company’s policy.  It neutralizes cannabis odor on contact.  $20/32 oz. from this distributor.
  • THC-Ya! By MoMar is an enzymatic cleaner compatible with hard and soft surfaces.  It encapsulates and neutralizes odors on contact while built-in detergents and beneficial bacteria destroy and remove the source of the odors. 100% biodegradable, no dyes, no solvents, and no phosphates. Non-flammable, non-corrosive, and non-toxic.

According to Restoration and Remediation Magazine, there are several other options for deodorizing and deep-cleaning soft surfaces: hydroxyl generators or ozone machines.  Their preference was hydroxyl generators.  However, both hydroxyl generators and ozone machines have drawbacks.  They may cause more harm than good by generating oxidant byproducts. In a 2021 study, hydroxyl radicals generated by a device reacted with volatile organic compounds present in the indoor space. This led to chemical reactions that quickly formed organic acids and secondary organic aerosols that can cause health problems. Secondary organic aerosols are a major component of PM2.5 (particulate matter with a diameter smaller than 2.5 mm), and exposure to PM2.5 has been associated with cardiopulmonary diseases and millions of deaths per year. (Joo et al.)

Regarding ozone machines, ozone reacts with tetrahydrocannabinol (THC) to produce at least three new oxidant products, from concentrations of ozone as low as found in the natural air.  Therefore, using an ozone generator could increase these byproducts. (Science Daily)  Another study by Berkeley Lab’s Indoor Environment Group found that ozone can remove nicotine and polycyclic aromatic hydrocarbons (PAHs) that had adsorbed onto fabrics after smoking, but that people need to wait a few hours after the generator has run and allow the space to be ventilated of new contaminants generated by the ozone, before going back inside. (thirdhandsmoke.org)

Ventilation: Although ventilation with fresh outside air does dilute contaminants,ventilation does not eliminate all the poisonous toxins and chemical components of secondhand smoke.  The Board of Directors for the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE), the international standard-setting body for indoor air quality, unanimously adopted an important position statement on secondhand tobacco smoke at its summer 2005 conference.  ASHRAE Standard 62.1 reaffirms:

  • There is no safe level of exposure to secondhand smoke.
  • Ventilation and other air filtration technologies cannot eliminate all the health risks caused by secondhand smoke exposure.
  • Tobacco smoke does not belong in indoor areas.

In 2013, the Standard was amended to state:

  • Marijuana smoke should not be allowed indoors.
  • Emissions from electronic smoking devices should not be allowed indoors.

The “ASHRAE Position Document on Environmental Tobacco Smoke” was again approved.  According to this position statement, “ASHRAE holds the position that the only means of avoiding health effects and eliminating indoor ETS exposure is to ban all smoking activity inside and near buildings.”  (Protecting Nonsmokers from Secondhand Marijuana Smoke)

Air purifiers: Our most effective products against these types of contaminants are the Upgraded Air Angel Mobile and Activated Carbon Filter Media; the Air Angel’s AHPCO cell and the media are most potent against VOCs.  Our Germ Defender and Whole Home Polar Ionizer (installed in central AC) work to reduce particulates by causing them to clump together and fall on surfaces, where they can be more easily cleaned.  If you have a central air conditioning unit, you can also use our Whole Home Filters with Activated Carbon to filter and deodorize, setting the fan to “on” so that it’s always filtering.  We also recommend standalone HEPA filters like Medify Air Purifiers (sized for your space).

We get you and have written on how to walk the fine line of dealing with neighbors’ health hazards.  Just like your rights to a habitable home free from mold, tenants should also have a home free from secondhand smoke.  No-smoke.org has similar good suggestions about communicating with smokers and landlords, as well as a new one: getting a note from your doctor!  You can never have too many allies in this fight for clean air, and we want to help as much as possible.

Photo by Ahmed Zayan on Unsplash

How to make your home less susceptible to flooding

How to make your home less susceptible to flooding

Weather forecasts for rain can strike fear in homeowners.  Different parts of the world are experiencing rainfalls that surpass a year’s average within just a few days, or even a few hours.  What can we do to lessen the chance of having to use mops, pumps, demolition and expensive contractors in the aftermath?  

There’s nothing like firsthand experience.  There is an area in Laval, Montreal that historically never flooded, yet in recent years received two “one-hundred year” floods from the Ottawa river.  Andrew Henry is a homeowner who fought very hard to keep his home from flooding for the 2nd time in April/May 2019.  He described his flood prevention/mitigation steps in a series of videos, categorizing them into three main parts:

  1. Keeping the river out of your house:  Sandbags and plastic sheeting are the primary defense for this, adding reinforcements to the back of the sandbag wall where necessary (sadly, they can fail if the water gets too deep).   You may want to keep plastic sheeting and tape on hand at the minimum if authorities in your area supply sandbags.
  2. High water table: Super-saturated soil around your foundation will seep in any cracks in the walls.  
    • In an emergency, you can dig down outside your foundation and set up sump pumps to act as temporary “french drains”.
    • You can also break the floor inside your lowest level at strategic points to install sump-pumps.   This involves a concrete saw and/or jack hammer in most cases, so preparation is key!  If you live in an area prone to flooding, it’s also wise to have spare sump-pumps on hand, along with tubing/piping for expelling the water away from the house, and plenty of extension cords. 
    • Have an emergency power source (small generator) to keep your sump pumps going even if the power fails!
  3. Drains inside the home: you can sand-bag them closed but ideally have sump pumps at the ready or installed in the drains.  For toilets, the best thing you can do is remove the toilet and install a toilet plug (see minute 1:00 in this video).  Andrew did not say it, but chances are that he immediately removed all carpeting/rugs from the ground floor (if he had rugs) in order to clearly see where any water comes in.

There are a lot of great tips in the videos of what he learns as he goes, and his determination pays off, and one month later he can remove the 8 tons of sandbags.  Other seriously flooded homes survived also!  See this house at minute 3:45

City planners and inspectors sometimes have good advice too.  Here is a helpful video from the City of Toronto that suggests the following:

  • If you have any trees running near your sewer line, it may be worth getting a plumber to scope the sewer line to see if tree roots have infiltrated or broken the line, which can cause backups of sewage into your home, even without flooding.  If you don’t have a sewer cleanout, this is also the time to have a licensed plumber to install one.
  • Foundations need to be maintained.  This kind of work includes:
    • Repairing cracks and gaps promptly.  If you have never used it, hydraulic cement is a great product.  You can use it to patch any visible cracks when the walls are dry, and keep the rest of the tub for emergencies, because it even works to seal water out when wet.  It sets extraordinarily fast (3-5 minutes) so you should only mix and use a small amount at a time. 
    • Regrading the soil around your home so it slopes away, not toward the foundation
    • Get a licensed foundation contractor to upgrade your foundation flood protection (see below)
  • Declutter your gutters:  Gutters are important because they direct water off the roof and through the downspout, away from the home.  If they are blocked by leaves and debris, water will pour over them and down the walls of your house.
  • Make sure that downspouts are directed away from the foundation, and discharge at least 2 meters (about 6 feet) from the foundation.

According to the Natural Resources Defense Council (NRDC), some ways to flood-proof your house involve researching flood plain maps before you buy your home (but with storms that break historic precedents, even that doesn’t always work), buying flood insurance, and considering relocating.  Of course, if you really like where you live or can’t move, they also suggest the following:

  • Install a sewage water backstop:  If your basement floor drain backs up after heavy rains, consider getting help from a licensed plumber to install backflow prevention valve(s) and other devices to keep overtaxed sewer mains from backing up into basements.
  • Changing your landscaping includes the following: 
    • Digging depressions known as swales to channel stormwater runoff away from your foundation.  Swales carry water in a non-erosive way.  They can have river rocks or water-loving plants.  
    • Converting concrete or asphalt driveways to gravel or brick
    • Using absorbent mulch can help manage heavy rain and reduce potential flood damage. 
    • Placing a rain barrel beneath a gutter downspout 

Although rain gardens can be used in dry areas to manage water runoff, they can also be used in flood prone areas to lessen the chance that storm drains will become clogged and overflow, leading to flooded properties.  They are depressions made and planted with water loving plants that can absorb large amounts of water and drain it slowly.  If you are able to motivate your neighbors to do the same, the effects are multiplied and can save thousands of gallons of water from pooling or flooding the neighborhood.  Here is a great video showing where and how to make a rain garden.

If grading your lawn and maintaining the gutters and downspouts is not enough to keep your ground floor or basement dry, you may need to have foundation work done.  This can involve setting french drains inside or outside the basement or ground floor, applying a sealant to the exterior of the basement walls, and/or a last resort, waterproofing the interior of the walls.  The reason we mention this as a last resort is because waterproof paint is not a replacement for good drainage–it simply can’t hold back a large amount of water for a long time (check out our article here).  Also, waterproofing should never be installed on both sides of a wall, because it needs to be able to dry out from one side.  Since foundation work is costly and intrusive, it’s best to get plans and quotes from several reputable companies before proceeding.   

Flood conditions can rise very quickly, so there is no substitute for planning and supplies.  Here’s to hoping that you are able to stem the flood/tide and keep your home dry this spring, and all year long!

Photo by jim gade on Unsplash

Termite Architecture: A Lesson in Biomimicry

Termite Architecture:  A Lesson in Biomimicry

Termites in America are largely unseen, building their unwelcome nests inside walls.  Termites in Africa, on the other hand, are quite noticeable: their earthen nests can extend up to 30 feet off the ground!  (I found out that of the 2,600 species of termites, only about two dozen infest and destroy buildings.  Lucky us.)  Other than size, the amazing thing about these structures is that they stay relatively cool inside compared to the outside environment.  How do termites acclimatize their mounds?  The answer is ventilation.  Although some species make mounds that look completely solid from the outside, these actually have micropores, 99% of which are linked together.  The termites use water, soil and their own saliva to create the wall which allows air and gasses to pass through as a sort of living lung or membrane.  Other species’ mounds have “chimneys” which the termites actively open and plug up as the outside temperature changes in order keep the inside at a constant temperature.  This type of architecture is especially beneficial for the Macrotermitinae termite for keeping the nest at 87 degrees F, in order to successfully farm a certain type of fungus for food.

A year ago I wrote the article Can I avoid mold with JUST ventilation? because for those living in hot, humid climates, maintaining a healthy home almost always requires air conditioning.  I walked through the importance of ventilation and how with adequate ventilation, it’s possible to keep humidity levels low enough to avoid mold in many cases.  After finding out that the Eastgate Center in Harare, Zimbabwe is a huge office and retail building that uses no air conditioning, I had to find out how ventilation alone is sufficient in an urban commercial setting!

Zimbabwe is in the southern hemisphere, where summer temperatures and humidity peak in October through February.  Over the course of the year, the temperature typically varies from 47°F to 82°F and is rarely below 42°F or above 89°F.  (weatherspark.com) Humidity is at or above 60% for 7-8 months of the year, and being approximately 4865 ft (1483m) above sea level, Harare is in a “subtropical highland” category.  

Architect Mick Pearce took on the project, and the prohibition of using air conditioning precipitated some extreme design rules:

They said that no direct sunlight must fall on the external walls at all and the north façade [direction of summer sun] window-to-wall area must not exceed 25%. They asked for a balance between artificial and external light to minimise energy consumption and heat gain. They said all windows must be sealed because of noise pollution and unpredictable wind pressures and temperatures, relying on ducted ventilation. Above all, windows must be light filters, controlling glare, noise and security. (1)

Inspired by a television show, David Attenborough’s BBC Life series showcasing the inside of a termite nest in Nigeria, Mr. Pearce designed a building that looks more traditional than modern, but uses 35% less energy than similarly-sized office buildings nearby.  Because of this, the building can afford a decrease of 20% less rent to tenants.  Building costs were reduced by 10% at the outset by eliminating air conditioning equipment.  The following features are a sample that translate into energy savings:

  • Thick protruding concrete “teeth” expand the surface area on walls, so that heating of the walls is minimized during the day, and cooling is maximized at night. 

  • Windows are recessed to avoid exposure to direct sunlight, and ledges around the windows have vegetation to absorb more heat and beautify it.

  • The Eastgate Centre is more like the chimney mounds, as chimneys at the top of the buildings release hot air from inhabitants inside.  A ventilation space below the habitable floors houses low and high-speed fans to exchange warm, CO2-laden air with fresh, cooler air drawn in near the ground and push it up through the building. 

  • The building stays at a constant 82 degrees F during the day (and 57 degrees at night), daytime temps which would be slightly warm to most Americans, but Zimbabweans are comfortable with it.

Source: Biomimicry & Beyond

Mr. Pearce’s description of the design is fascinating!  He went on to design Council House 2 (also known as CH2) in Melbourne Australia using the same passive cooling design, with a slightly more modern façade.  Biomimicry, the emulation of natural forms and processes for the purpose to solve human design challenges, is not about copying nature–who would want to live in a building that looks like a termite mound?  But emulation of the process uses natural ventilation to save energy while providing the comfort, convenience, and productivity demanded by modern society.  

References:

(1) Atkinson, J., 1995. Emulating the termite. The Zimbabwean Review, 1(3), pp.16-19.

Tree Air Filters are Real!

Tree Air Filters are Real!

Did you know that plants and trees filter PM2.5 and PM10 from the air?

If you’re not familiar with particulates and filtration, let me do a short recap: particulate matter (PM) is a big air pollutant in the form of dust, pollen, and most currently, smoke particles.  PM is measured in microns, or a millionth of a meter, and higher levels of PM floating around in the air are dangerous for our lungs, hearts, and whole bodies, because the smallest particles can pass through your lungs directly into your blood.  PM10 is matter that is 10 microns or smaller in diameter, and PM2.5 is matter that is 2.5 microns or smaller in diameter.  The smaller the particulates, the more dangerous it tends to be for us, because in dry conditions small dust can float in the air for a long time and reach down into the deepest parts of our lungs.

The way trees "filter" dust is one reason why air near trees feels cleaner: they intercept particulate matter, which clings to the surface of the leaves, branches and trunk.  The EPA has recognized this and even created a map of certain cities and their suburbs to show how much particulates are removed by trees per year, in kg or %.  EnviroAtlas is a cool interactive tool which you can use to examine 30 cities in the US and their suburbs, to see where the most (or least) particulates are removed by trees. Other layers available are ozone, nitrogen dioxide, carbon monoxide, and sulfur dioxide.  Other tools available in this map include soil drainage and water supply/runoff/etc.  It’s a huge database at your fingertips!

To use this map, go to this link.  It will offer a tutorial, or you can follow these steps to find PM2.5 and PM10 reduction:

  • Click on the box that says “Selected Communities: Combined Communities”.

  • Select a city you’re interested in and the map will zoom to that area.  Then close the box.

  • Click “Pollutant Reduction: Air” in the left-hand column,  and a sub-menu will appear.  Then select either “Particulate Matter: PM10” and/or “Particulate Matter: PM2.5” and check whether you want to see kg/year or %.  Wait for the map to populate with colors.  

  • Once the area has fully populated in color, you can click on an area of the city and the information about that area will appear in another box.  Use the left or right arrows in the box to scroll through it.  In general, darker blue areas absorb more PM than green or beige areas because they have more trees.

  • That’s it!   You can play around with different “layers” of information and check out some of the other tools, where data exists for the whole US, not just selected cities.

Trees are used in this way to create buffers around reservoirs, to keep dust and leaves from blowing in. (Working Trees for Water Quality)  They also can make up hedgerows around fields to prevent weed seeds from blowing in.  (A Guide to Hedgerows: Plantings That Enhance Biodiversity, Sustainability and Functionality)   They are also used as “shelterbelts” to decrease the speed of wind blowing over dry soil to reduce erosion and even prevent snow drifts.  (Why more 'shelterbelts' could prevent dust storms in the future)

Trees are a well-known asset for cities and residential areas because they help reduce air pollution, absorb excess rainwater, reduce erosion and even remediate soil to an extent.  Check out our articles “From the Outside In: How to cultivate a healthy yard that will benefit your indoor air!” and “Surround yourself with trees, and your heart will thank you for it!” to find out how to benefit most from trees in your community, whether you are looking for a place to live or have the opportunity to plant some.  In addition, https://www.itreetools.org/ has free tools with free online office hours that will help you find the right trees for your yard or community space.

Keeping Your Vacation Home Fresh

Keeping Your Vacation Home Fresh

It doesn’t matter whether your “vacation home” is a pull-behind trailer, or a luxurious condo, or a humble cabin in the mountains:  when you “get away” to a relaxing place, you don’t want to spend your precious vacation time trying to figure out how to get musty smells out or remove mold from the linens because the climate inside suffered while you were away.  Here are our tips to make it welcoming and low-maintenance!

First of all, humidity is the most important factor you’ll want to control in order to keep out mold, and you’ll want to keep the humidity under 60% all the time.  If the outside climate humidity rises over 60%, that climate will come inside and settle into soft surfaces, making them a perfect habitat for mold growth. You can only control humidity inside effectively by having a tight envelope, which means sealing up passages where outside air can penetrate in.  If no one will be living there while you’re away, you won’t need fresh-air ventilation, so make your get-away home as tight as possible by sealing windows, doors, attic doors, and other penetrations.  

Also, remember that relative humidity and temperature are closely linked.  For example, if you leave an air conditioner set on 82 degrees and the humidity rises to 80%, you may be at risk of mold forming in less than 2 weeks!  (If you’re wondering how that calculation came to be, check out this fun dew point calculator.)  In addition, relative humidity in a space will increase as temperature is lowered.   Air conditioning will naturally take some of the humidity out of the air, but there are a number of factors that can allow humidity to remain high even when your air conditioner is on. 

Here are some options to keep the humidity under control while you’re not there:

  • If you have wi-fi available in your vacation home, now’s the time to take advantage of technology that can pair with existing units like mini-splits, window or portable air conditioners to enable you to monitor climate and control them remotely.  Cielo is a company that has a number of products that can help you maintain the right humidity and temperature remotely. 

  • Alternatively, if you do not have wifi or app-enabled monitoring, you’ll need to choose a temperature for setting your air conditioner.  Although it’s tempting to set the temperature just under the temperature of melting plastic (haha) to conserve energy, don’t do it!  Setting the thermostat as high as 85 degrees can cause short run times and not allow the air conditioner to remove enough humidity from the air, creating an atmosphere for mold growth.  (No, You Shouldn’t Set Your Thermostat to 85F.  Here’s Why.)  For that reason, it’s ok to set it 7-10 degrees above the temperature you normally keep it while you’re staying there IF you also take into account the outdoor temperature and humidity.  There’s no magic formula for determining this ideal energy-saving-yet-mold-preventing temperature setting, but think about it: if your vacation space is in a hot, humid climate like the southeast US, you’ll want to set the maximum indoor temperature lower than the average outdoor temperature to make the air conditioning come on often enough to remove humidity.  

  • Thirdly, if you don’t have a humidity control setting on your air conditioner, or even an air conditioner at all, it’s best to purchase a dehumidifier with a humidistat and set it to 60% maximum humidity.  This will ensure that humidity is being controlled, no matter what temperature the interior rises to!  Think of this dehumidifier as insurance against mold: if your air conditioner was to stop working, the dehumidifier can still keep your space mold-free if it’s suitably sized for your space.  Check out our article on different types and sizes of dehumidifiers, and be sure to set up a portable dehumidifier with a drain into a lower tub or sink that condensate can safely drain all the time.

  • Leave doors to rooms and closets open for best air circulation.  Just like air purifiers, portable dehumidifiers cannot reach behind closed doors.  

  • Use ceiling fans in rooms and portable fans elsewhere to keep air circulating while you’re away, which will reduce the water content in all your furnishings by evaporation.  ““Evaporation increases the humidity of the atmosphere that immediately surrounds the liquid. This humid air takes some time to dissipate into the rest of the atmosphere. The presence of a breeze, a powerful wind, or some other form of air circulation can speed up this process and make the environment of the liquid less humid. Therefore, by decreasing the humidity of the liquid’s surrounding, a powerful breeze or wind can increase the rate at which the liquid evaporates.” (Factors Affecting the Rate of Evaporation)  This is why disaster restoration companies use powerful fans to move air over wet surfaces, increasing evaporation and removal of water.  With less water in your furnishings, the chance of mold growth is reduced.   You can even add air circulation to any space that has a light socket, such as closets and pantries, by removing the light bulb and screwing in a light socket fan (which come in different designs with exposed or enclosed blades).

  • Make sure your air conditioning and dehumidifier drains are clear and a clean air filter is in place before you leave!  Many homeowners have come on vacation to find their air conditioner or dehumidifier drain pan overflowing and dripping onto ceilings, floors, and other inconvenient places–what a mess that can also turn into hazardous mold!  As a homeowner, make sure to check these drains and change the filter several times during the air conditioning season, or arrange for someone to do the same while you’re away. 

  • Window air conditioners need deep-cleaning sometimes.  If a musty smell is coming from the air conditioner when the fan cycles on, then you’ll know that dust has infiltrated the cooling coils, absorbed moisture, and is nourishing mold growth.  Check our article on how to deep clean it and restore the fresh smell.

  • If you can, shut off water at the main valve to avoid any possible leaks, and switch off the breaker to the hot water heater if it’s electric (turn off gas if it’s gas).  This will avoid water leaks under sinks, which can make a nasty moldy mess!  If you don’t do this, at the very least shut off water to the washing machine, because burst water hoses at the washer are the single largest cause of home flooding.  (Leaving the House for 3 Days or 3 Months? 5 Must-Dos Before Your Trip)

  • Bipolar ionization units like our Germ Defenders, Mobile Air Angels and Whole Home Ionizers are a great way to keep mold away too.  At the very least, plugging a Germ Defender into the bathroom will send out ions to kill mold spores in this small space where air circulation can be a challenge.

  • Leaving a portable HEPA filter with activated carbon running is not a bad idea, either.  Activated carbon will help avoid that “musty” smell.  According to firesafeliving.com,  “plug-in” scent devices are not a fire hazard if you leave them plugged in while you’re away, but we at HypoAir don’t recommend them because a) many plug-ins use toxic chemicals like phthalates and formaldehyde, and b) the freshener will dry out before you return anyway, leaving an appliance running on your wall.  What’s better: make your own reed diffusers with your favorite essential oil (or combination of oils) and place them throughout your space for a safe, no-mess fresh scent!

These extra steps may seem to take more time on those days you’re packing up to leave your vacation home, but when you come back to a home that is ready for relaxing as soon as you open the doors and windows, it will be worth it!

Photo by Lavi Perchik on Unsplash

Summer Cooling: What are our options?

Summer Cooling: What are our options?

Many places in the US and around the world have broken temperature records this June.  Whether you’re in Minnesota or south Texas, it can be tough to keep your home cool during summer while maintaining a decent air quality.  We’ll go over some of the most popular ways of cooling your home and maybe some you haven’t thought of.  

If you’re not familiar with the different types of air conditioners and how they work, check out this article.  Note that newer air conditioners are also often “heat pumps” that can reverse the flow of refrigerant to provide heating in the winter.   

Central Air:  About 66% of homes in the US have central air conditioning, but this is not spread out evenly over the country.  As one would expect, central A/C is more prevalent in the south (37%), west (22%), and midwest (21%), versus the northeast (17%), and newer homes are more likely to have it.  (How Much Value Does Central Air Add to Your Home?) The best thing about central air conditioning is its distribution system, which allows multiple rooms to receive cooling and filtration from one unit.  With any air conditioning, it’s very important to do the following things:

  • Keep your home closed (a sealed system) so that warm, moist air is not introduced.  Letting in humid air from the outside will quickly increase humidity inside, because air at a lower temperature cannot hold as much moisture as warmer air, and humidity climbs.  This applies to windows, doors, and any significant leaks (like the door to an unconditioned attic or crawlspace).   

  • Change the filter on your unit regularly!   We can’t emphasize this enough: a dirty filter not only puts extra stress on the machinery like fans and compressors, but it increases cooling costs, and when the filter gets dirty enough, air will start to leak around the filter and get your evaporator coil dirty, providing food for mold.  Using the highest MERV possible for your unit will help keep the system clean and your air clean as well.  You can check out our article here to find out how to get more filtration out of your current AC system. 

  • For extra filtration, you can cut filter material to fit your vents, just don’t forget to clean or change these regularly, too. 

  • Get your unit serviced regularly.  Here are some things that the HVAC tech will do for you during a service visit:  inspect the inside coils, clean the outside coils and straighten fins if necessary, check the refrigerant levels and add refrigerant if necessary, and test the thermostat.  An HVAC system is a big investment (average $7000), so you’ll want to take care of it!  

  • Make sure your insulation is up-to-par: check air ducts to make sure they are not crimped and are fully insulated, and make sure there are no “bare spots” in the home’s conditioned-space envelope (ceiling or roof).  You’ve got to keep that cool air where it belongs!

Mini-Splits have most of the same parts as a central system, but they don’t have ducts to distribute cool air.  Instead, you could have one outdoor unit combined with up to eight indoor units, with the outdoor unit distributing refrigerant, not air.  In this way, you’ll have eight separate fans and filters inside, but these are smaller.  Mini-splits also have filters, so you’ll want to clean or change these on a regular basis.  One disadvantage with mini-splits is that the air filters tend to be similar to window air conditioners, which are cleanable, but they don’t provide high filtration, just large dust capture.  You will also want to get your units serviced regularly by an HVAC technician.  To get additional dust filtration, try adding standalone HEPA filters in the rooms that seem to get the most dust. 

Window Air Conditioners have come a long way in efficiency and looks!  They are one of the quickest installations, too: from buying one in your local home improvement store to having cool air in your space, could take as little as 1 hour.  Window air conditioners are a sort of “plug and play” cooling solution, but they also require regular maintenance of cleaning the filter.  Because the filter is equivalent to a very low MERV, like mini-splits, you’ll want to add a standalone HEPA filter to reduce pollen and dust.  In addition, if your window unit is more than several years old, it would benefit from a deep cleaning (see our article for tips on how to do that).   Some window air conditioners also have a feature that mini-splits and basic central systems don’t: a fresh air vent.  When this vent is open, you can get a small stream of fresh air from the outside, to dilute stale indoor air.  The only problem is that this air is usually not filtered or conditioned:  it’s the same as “cracking the window” without a screen.  To find this feature and operate it correctly, sometimes you’ll need to refer to the owner’s manual.   New window units with “inverter” type motors can be extremely efficient and this “saddle” style unit by Soleus even gives you your window view back, because it hangs below the window on each side.  It also has a dehumidifier setting to lower the humidity in your space. 

Portable Air Conditioners have become popular because like the name suggests, they are the most portable.  They can cool spaces without a window, as long as you have a place nearby to send the heat through the exhaust duct (through a sliding door with an adapter kit, for example).  You will also need a drain to collect condensate, or you will need to empty the reservoir every so often.  Portable air conditioners have the minimal filters similar to window air conditioners and mini-splits, so they are not able to filter smaller particulates.  It’s really important to clean these filters on a regular basis to keep your air conditioner working well!  Another downside to portable air conditioners is that they are less efficient than window air conditioners, and they have bulky hoses that aren’t the most attractive.  

Fans are the most common cooling systems we have, and many are cheap, at less than $50.  Fans cause evaporative cooling, where the circulated air carries heat away from our bodies in the form of water vapor.  Fans work well to cool us down if there is some humidity in the air.  (See our article about the detrimental effect of fans in extreme dry heat.)  You can use a combination of ceiling fans and portable fans to move air from cooler to warmer areas of your home.  Dreo Air Circulators are very powerful, efficient, and quiet because of the fan design, and because they use brushless DC motors that have a large range of speed with low energy consumption.  Since most fans don’t have filters, you can add standalone HEPA filters to cut down on dust, or add cloth filters to your tower fans. Filters for box fans (20x20”) are mainly the replaceable type, not cleanable, but $45 for a 4-pack of MERV-13 filters could help your space stay a lot less dusty.

Opening the windows is an option if you live outside of polluted urban areas, wildfire smoke, or excessive heat and humidity.  In these cases, it’s best to leave the windows closed and curtains drawn to preserve coolness as long as possible in the day.  If inside temperatures start to equalize with outdoors, however, you can use regular window screens in pristine areas, and Window Ventilation Filters in more polluted areas.  Although the filters restrict airflow slightly, they provide a good buffer against dust and pollen.  Here again, standalone HEPA filters will also help reduce dust in your home. 

Evaporative coolers, also known as Swamp Coolers, began to be popular in the 1920’s and 30’s when electricity was available, but residential air conditioning was not affordable/accessible. (Window air conditioners were invented in 1931 and central air conditioning was offered in 1931 but many Americans could not purchase them due to the Depression).   Swamp coolers use a fan to blow air over a wet membrane, which, if not cleaned regularly, begins to grow algae and smell like a swamp!  This older type of membrane is definitely not something we would recommend for air quality, but newer models like those made by Big Ass Fans uses a proprietary resin coating on the media that resists the growth of algae and mold to keep your airflow clean and people healthy.  Following the cleaning and maintenance guidelines are very important, too.  Another downside of this type of cooling is the massive airflow that could kick up a lot of dust.  However, if you have a large outdoor or unconditioned space and adding humidity into the air is not a problem, then an evaporative cooler could help you stay cool.  It would even help to cool a porch, from which you can open up air to your home to take in cooler air.

Heat Pump Water Heaters can actually cool your space.  It sounds counterintuitive–til you consider what this machine is actually doing.  Instead of creating heat by an electric coil or gas furnace, this type of water heater pulls heat from the surrounding air–in effect making the room in which it’s installed, cooler!  If you have the water heater installed in the garage or another unconditioned space, you can still reap the benefits by using ducts to bring warm air from your house to the heat pump, and cool air from the heat pump back to your house.  Heat pump water heaters do cost more than the basic electric or gas varieties, but according to the Department of Energy, they can be two to three times more efficient than a regular electric water heater.  However, when you consider you’re getting free cooling during the summer, you can deduct this cost from your cooling bill.  Another consideration is the size of room where it is installed.  It must be installed in a room at least 12’x12’, or have ducting to access larger areas, so it can pull the heat it needs from the ambient air.   If it’s time to replace your water heater, check with your plumber to see if a heat pump water heater would work for you!

There are many ways to move cool air from the basement into your home, but consider the quality of basement air before you make this move.  If it’s musty or moldy smelling, you’ll definitely want to get rid of that mold before trying to move that air upstairs.  For this reason, we can’t recommend circulating basement air in the rest of your home.

Whichever way you decide to cool your home, make sure that air quality doesn’t suffer.  Our Germ Defenders, Mobile Air Angels and Whole Home Ionizers sanitize air using bipolar ionization, killing microbes and agglomerating dust and pollen so it’s easy to filter or clean.   Extreme heat tends to lead to increased air pollution, so be conscious of air quality when you open the windows, or even when they are closed and outdoor air seeps in (as it always does except in the tightest of homes).   Check out our article to find out how to ride out a heat/air pollution wave safely!

Photo by Glen Carrie on Unsplash

Should I move out of my home during mold remediation?

Should I move out of my home during mold remediation?

We get this question a lot from homeowners who have discovered mold in their homes and need professional remediation to remove it.  Should I try to stay while the mold is removed and my house is put back together, or find another temporary home?

There are several considerations in making this decision, and they’re not easy.  Sadly, mold remediation is not “elective” or optional once you find it and discover the extent of mold damage.  The traditional option of renovating “room-by-room” is not available here because if it has mold, it has to be remediated as soon as possible if you want to live in your home!  

Why should I move out during remediation?

First off, If you’re not used to putting yourself first, you need to consider the value of your health.  Staying in your home while mold is removed and materials are replaced simply may not be safe for certain individuals.  The following are just some of the conditions that make it safer to leave:

  • Anyone diagnosed with Chronic Inflammatory Response Syndrome (CIRS) or Mast Cell Syndrome (MCS)

  • A compromised respiratory system or respiratory illness like asthma, COPD, emphysema, cystic fibrosis or any number of similar conditions.  Why?  Small particles and mold released into the air can directly affect your lungs and can be extremely dangerous for immuno-compromised individuals.

  • Heart conditions like arrhythmia, congestive heart failure, unstable angina, and any number of similar conditions.  Why?  Small particles and mold released into the air can directly affect your heart when they pass through your lungs into your bloodstream and can be extremely dangerous for immuno-compromised individuals.

  • Mobility handicapped people and the elderly may find it difficult to perform more cleaning and move around areas under construction

  • Work-from-home employees:  construction noise can be distracting and unproductive

  • Families with young children and/or pets  Even with protective barriers between you and the construction, you may find that your living space has increased dust on all surfaces, danger of children and/or pets getting into construction zones,  and construction noise from 7am on any time during the workday.

Secondly, most remediators will say that moving out is the best option to minimize time and labor.  According to Anna Williams, founder of Your Beautiful Home, there are multiple reasons.  If you live at home during the work, the construction crew will have to take extra care to clean up each evening before leaving, as well as pack up their tools.  This takes at least 30 minutes in the evening, plus time in the morning to unpack tools. (Move out during renovation or live through it? That is the question!)  Also, they may not have the easiest access if you are living there, for instance walking and carting tools to the back door to avoid your living space.  So, making it easier and quicker on the remediators means less time and money spent.

And of course, if the remediation requires extensive gutting to your home, it may be just too inconvenient to try to live there.

If you decide to leave, family and friends usually have the cheapest “rates” of any accommodations, but will your relationship survive the remediation?  If your contractor has a reputation for completing projects on-time, staying with family may be a good option.  Alternatives include:

  • Vacation rentals like Airbnb and VRBO

  • Extended stay suites

  • Sublets

  • Corporate housing/short-term rentals (contact a corporate housing agency)

If you move out, you’ll want to make sure to do the following:

  • Store food items in airtight bins

  • Discuss power requirements and when the power will be cut off (will it affect your freezer/any other climatization?

  • Place plastic dust covers on furniture, clothing and carpets if possible

  • Secure any areas of the home that contractors don’t need to access, take or lock up valuables

  • Notify your home insurance and security company

  • Check the “containment” that the contractor has set up.  Be sure to discuss your HVAC system, which can broadcast mold and dust throughout your home if it’s not secured!  If temporary ventilation is needed during extreme heat or cold, the contractor should be able to provide it.  

  • Plan for extra weeks or months in case the remediation schedule doesn’t proceed as planned.

Why should I stay?

Finding alternate accommodations can be stressful if you have to stay with others, or expensive if you have to pay for a rental for your family.  For these reasons, many decide to stay at home.  Homeowners who decide to try to live in their home during remediation should know about the stresses they may endure!  It’s not easy to have workers coming and going through your personal space.  Here are just a few considerations:

  • Increased dust throughout the home

  • Increased noise during workdays

  • Temporary (or prolonged) power and water disruptions

  • Ventilation during extreme temperatures

  • Child safety

  • Parking issues–will there be many vehicles and/or a dumpster parked in front of your house?

  • Access to your kitchen

  • Access to at least one bathroom and shower or tub

  • Access to laundry facilities

  • Sufficient clean space for your family to sleep

  • Sufficient space to work if working from home

  • Delays to the schedule may make the remediation longer than expected

It’s a lot to consider.  Of course, make sure you have as many options available as possible before deciding, including knowing if your insurance will pick up any of the cost for relocation.  If not, you can check with local, state and federal agencies for assistance.  

Staying at home during a mold remediation carries an extra risk: airborne mold.  For this reason, we recommend purchasing extra HEPA filters to place around your living area and portable air sanitizers like the Air Angel and Germ Defender.  Containment of dust and mold spores has to be top-notch–make sure that the contractor follows all safety standards for containment!

Working with the contractor on setting a budget and timeline should be a top priority.  Many contractors may think that delays are acceptable if the homeowner is living in the home or with family–after all, you won’t be paying rent–but make sure that this is not their mindset by including deadlines in the contract, and penalties or cost reductions if they are not met.

By all means, ask for help whenever you can.  Whether it’s taking a weekend getaway break, taking vacation during the remediation, asking for help with children and pets, or having dinner with friends more often, you’ll need to pace yourself so that your health and your relationships aren’t “gutted” either!  

BALOs: voracious good bacteria

BALOs: voracious good bacteria

Bacteria in general have bad connotations: infection and illness to name a few.  But increasing awareness about the benefits of probiotics and natural gut bacteria have taught us that not all bacteria are bad: there are good bacteria too.  Bdellovibrio is in the good bacteria category and recent discoveries about it are spurring more possible uses.

Bdellovibrio bacteriovorus, which was first discovered in 1962, is a gram-negative, aerobic bacteria, which means it has a hard, outer shell that resists the purple stain used to differentiate strains of bacteria.  (For more information on gram negative and gram positive bacteria, check out our post here.)

Bdellovibrio is also a predator.  It is capable of killing and replicating inside over 100 different types of Gram-negative bacteria, including antibiotic-resistant pathogens, giving it a reputation of being a “living antibiotic”.  These prey bacteria include such well-known pathogens as Escherichia coli, Helicobacter pylori, Klebsiella pneumoniae, Pseudomonas, and Salmonella.  This predation behavior has even spawned a new acronym for this type of bacteria: Bdellovibrio and Like Organisms, or BALOs.

According to the following analysis, Bdellovibrio sounds like a voracious alien by attaching to, penetrating, and killing host bacteria, then using them to incubate its own progeny:  “In the wild, B. bacteriovorus uses chemotaxis and a single polar flagellum to hunt groups of prey bacteria. Once in close proximity, B. bacteriovorus collides with individual prey and attaches through an unknown mechanism. Next, B. bacteriovorus invades the prey periplasm (layers around the cell), likely through use of retractable pili, and secretes hydrolytic enzymes that kill the prey within 10 to 20 min of invasion. The predator subsequently remodels host peptidoglycan to form the spherical bdelloplast, where it degrades intracellular contents to fuel its own filamentous growth (liquidates the insides of the prey to fuel replication). Finally, 3 to 4 h following initial contact, the prey cell is lysed (ruptured), and four to six daughter cells emerge from their protected niche (the bdellovibrio babies emerge). Wow!   

Bdellovibrio is found naturally in soil and water, including rivers, lakes, the open ocean, and sewage and wastewater treatment plants (WWTPs).  They are also found in the gills of certain aquatic animals like crabs and oysters, and some mammal intestines.  

Here are some of the proposed uses of BALOs:

  • It could be used in a probiotic to foster healthy human gut microbiota (Higher Prevalence and Abundance of Bdellovibrio bacteriovorus in the Human Gut of Healthy Subjects)

  • It could be an effective treatment for pneumonia in lungs, as both B. bacteriovorus and M. aeruginosavorus could reduce the burden of K. pneumoniae in rat lungs, and B. bacteriovorus treatment is also effective in Yersinia pestis infection of mouse lungs. However, it was found that B. bacteriovorus and M. aeruginosavorus did not reduce pathogenic colonies in the blood, as it did in the lungs of these animals.  (Predatory Bacteria Attenuate Klebsiella pneumoniae Burden in Rat Lungs, Susceptibility of Virulent Yersinia pestis Bacteria to Predator Bacteria in the Lungs of Mice)

  • It could be an effective treatment for Cystic Fibrosis (CF), in which patients have a defective gene that hampers immune response and causes them to be prone to chronic lung infections with an exaggerated inflammatory response.  In CF patients, instead of a diversity of microbiota, only two pathogenic microbes prevail, namely usually the Gram-negative P. aeruginosa and the Gram-positive S. aureus.  Therefore Bdellovibrio was used in a 2014 study to “challenge” these 2 strains in a lab setting, and it was able to reduce the biofilm of both cultures dramatically, even in “flow” settings.  The scientists were even able to photograph (at 30-50 times magnification) Bdellovibrio preying on S. aureus bacteria (see photo below).

Source: Study: Bdellovibrio bacteriovorus directly attacks Pseudomonas aeruginosa and Staphylococcus aureus Cystic fibrosis isolates

  • Prolong food storage:  This study proposes that Bdellovibrio could be used to prolong the shelf life and reduce additives to packaged meat, because it was tested on chicken slices and canned beef and found to reduce colonies of E.Coli by 4.3 log and 2.1 log respectively.  The Bdellovibrio was able to lyse (rupture) all the strains of E. Coli that were tested.  In a separate investigation of Bdellovibrio and E. Coli, this video shows how an actual Bdellovibrio cell multiplies inside an E.Coli cell and destroys it from the inside out.

  • It’s already been recognized as a mode of controlling bacteria in water supply systems.  In 2020 in Varberg, Sweden, a municipal water supply company decided to replace its chlorination system with ultrafiltration, which is an ultrafine mesh filter that prevents microbes from passing through.  Scientists monitored the results closely following discontinuation of chlorine, and some bacteria grew, but then decreased drastically.  By the third month, Bdellovibrio had flourished and harmful bacteria had diminished.  This showed that chlorine had actually suppressed the natural predatory action of bdellovibrio in the biofilm on the inside of drinking water distribution pipes where the good and bad bacteria live. (Predatory bacteria could be used to purify water in the future, study suggests)

So, what’s keeping us from using BALOS as natural antibiotics?  Of course, scientists want to make sure that there will be no harm to humans.  A number of studies using the two BALOs B. bacteriovorus and M. aeruginosavorus “demonstrate their inability to invade mammalian cells, and no apparent pathological effects or signs of cytotoxicity or reduction in cell viability, supporting the proposition that these two BALOs are inherently non-pathogenic to mammals.” (Biotechnological Potential of Bdellovibrio and Like Organisms and Their Secreted Enzymes)  However, scientists are also concerned that prey bacteria could become resistant to it, if it incompletely eradicates the prey. 

In addition, varying amounts of oxygen are necessary for BALOs to work on their prey.  Finally, in complex microbial environments like in our bodies or even in a wastewater treatment plant, it’s not always easy to predict how introduced BALOs will change the biome or which microbes they will prey on, although some do have preferred prey.  Certain chemicals also reduce their effectiveness.

In conclusion, it’s amazing what goes on all around us in microscopic realms.  BALOs could be harnessed in many different ways to improve our health: just the Swedish experiment of removing chlorine showed that it’s not always necessary to use harmful chemicals to kill bad microbes.  Although a lot more research needs to be done, it’s good to know that there are bacteria out there that are on our side! 

Photo by CDC on Unsplash

How a moth’s wings could make your home quieter

How a moth’s wings could make your home quieter

Noise is an important part of our home environment.  The most beautiful, well-designed home, if situated next to a busy, noisy road, falls in value due to its location, location, location.   Apartments in the city may have beautiful balconies that are never used because of the drone of traffic all around.  What if nature offered an innovative sound-absorbing “cloak” for your home?

Bats use echolocation to find their prey.  Smooth surfaces that lack scales or fur make the echoes louder, allowing the bat to close in quickly.  Animals with fur or scales, however, can elude the bat more often.  Scientists have discovered that a certain type of moth have scales that overlap in unique ways to provide exceptional sound-dampening. 

Diamond Light Source is a synchrotron in the UK (a synchrotron is a circular particle accelerator), which was used to examine the nanosized scales on the wings.  According to Professor Christoph Rau, a scientist at this synchrotron, the sound absorbing properties of thoracic moth scales are capable of absorbing about two thirds of the sound energy emitted by their predator, the bat, and significantly increases the insect's survivability.

A separate study by the University of Bristol's School of Biological Sciences showed that the wings absorb as much as 87% of the incoming sound energy. The effect is also broadband and omnidirectional, covering a wide range of frequencies and sound incident angles.

"What is even more impressive is that the wings are doing this whilst being incredibly thin, with the scale layer being only 1/50th of the thickness of the wavelength of the sound that they are absorbing," explained lead author Dr. Thomas Neil.

What could we do with such incredible sound-absorbing performance?  Certain types of noise, like car horns and screeching tires can be detrimental to our health, as we detailed in this article.  Then, there’s also the noise pollution that comes from neighbors or even your own home, which can affect your sleep or concentration while studying or working from home.    Wallpaper or ultra thin sound absorbing panels would vastly improve interiors or exteriors in cities and other loud locations.  Office walls and places where highly sensitive information is discussed could use it.  Even libraries, children’s nurseries and our own bedrooms could use it.  Can you get too much quiet in a space?  I don’t think so, when the world’s noise is only a few steps away!

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