Category Archives for "Air Quality"

A Clean-Air Kitchen Checklist

A Clean-Air Kitchen Checklist

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

Kitchen exhaust vent

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

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

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

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

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

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

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

Refrigerator coils

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

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

The Dishwasher

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

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

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

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

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

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

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

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

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

Photo by Jimmy Dean on Unsplash

The Not-So-Silent Killer: Roads and Highways

The Not-So-Silent Killer: Roads and Highways

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

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

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

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

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

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

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

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

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

  • Bookcases with lots of books

  • Portable closets like armoires

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

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

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

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

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

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

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

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

Photo by Josh Eckstein on Unsplash

Truly Natural Air Purifiers

Truly Natural Air Purifiers

As homeowners realize the extent of air pollution inside the home, they value making or buying air purifiers all the more.  Many purifiers require expensive manufactured filters to be purchased and changed out on a regular basis.  They can certainly do the job but our ears always perk up when something using natural materials comes along!  It’s fun to research how outdoor air is purified by plants and microbes and natural materials.   Here are some of these “new” products that use ancient natural processes.

FIrst, we’ll talk about ones you can actually buy.  

Unless you live with open windows next to a pond with a lot of green stuff on the top, you’d never experience the benefits of using algae as an air purifier.  Or, you could buy an Algae Air Purifier, which cultivates the algae in a low-maintenance tube anywhere in your home.  Algae naturally feed on pollutant particles and gasses like CO2, CO, NO2, VOC`s, PM 10 and 2.5 and transform them into oxygen, turning a problem into a solution. Their ability to absorb and remove the carbon dioxide in the air is 10 times higher than large trees as their whole bodies are photosynthetic. (Can Algae Purify Air?)  AlgenAir looks like a cool modern lava lamp, which has a light, bubbles and soothing white noise.  Algae does have a life cycle of 4-8 weeks, which at the end does not have to be dumped out on the ground.  Since it’s a natural fertilizer, the algae can be poured onto your other houseplants to be used as food.  The Aerium 3.0 comes with the container, one spirulina starter kit and sterile hydrophobic filter.  The subscription plan will reship spirulina every 30, 45 or 60 days for $24.75 for each refill.  

We wrote about the power of moss to purify air previously, but Briiv is a new product that brings it indoors.  It’s a compact filter about the size of a hot water kettle, that looks like a little terrarium on your counter.  How could this green filter possibly last for a whole year?  Yet, it does.  The company claims that it’s as powerful at 3,043 medium-size houseplants, and on its maximum fan setting it delivers 53 cubic feet per minute of purified air. This equates to a CADR of 90 cubic meters per hour.  Reviewers felt more refreshed after sleeping with the Briiv running in their closed bedroom, and enjoyed the fresh outdoor scent.  Since reindeer moss grows at high latitudes and altitudes, it is certainly an uncommon houseplant!  The price of $356 sets you up with one filter which lasts one year, and multiple filters are needed for larger spaces/more rooms.  The replacement filters (moss, coconut and nano matrix) are $38 for one set.  It’s a luxury filter that imparts the scent and look of the outdoors anywhere you place it.

“Biofiltration” could describe the way the algae and moss clean the air, and in a new adaptation,  is also the method of passing air through a thin film containing immobilized bacteria and fungi.  Researchers in Chile focused on reducing volatile organic compounds (VOCs) from building materials and paint, and polycyclic aromatic hydrocarbons (PAHs) from wood-burning.  Current air purifiers typically use activated charcoal to adsorb these pollutants, but the capacity of the charcoal will get “used up” and require disposal at some point. Instead, they found that by using the fungus Fusarium solani and the bacterium Rhodococcus erythropolis, the pollutants could be completely degraded, and the  “filter” did not degrade in performance even after eight months of continuous use. Furthermore, other microbes were captured from the air, demonstrating the potential of the prototype for retaining airborne bacteria and fungi.  (Fresh research for fresh air: Harnessing microbes for removing indoor pollutants)

It is a bit costly to use these “natural” filters in your home; we’re hoping the last one using bacteria and fungi retails for less when it’s finally commercialized!  However, by harnessing the power of 25-3000 houseplants in 1 filter, they are definitely easier than maintaining a forest of indoor plants.  I like the idea of smelling fresh outdoor scents, so I think the Briiv would be my choice.  The compostable filter elements in each device are particularly attractive, and on a replacement-filter basis really are not so expensive after all when compared to many air purifiers which cannot remove VOCs or CO2.  Bravo for the natural versions, we definitely want to see more of these!

Photo by Kent Pilcher on Unsplash

How to reduce annoying Static Electricity (and distinguish it from real electricity)

How to reduce annoying Static Electricity (and distinguish it from real electricity)

Static electricity is just plain rude!  Although it can seem like someone has electrified your doorknob to play a trick on you, most likely your own body is just ridding itself of built-up static electricity.

Why and how does one accumulate that much electricity, anyway?

This topic warrants a small science lesson, so bear with us! As you walk around your house, friction will cause electrons to transfer between surfaces.  Friction on floors (especially carpet), friction between your clothing, and friction between your clothing and body will all cause transfer of electrons, usually resulting in you becoming positively charged (we tend to lose electrons).  Any kind of imbalance in electrons between two objects is basically voltage potential, so the potential continues to build until you touch something that is grounded (a metal appliance, doorknob, or another person) and BAM!  The potential dissipates immediately in the form of a spark or shock.  This means that the missing electrons are suddenly transferred back to you in a moment’s time.  Static electricity shocks are on the average 3000 volts–but very little “amps”, so although they don’t feel good, they usually do not harm you.

You may notice that static shocks in the wintertime occur more frequently or with more power.  What’s up with that?  It’s due to dry winter air.  Warmer air has more capacity to hold water vapor, which when it touches our skin can transfer electrons painlessly so voltage potential never builds up.  However, cold air has less capacity to hold water vapor, so it tends to be dry and more insulating.  That is not good for our sinuses and skin, as well as the nasty static shocks.  

If you’re concerned that it’s not actually static that is causing the shock, there are ways to tell the difference between static and real electricity.  First of all, does the object that shocked you do so every time you touch it?  Static is not constant, meaning that once the shock occurs, it takes some friction to build up the voltage potential again.  Touching the same doorknob a few seconds after a shock usually does not elicit another shock, indicating that it’s static.  Electricity, on the other hand, will cause your hand to “tingle” again every time you touch it (so don’t do this repeatedly until you can find the power source and shut it off!)  The “tingle” is actually the alternating current that powers all the appliances in the house, and it feels different from static.  You can also use a voltmeter to measure the potential between the "ground" of an electrical socket (the little round hole at the bottom of each outlet) and the doorknob. If it's real electricity, you should see about 120 volts (using the 200VAC setting) constantly (although an intermittent ground may flicker up and down). It’s not possible to measure static electricity using an ordinary voltmeter.Here are some weird and dangerous ways that real electricity can make its way to your doorknob or other metal:

  • One person found that the extension cord running under his door (which is a no-no anyway) had gotten a nick in the insulation from the door rubbing on it.  He unplugged it and there were no further shocks.
  • When doors are installed, normally there's at least one longer screw in each hinge in order to get more holding power into the door frame.  There's a chance the screw could have run into a wire, either behind the trim or in the wall (sometimes people hide wires behind trim instead of properly routing them inside the wall)
  • If there's a moisture problem in the wall, any fault in the wiring can be transmitted a longer distance to the doorknob.

Faulty wiring in the wall of a house is a serious safety issue, and even more so faulty wiring or ground problems in an RV or travel trailer.  Because these homes on wheels are insulated by rubber tires, the major way of grounding them is through the ground prong of the electrical cable.  If there is a break in the ground system and hot wires touch the frame, the potential of electrocution is very real.  In a word, if you suspect your RV has faulty wiring or ground problems, disconnect it from power and ask a knowledgeable person or electrician to examine it as soon as possible!

So, getting back to our static problem, how can you reduce the frequency and severity of these shocks?  Here are the easiest ways:

  • Check the humidity in your home and if it’s less than 50%, try adding a humidifier.  Even a kettle of water on an electric hotplate set on low (make sure to check frequently that it has plenty of water and turn it off when you leave the room) can help to alleviate static, as well as sooth your respiratory system and skin.  Adding a cinnamon stick or a few fresh herbs can add a light, pleasant scent, too!
  • Using bipolar ionizers like the Germ Defender, Upgraded Air Angel Mobile or Whole Home Polar Ionizer in your home eliminates static buildup.  Did you know that these use the same type of technology used in electronics cleanrooms to eliminate static charge?  The ions float throughout rooms in your home and help to equalize the charge wherever they touch a solid surface.  
  • Wear more natural fibers (but not silk or wool), as fibers like cotton and linen tend to build up less static charge than synthetic fibers like nylon or polyester.  Silk and wool, while they are natural, do build up static charge because they tend to insulate better than they conduct electricity.
  • Go barefoot when you can.  The practice of grounding or earthing not only avoids static shocks but also provides evidence of other health benefits.  
  • Synthetic hairbrush bristles may generate more friction and static than natural bristles such as boar’s bristles, so you may opt to change your brush.
  • Moisturize your skin and hair with lotions or conditioners to help “conduct” charges into the air.
  • Touch metal surfaces such as doorknobs with another metal first, like a key, so that the charge is not sent directly into your fingers. 

Winter doesn’t have to be so SHOCKING…now that you know where all this extra energy comes from!

Photo by Ilona Panych on Unsplash

How PCM works to keep your home cooler–and warmer

How PCM works to keep your home cooler–and warmer

We are always eager to hear about advances in technology that the average homeowner can use to live healthier lives with less expense or energy.  Lots of new materials are being engineered that use the ambient air or temperature to reduce heating or air conditioning costs.  Phase Change Materials (PCM) are not new, in fact water is one of them!  PCM describes the way that the material absorbs or gives off heat while changing phase (from ice to water or vice-versa) but does not change temperature during the phase change.  Water doesn’t give much advantage in home insulation, however, because the phase change happens at 32 degrees F or 212 degrees F, which are outside of our comfort zone in the home!  However, there are other materials being used that fall in the perfect range for keeping our homes cool or warm.

Phase change material is like a heat battery.  In warmer climates, solar heat starts to warm the roof and wall areas early in the day, but with PCM installed, the heat is absorbed in the material while the material temperature remains constant.  It continues to “melt” inside the pouches as heat is applied, and only increases in temperature after absorbing a lot of heat.  In the evening, PCM gives off the heat back into the attic or wall space, which radiates toward the outside.  In cooler climates, PCM forms a barrier to keep heat from escaping your warm home in the same way.  This is different from traditional insulation such as fiberglass, rockwool or sprayfoam, which all “resist” passage of heat over time, meaning they constantly allow some heat to pass through by conduction, convection, and radiation.  PCM insulation is not meant to replace traditional insulation, but it is a great supplement to it.

There are several companies that manufacture PCM insulation using a soybean/palm oil blends. QE Platinum is a Dallas, Texas-based company, and Phase Change Solutions is based in North Carolina.  The oils are contained in pouched sheets that are flexible.  They can be installed behind drywall (vertically, horizontally or at any angle), above ceiling tiles, or simply laid over existing batt or blown-in insulation in the attic.  The great benefits about this type of insulation are that it is 

  • Non-toxic 

  • Green, sustainable material

  • Moisture, humidity and mold-resistant

  • Self-healing (any punctures cause the material to harden and seal in remaining material

  • Long-lasting (30-year warranty) and guaranteed energy reduction

  • Class A fire rating

  • QE Platinum is also a radiant barrier

  • Has the same thermal mass as a 12” concrete wall!  QE Platinum absorbs and stores up to 100 BTUs per square foot.

  • The company can tailor the melting/solidification range of the PCM to your climate (customized!)

There are two great videos reviewing it.  This reviewer is based in San Diego; he is renovating his older home to get to net zero and is planning to install it in walls and attic.  This reviewer is based in Texas.  Both videos go into the science of PCM and why this product is a game-changer for homeowners and business owners wanting to make their spaces more energy-efficient and comfortable.  We love that it’s non-toxic and easy to install–even for DIYers.  At $2.50-3.50 per square foot, it’s expensive but not ridiculous, and the companies may be able to reduce the cost even more as production increases.  

As great as this material sounds, however, it’s not for every home.  In order for it to be cost-effective, you need to live in an area that has significant daily temperature swings, like 20 to 30 degrees between daily and nightly temperatures.  This allows the PCM to full change phase and be ready for the next day’s cycle.

Another PCM has incredible capacity, but it’s not quite ready for the residential market.  Fraunhofer’s zeolite are small pellets that can be heated, which extracts all their moisture and in the process creates and stores heat.  They can then store that heat for indefinite periods of time.  The amazing things about this zeolite is that due to the huge internal surface area, the pellets store more than 4 times the heat of water (which is has one of the highest heat capacities of any substance), the heat storage is indefinite until water is added, heat losses are very minimal over time, and the zeolite does not change temperature, making it a true PCM.  In the energetic state, zeolites are therefore completely dry; conversely, when water vapor is passed through the pellets, heat is released. The advantage of this is that the energy is not stored in the form of increased heat but in the form of a chemical state. This means that heat is not lost during long-term storage. There is one drawback: Zeolites have poor thermal conductivity, which makes transferring the heat from the heat exchanger to the material and back difficult.  The engineers have finally solved the heat transfer problem by coating the pellets with aluminum.  Amazingly, the aluminum did not impact the ability to adsorb/desorb water, but it enhanced heat transfer. (Thermal Storage for the Energy Transition)  Can you imagine, instead of receiving a heating oil delivery, receiving a delivery of pellets that are already charged with energy, but not hot?  Or using the summer heat in your attic to recharge a bank of pellets for use in the cold winter heating system?  This is incredible technology!

So, homeowners, keep dreaming and scheming to keep energy costs down and comfort levels up.  Science can sometimes satisfy our wish-lists, and when it does, do your research and ask lots of questions to make sure it’s effective and non-toxic.  PCM insulation seems to be a good fit for many smart, green buildings, with no internet connection required.

Photo by Erik Mclean on Unsplash

What to do when you find yourself in an air quality emergency

What to do when you find yourself in an air quality emergency

We’ve all been on the other side of the highway when an accident snarls traffic for miles behind it, and our lanes of traffic slow down but continue to move.  Whew, glad I wasn’t on that side, we think…but sadly sometimes we may find ourselves stuck in an air quality emergency that requires calm, decisive action to quickly get to safe air.  

On Wednesday, November 8, 2023, a fire at a small chemical plant north of Houston sent plumes of black smoke into the air.   According to the Reuters report on November 9, Sound Resource Solutions blends, packages and distributes oilfield and other industrial chemicals including sulfuric acid, acetone and petrochemicals like xylene and toluene, according to the company's website.  These are chemicals that are acutely toxic with the potential to cause serious eye, skin and organ damage, as well as carcinogenic. 

A news article from a Houston news station released the list of chemicals that had been stored on the site during the last 2 years, which confirmed they are quite toxic.  

However, despite the smoke and shelter-in-place orders (which have been lifted), it seems that officials are downplaying the possible effects.

  • According to a Houston news channel video the day after the fire was extinguished (Nov. 9), the Texas Commision on Environmental Quality was monitoring the air and “did not detect any levels of concern from the samples”.  

  • In the same video, an official from the University of Houston said that rain would wash any chemicals out of the air, dilute them out and they eventually go into the ocean.  

Here are the problems we see with these assessments: black smoke was seen moving north toward Livingston, Texas.  Such smoke carries a lot of particulates, which will deposit on businesses and residents’ homes, vehicles and farms (food sources), as well as drinking water facilities.  Also, by our estimates, Shepherd, Texas is 50-60 miles from Trinity Bay, which is open to the Gulf of Mexico.  In order to get to the ocean (Gulf of Mexico), the particulates and chemicals will pass through many drinking water sources!  Once again, it’s probable that authorities are not releasing timely information about hazardous levels of chemicals in the air (and no water reports were discussed).

If you find yourself in an emergency area like Shepherd, Texas, it’s best to do one of two things: stay inside and implement air quality containment measures, or drive out of the area as soon as possible.  Here are our recommendations:

If you choose to stay inside:

  • Close all windows and turn off air conditioning and heating systems if possible.

  • Although most HVAC systems don’t have fresh air intakes, you should close these intakes if they do.  

  • Don’t use exhaust fans like the kitchen or bathroom exhaust fans.  Don’t use clothes dryers, either!  Each of these pull air out of the house, which consequently draws air into the home through cracks in windows and other penetrations.

  • If you have air purifiers, run them continuously.  If you have only one purifier, run it in one small room where you can shelter for most of your time.  If you don’t have an air purifier, here's how to make one using a box fan and a MERV-rated filter.

  • Don’t cook if possible; try eating canned food or food that doesn’t require cooking or heating.  The reason is that cooking and heating food releases even more VOCs into the air, and you shouldn’t vent these with the exhaust fan.

  • Monitor for local air quality updates, because the air quality outside your home will eventually be the air quality in your home.  If air quality outside deteriorates, you may want to gather supplies and necessities and evacuate via car.

  • Use bottled (preferable) or home-filtered water until you are sure that tap water has not been contaminated (which may be weeks or months).

If you evacuate:

  • Make sure that the HVAC in your home is turned off and all windows/doors are closed before you leave.  You can leave air purifiers running in your home, however.

  • Make sure you use the best masks you have until you get out of the area.  Exchange your mask for a new one if you start to have trouble breathing. 

  • Spend as little time outside as possible. 

  • When driving, keep your air conditioner set to “recirculation” mode until you get out of the danger area.

  • Bring/buy bottled water. 

  • Monitor for local air quality updates and check updates by local news authorities. 

  • Upon returning home, clean carefully and thoroughly!  We have recommendations in our article here.

Note that smoke particles, which can contain toxic chemicals, will deposit on the ground, making it easy for people and pets to bring them into the house, so you may want to be vigilant about removing shoes and cleaning pets’ paws when you can.

Many people live or drive within range of being affected by toxic spills, fires and environmental disasters, so your best bet is being prepared (and have a healthy skepticism of all-clear reports until you can research the situation).

Photo by irfan hakim on Unsplash

Air quality in the Operating Room

Air quality in the Operating Room

If you are in the position to have elective surgery, you probably assume that the hospital does its best to mitigate infections by maintaining a sterile environment and using sterile procedures.  The Operating Room (OR) is where patients are at their most vulnerable because hospital-acquired infections (HAIs) can easily happen when the skin barrier is broken, resulting in a Surgical Site Infection (SSI).  Therefore, air quality is very important for patients’ protection, and there are a number of factors that govern the quality of the air.  In the U.S., OR air quality is regulated by three organizations: the American National Standards Institute (ANSI); the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE); and the American Society for Healthcare Engineering (AHSE). Operating rooms require positive pressure, a minimum of 20 air changes per hour (ACH), with a minimum of four outdoor changes per hour. The standard specifies a minimum effective reporting value for air filter efficiency (MERV 16) but does not recommend a type of air delivery system. (Operating Room Sterilization: A Complete Guide to Air Quality)  Here are some details about these requirements:

  • Positive or negative pressure: Traditionally, hospitals make operating rooms positive pressure in order to keep contaminants from the rest of the hospital from infecting the patient on the operating table.  According to ASHRAE 170, operating rooms require positive pressurization of at least +0.01 in.w.g.  However, as operations are sometimes necessary on patients who may have contagious diseases like MERS or SARS CoV-2, hospitals are beginning to rethink whether they want to put the rest of the ward at risk of spreading a microbe from a positive pressure OR room. Discussions are underway regarding alternatives such as a positively pressured OR with negatively pressured ante/setup rooms. Another possibility is to have a negatively pressured OR with positively pressured ante/setup rooms.  (Rethinking air pressure in operating rooms could save lives)

  • The air change rate is a key factor influencing the concentration of microbe-carrying particles (MCPs). The higher exposure risks of surgical incision in the surgical microenvironment may be mitigated with increasing air changes per hour (ACH). (The impact of air change rate on the air quality of surgical microenvironment in an operating room with mixing ventilation)  

  • A key design requirement within ASHRAE 170 for operating rooms is the primary supply diffuser array. The airflow in the primary diffuser array should be unidirectional and downward, with an average velocity of 25 to 35 cfm per sq. ft.  This is recommended with the sole intent of creating a large sterile zone around the patient and medical staff. The standard dictates that the coverage area of the primary supply diffuser array should include the surgical table and extend a minimum of 12 in. beyond the footprint of the surgical table on each side and that no more than 30% of this area may be used for nondiffuser uses (like lighting, surgical gasses, electrical outlets, televisions, etc). This recommendation ensures that enough clean, filtered air is dispensed above the patient while accommodating the complex medical equipment present in today’s modern operating rooms. (How is ASHRAE Standard 170 Applied to Hospital Operating Rooms?)

Although not it’s not mandated, it’s also a good idea to have restricted access to the OR during surgical procedures.  The number of door openings are related to the number of colony-forming units (CFU) in the OR.  According to this study, increased number of door openings and surgery duration increased CFU counts in the OR, but the relationship between these variables was only observed outside the Laminar Air Flow.(LAF). Within LAF conditions, only the number of staff was associated with higher CFU. 

There have been several key developments in systems that promote ultra-clean operating rooms.  Laminar Air Flow (LAF) systems were developed by Sir John Charnley in the 1960s for use during joint replacement implantations.  They are useful for maintaining sterile conditions in the center of the operating room (under the diffusers) because they produce a continuous flow of microorganism-free air, which improves air quality by reducing infectious microbes. However, a 2023 meta-analysis agreed with multiple studies that have found it ineffective for reducing SSIs, and even possibly increasing the likelihood of SSIs, during orthopedic procedures.  (Laminar airflow ventilation systems in orthopaedic operating room do not prevent surgical site infections: a systematic review and meta-analysis)  In addition, air outside of the sterile field (that which is supplied by the LAF system) is often called the “dirty donut” because it is not effectively sterilized by the LAF; air in the dirty donut can be up to 100 times more contaminated than the center.  There are several solutions to improving the air in the dirty donut; Aerobiotix has developed a mobile unit called Illuvia that can reduce the contaminants.  

Source: Cleaning up the Dirty Donut

There is no standard for LAF design in the US.  In addition to the filters employed, different sterilization devices can be employed within or outside the LAF cabinet to increase deactivation of pathogens.  According to Steris, a major design/manufacture/installation firm for OR suites, the following technologies are improving LAF cabinets: 

  • UV light: Use of mobile and ceiling mounted UV light systems is restricted to when patients and staff use full personal protective equipment.  This type of light is also limited to line-of-sight, meaning that disinfection is obstructed by ceiling mounted fixtures and other equipment.  UV light may also embrittle certain materials and fixtures.  Therefore, in-duct UV sterilizers are preferred.

  • In-duct hydroxyl generator systems ultraviolet energy to produce reactive oxygen species known as hydroxyls. Airborne hydroxyls are ideal sanitizing agents which reduce pathogens and neutralize volatile organic compounds (VOC) and a broad range of chemicals. Atmospheric hydroxyls are natural-occurring molecules produced by the action of the sun’s ultraviolet energy on oxygen and water in our atmosphere. The hydroxyls are a natural oxidant and safe for patients and staff to be present during treatment without additional PPE. The system can run continuously and year-round, providing the potential for maximum surgical uptime. An added benefit is that hydroxyls help mitigate odors caused by surgical smoke and cauterized tissues.

According to this 2018 paper, it may be wise to adopt some standards of cleanrooms in ORs.  One such principle is maximizing the use of ceiling space to make the ceiling one large diffuser.  The reason for this is that every gap in airflow delivery (for instance, around a light connection) causes a low pressure area into which airflow is directed, producing turbulence.  Therefore, the operating room would look more like this: 

Source: How is ASHRAE Standard 170 Applied to Hospital Operating Rooms?

LAF is also described as Uni-Directional Air Flow (UDAF), but UDAF may not always be laminar.   Here’s the difference: UDAF describes the direction of flow, however the velocity must be below 90 feet per minute in order to be described as laminar (non-turbulent).  It’s easy to see that the periphery (outside the Ultra Clean Ventilation area in the center) has a lot of turbulent air flow.  Although the large lights over the operating table do produce some turbulence, it is not visualized here.

Source: Air Quality in the Periphery of Operating Rooms during Surgery

Previous LAF systems utilized fans to force air down.  A new type of LAF system called Opragon was developed by the Swedish firm AvidCare, and the system uses Temperature-controlled AirFlow (TcAF).  The technology behind TcAF is based on the ventilation system pumping out slightly cooled air into a zone around the operating table. By taking advantage of the fundamental laws of nature, TcAF breaks the convection currents in an effective and energy-efficient manner. Since cool air is denser than the surrounding warmer air, it drops towards the floor. The air speed is dictated by the temperature difference in the room.  a temperature difference (ΔT value) of -1.5 to -3°C is required between the ultra-clean air and the ambient room air at the operating table to guarantee a fall speed of about 0.25 m/s at the level of the operating table. The technology continually checks to ensure that the ultra-clean air maintains a constant under-temperature of 1.5–3°C regardless of the temperature of the ambient room air. (Temperature-controlled AirFlow)

Air curtain systems like Mediclean emit an air curtain around the perimeter of the sterile area.  The Mediclean system uses Continuous Particle Monitoring (CPM) to measure airborne particles in real-time and uses simple visual alarms. When particles are detected, Mediclean® CPM systems automatically increase the airflow from the UCV to quickly flush the contamination away from the safety-critical area, protecting both patients and surgical staff.

Other innovations include:

  • Surgicube, which is positioned just above the operating table, emits sterile air for minor surgeries.

  • Surgibox, a portable sterile surgical field with self-supporting battery and filter system

  • Air Barrier System, which is a portable diffuser to bathe the surgical site in ultra-clean air 

  • A novel upward-flow design to ventilate using natural stack effect, which is less complex requiring fewer scarce components, lower maintenance commitments, lower energy requirements and operating costs.

And, it’s likely that even more innovations are in the pipeline.  We thought it would be helpful to let you know that even the air in operating rooms is important for the operation’s success and your healing, so you might want to check into it if you need to have surgery!

Specific help for asthma and allergy sufferers

Specific help for asthma and allergy sufferers

In our article “Air Quality in the Operating Room”, we described a new technology to produce laminar air flow called Opragon.  Opragon by Avidicare creates a clean air flow from the ceiling to the floor by creating a 3 degree temperature difference, which causes clean, filtered air to flow downwards, enveloping the entire operating room in clean air.  Now, the sister company AirSonett has produced a device which can drastically improve the lives of asthma and atopic dermatitis sufferers using the same technology.   Airsonett Air4 uses the unique and patented technology Temperature-controlled Laminar Airflow (TLA) to control a flow of lightly cooled, filtered clean air towards the breathing zone. The filtered air sinks with the help of gravity and pushes away the particle- and allergen-rich air from the breathing zone. In this way, at least 99.5% of all particles larger than 0.5 μm are blocked from reaching your breathing zone when you sleep.(Airsonett Air4)

Asthma can often be exacerbated by the allergens in bedclothes and bedding, which are skin dander and dustmites.  Movement in bed and a person’s body heat stir up these allergens, bringing them into their breathing zone.  Many people think that adding an air purifier to the room will help, but in fact air cleaners try to do too much–they attempt to purify the whole room, when all that’s needed is to purify the air in the breathing zone.  According to clinical trials, TLA has proven to be one hundred times more effective compared to air purifiers. (Airsonett Air4)

The machine works by drawing in air from the room under its base through a large HEPA filter.  The air passes through the fan and is then separated into cool and warm air streams.  The warm air stream is discharged through the back of the unit, while the slightly cooler air is moved up through the neck of the machine to the port above the sleeping person, to deliver cool air that drifts down over their breathing zone.  Since the required temperature difference to cause downdraft is small (about 3 degrees F), the unit can employ a Peltier module to cool the air, which is quiet and efficient.  Peltier modules work by passing a DC current through them, causing one side of the unit to heat up, and the other to cool down below room temperature.  Peltier modules are well suited for small cooling or heating loads, and in places where circulating liquids are not desirable (like computers).  The power consumption of the whole unit (fan, cooling and electronics) is 60W. 

Source: Airsonett Air4

This device is pricey (one medical equipment company quotes it at $88 per month for a 5 year lease), but the ease of use, efficacy, and improvement of condition may be worth it for certain individuals.  In these cases, insurance may go a long way to being able to use one in your home. For sure, there are no encumbrances like masks or tubes to deliver clean air, can be operated 24/7, and it can be situated in different areas of the home (over the bed for sleeping, or over a chair or desk for working) because the height is adjustable from 46-55 inches.  Airsonett Air4 is normally prescribed through a pediatrician, allergist, pulmonologist or dermatologist, as it is important that you are diagnosed and receive correct treatment. However, it is also possible to rent or buy Airsonett Air4 directly through the company.

Source: Airsonett Air4

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

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

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

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

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

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

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

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

Photo by Kent Pilcher on Unsplash

Why it’s important to get a proper kitchen exhaust fan and USE IT

Why it’s important to get a proper kitchen exhaust fan and USE IT

Recently (in the last few years) gas stoves have come under fire as a source of air pollution in homes.  While we used to think that the “blue flames” were clean-burning, it turns out that natural gas stoves (the kind of gas used in cities that is piped and metered to homes) can emit a range of pollutants from carbon monoxide, formaldehyde and other harmful pollutants into the air, which can be toxic to people and pets. (Indoor Air Pollution from Cooking)  Thirty-five percent of American homes cook with it, not to mention countless restaurants and commercial kitchens.  The problem is not using gas stoves in the home, however, it is using them with inadequate ventilation.  

Many older homes don’t have a kitchen exhaust vent, or if they do, it is not close enough to the stove or powerful enough to evacuate all the toxic fumes.  Nitrogen dioxide (NO2) is another common pollutant emitted by gas stoves, which the Environmental Protection Agency says is a toxic gas that even in low concentrations can trigger breathing problems for people with asthma or chronic obstructive pulmonary disease.  According to research, including this 1992 study, children who live in a home with a gas stove have about a 20% increased risk of developing respiratory illness.  NO2 concentrations can quickly spike when using as little as the oven and 1 burner without an exhaust fan, to more than double the EPA 1-hour standard of 100 parts per billion (ppb).  (We need to talk about your gas stove, your health and climate change)

Plus, we’re not even counting the burnt food bits that emit VOCs and fine particulates.  Our article about the air pollution cost of cooking–a favorite pastime of many–tells about a test kitchen where the Thanksgiving food items generated particulates levels exceeding that of Delhi, one of the cities with the world’s worst air quality!  You may be thinking about the time(s) a smoke detector may have been set off in your own home.  In my home, cooking during Thanksgiving set off my air quality monitor several times, from cooking bacon in the morning to toasting bread for the stuffing.  And I was using a kitchen exhaust vent, and, the monitor was a good 20 feet away, meaning that levels were even higher at the stove.  Yikes.

It’s just time to cook healthier, and I’m not talking about the type of cooking oil or how much butter you use.  It’s all about the exhaust vent.

If you live in a home with an existing exhaust vent, like a small combination microwave-vent, the first thing to do is check its rated throughput.  Most fans will have a brand and model number somewhere accessible, and the internet is a great resource for looking up this information.  

In our article here, I walk you through calculating how many cubic feet per minute (CFM) of air the hood must move in order to vent properly (it depends on the size of the stove and the size of your kitchen).  Many small vents and microwave combo units are just not powerful enough for the width of stove they are supposed to cover!  That’s exactly why the air quality alarm went off in my home even while the exhaust fan was at the highest setting.

If your vent falls short in the CFM department, or you don’t have a vent, it’s time to upgrade it or supplement. Here are some things to consider if you upgrade:

  • Noise: get the quietest fan you can afford.  Really.  A noisy fan is a big deterrent to actually using it, and the kitchen is a gathering place, so you’ll want to have a fan that makes it easy to enjoy cooking and holding a conversation.  Most of them will operate between 6 and 10 sones, or around 53 to 61 decibels. A normal conversation comes in at around 6 sones, so finding a range hood that operates in that range or below will make it much easier for you to enjoy carrying on conversations in the kitchen. (How loud should a range hood be?)  Another quiet (more installation-oriented) option is to get a model that has a remote fan, which can be installed away from the kitchen in the exhaust line.

  • Direct-Current (DC) Motors: More and more appliances are using DC motors and the advantages are several: they are slim and compact, they are more energy-efficient than their AC counterparts and speed control is easier.  In addition, it may have a longer life and quieter operation.

  • Other features such as LED lighting, optional filtration and pressure--balanced models are available.

  • Make sure to vent outdoors whenever possible.  If you cannot vent outdoors due to where the stove is located or if you’re renting (see below), look for fans with carbon filters that are easy to replace.  Activated carbon removes NO2, as well as VOCs, as long as the fan is powerful enough (see CFM discussion above) and you change the filters on a regular basis.

Here are some good values:

If you don’t have room to exhaust outside above your stove, consider adding a wall fan with outdoor shutter closure:

We also realize that many people rent or live in an apartment where it’s impossible to access the outdoors, or just don’t have any say about installing permanent equipment where they live.  We get that.  Thankfully, there are several portable inventions nowadays that can help get the purifying power you need.

  • CIARRA Portable Range Hood, Desktop Range Hood with 2 Speed Exhaust Fan, $170, would work well for college dorms with a hotplate, micro apartments, or small campers.  It’s not for use with open flame cooking, only electric griddles or hot pots.  It moves about 100 cfm, which is sufficient for this type of cooking, and comes with carbon filter and an optional HEPA filter (although this may clog up quickly if you’re cooking greasy food!)

  • AirHood ($157-$197) is another small portable kitchen exhaust fan, and comes in wired or wireless models. The downside is that this model is 70 dB, which may be loud for some people.  It does not specify CFM but can be used with open flame cooking with adequate distance between the flame and the unit.

  • Air King 9155 Window Fan, 16 inch, White: $147, is a powerful fan that would work well if you have a window in or near your kitchen, preferably close to the stove!  Of course, it could get a bit greasy when drawing cooking fumes, but the fan can be taken apart and cleaned.  It also allows you to close the window behind it during stormy weather without removing the fan.

With so many options out there, there’s hardly any reasons NOT to get proper ventilation for your stove/oven.  The important thing is to USE IT…make your family members or roommates aware of the dangers of NO2 and particulates.  Even toasting bread releases a lot of particulates from the bread as well as all the crumbs left from previous toastings.  So, it’s best to turn your exhaust fan on while cooking anything in the oven, range, toaster or microwave, and leave it on for up to an additional 15 to 30 minutes after you're done to evacuate all those gasses and particulates (and smells).  The plus is that with carbon filters, you don’t have to put up with cooking smells lingering for the rest of the day (well, cleaning the cooking pans is required too).  Here’s to fresh air and easier breathing with the right kitchen exhaust fan!

Photo by Erik Mclean on Unsplash

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