Tag Archives for " particulates "

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 AirNow.gov 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 AirNow.gov 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

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

Keep Air Quality in Mind When Exercising Outdoors

Keep Air Quality in Mind When Exercising Outdoors

When the weather is nice, many people want to shift their exercise from indoors to outdoors.  There are a lot of benefits to it, such as varied surroundings and surfaces, mood-elevating sunshine, and even a greater incentive to stick with it and go farther, whether you’re walking, running or doing more stationary exercises.  However, should a bad air quality report keep you inside?  The answer is: it depends!  The ability to exercise outside depends on a number of factors such as location, timing, and equipment.  A free and easy way to check air quality and receive updates is from airnow.gov. Using an Air Quality Index (AQI) as a measuring tool ranging from 0-500, your local forecast and larger maps can be color coded to show whether an area is good (green), moderate (yellow), unhealthy for sensitive groups (orange), unhealthy (red), very unhealthy (purple), and hazardous (maroon).  You’ll definitely want to keep AQI between 0-50 if you are more sensitive, but healthy and active athletes can keep going in conditions up to 100 with the right equipment (masks–see below).

First of all, here’s what science says.  Sixteen studies completed between 2000 and 2020 on the short-term health effects from exposure to air pollution during outdoor exercise were chosen for review.  Nine of the 16 papers reviewed demonstrated that exercising outdoors in air pollution results in short-term (temporary) health effects, with lung function impairments being the most observed. The seven other papers, which looked at different health effects, such as inflammation and blood pressure, found no effects.   Besides being nearly evenly split, there was another unexpected result: healthy people who did moderate to high intensity exercise outdoors in low or high levels of air pollution experienced less health effects than when doing low-intensity exercise.  Experts had expected to find the opposite: that low-level exercise afforded less adverse health effects.  This seems to show that deep breathing of semi-polluted air does not seem to negate the good effects of exercise.

While exercising is a good thing, those who are older or are unusually sensitive to air pollution should avoid prolonged and intensive exercise or physical activity when the air quality is moderate or higher.   (Should You Exercise Outside in Air Pollution?)  For everyone else, here are some tips to getting your workouts outdoors with the least air pollution.

Location, location, location

When setting goals to exercise outside, it’s important to have location options and check the air quality in each of them.  If you can find a green area like a large park, chances are that it’s going to have better air quality than a track next to the highway.  Coastal routes near water and marshes also are good filters for air pollution.  This is where an AQI map of your area comes in handy, because you can head to the green areas right away!

Timing, timing, timing

Like the weather, air quality changes constantly in many locations.  That run route you wanted to do during rush hour in the morning might be clearer at noon or 2pm, so don’t lose hope!  When you can be flexible, there’s a greater chance of making your favorite routine work.


If you decide to exercise outside but the air quality is closer to 100 than to 0, consider exercising at a lower intensity or shorter duration.  


City- and valley-dwellers admittedly have a harder time finding clean air for exercising outside.  However, masks have evolved and certain kinds are much more comfortable and adaptable for exercise use.  They must fit properly, however, and make a tight seal in order to do their job.  Here are some masks that have good reviews for exercising:

  • Cambridge Mask Company, $33, make masks that are very well-suited for more polluted areas because they have a 3-layer microfilter for particulates, plus a layer of activated carbon, which not only removes smells but also some VOCs and NOx that are troublesome in high-traffic or smoky areas.  The valved mask styles are recommended for high-intensity exercise.  They are washable and reusable for up to 340 hours, which is around 3-6 months’ average wear.

  • Airweave masks by AUSAIR, $30, are very light and have a copper filter that protects from bacteria, viruses, air pollution down to PM0.1, smog, cigarette smoke, bushfire smoke, and pollen.  The copper filters last 20 days each and come in a 3-pack for $18.

  • FuturePPE Mesh Sports Mask with 5-Layer Carbon Activated Filter, $19, blocks airborne particles, dust, and pollution.  It fits snugly and a 12-pack of replacement filters are on sale at $15. 

  • N95 and P100 masks are also sufficient to filter the particles of air pollution, but they don’t actively remove gasses like VOCs and NOx as a mask with activated carbon in it.

  • Particles can also stick to your clothing, so it’s best to launder them every time you come inside after exercising.

When one or more of these conditions don’t align to let you go outside, remember that without active filtering, air pollution eventually also makes its way inside.  Therefore, use that mask indoors or try to find a gym or studio that uses air purifiers.  You may be in the minority wearing a mask indoors, but your lungs, heart and stamina will shine when you can power through a workout without “choking”.  

Photo by Chander R on Unsplash

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

The Consequences of Flushing the Toilet with the Lid Open

The Consequences of Flushing the Toilet with the Lid Open

Spoiler alert: the consequences are not pretty.  This calming (Australian?) voice and wonderful orchestral soundtrack in this December 2022 video belie the serious and gross subject: how much germs and fecal matter shoot out of a toilet when you flush it.  The University of Colorado Boulder researchers who produced the video found that airborne particles ejected from the toilet traveled at speeds of up to 6.6 feet per second (that’s a very fast walk at 4.5 miles per hour) and reached 4.9 feet above the toilet and smaller particles measuring less than 5 microns hung in the air for more than a minute. 

It’s not a new subject (the subject was first revealed in a 1975 study, and another 2013 study warned about the toilet plume) but the video using UV light brings it to the forefront of our minds and hopefully, engages us in healthier bathroom habits such as closing the lid and sanitizing surfaces more frequently in our own private bathrooms. 

So what should we do?

Ever since Febreeze informed us that odor can be caused by bacteria, bathroom odors are particularly noxious, as we know that the substances that cause it definitely have dangerous bacteria.   There are different ways of removing/preventing bathroom odor (and thus bacteria).  In light of the knowledge of toilet plumes, toilet sprays like PooPourri, although emitting a pleasant odor, seem to be one of the least effective because while spraying on the bowl creates a scented vapor, it does not prevent the emission of bacteria and particulates into the atmosphere.  Other products on the market that have been invented to remove toilet odors at the source, using hardware to pull vapors from the bowl area.  These include:

  • Potty Sniffer Toilet Odor Ventilation System ($271 and up): fan directs air from bowl into a nearby vent.  This is the preferred place to direct these gasses.  However, installation is a bit more complicated as connecting to a vent may require to drill into drywall or cabinets, which needs work to conceal. 
  • JonEvac  Toilet Seat Ventilation System ($300): Replaces your toilet seat with a special seat that has ventilation channels on the underside.  Fan needs to be plugged into a regular wall outlet and activated carbon filter ($80) needs to be replaced every 1-2 years.
  • Splashblocker was invented primarily for hospital settings.  It is a portable “shield” to protect healthcare workers from disease and hazardous drugs (like chemotherapy) that are excreted in patients’ waste, which are aerosolized whenever the toilet is flushed. Previous to this invention, caregivers often placed plastic-backed absorbent pads (such as are used in keeping beds dry from incontinence) over the toilet before flushing, but the cost of these adds up and can easily be sucked down the toilet, creating big plumbing issues.
  • According to this 2020 study, a redesigned toilet seat that can spray a “liquid curtain” of water or sanitizing solution over the bowl when you flush can effectively impede upward movement of particulates, and only 1% of (bacteria/virus-laden) aerosols enter the air above the toilet seat.

The forceful flushing of vacuum-assisted flush toilets, which are commonly used in public restrooms (and all airplanes), actually do a great job of eliminating the toilet plume.  This video uses blacklight just like the study at the beginning of the article, and the difference between regular toilets and this vacuum system seem to be huge.  There were no particles coming out of the vacuum-assisted toilet, but many coming out of the regular flush toilet.  Vacuum-assist toilets still use water to help flush, but nowhere near the amount of regular gravity systems.   This fact comes from the AcornVac website (a manufacturer/supplier of vacuum toilet systems): “a 500 person commercial office building that is serviced by a single vacuum center and 1/2 gallon per flush vacuum toilets will save over 265,000 gallons per year, compared to conventional low flush toilets.”  Water savings aside, I think that the absence of a toilet plume when using a vacuum toilet is their greatest benefit, and it makes me feel a whole lot better about using the bathroom on airplanes!

What happens when the lid is lowered?

Since vacuum-assist toilets and shields are not commonly installed in residences, most people have only a lid to guard against the toilet plume.  What happens when you put the lid down and flush?  Obviously, there are particulates and germs landing on the inside of the lid.  (This is an area that gets skipped over when cleaning, I’m sure!)  The rest of the particulates exit through the spaces between the toilet, seat and lid.  Here are the good and bad results of flushing with the lid down, assessed by researchers at University College Cork:

  • Reduced the number of both visible and smaller droplets during and after flushing by 30-60%
  • increased the diameter and concentration of the bacteria in these droplets.
  • airborne microdroplets were detected for 16 minutes after flushing the toilet with the lid down, 11 minutes longer than when the toilet was flushed with the lid up. 
  • Another study concluded that lowering the lid before flushing “reduced 48% of total number concentration, 76% of total surface area concentration, and 66% of total mass concentration, respectively.”

Using the lid when flushing definitely helps, however some aerosols are still shooting out, and hanging around even longer.  What are the other things we can do to protect from THE PLUME?

  1. If you are in a public place and concerned about transmission of disease, put on an appropriate mask before going into the restroom–at least the aerosols should be filtered out of your air, and germs will not land on your nose or mouth.  As always, wash your hands thoroughly, and don’t touch your mask or face!
  2. If you’re at home, it goes without saying to clean regularly.  
    1. Use a non-toxic disinfectant on all surfaces in the bathroom.  Check out our article on the differences and methods of cleaning, sanitizing and disinfecting. 
    2. Change hand towels frequently, at least twice per week.  For towels and clothing that have been exposed to toilet plume, you can add Borax to your laundry, or pre-soak with it, as it turns into hydrogen peroxide when hot water is added to it.  It’s also generally safe for colored clothes.
    3. Use a HypoAir bipolar ionizer like Germ Defender or Upgraded Air Angel Mobile to sanitize the air and surfaces in your bathroom 24/7!
    4. Leaving your toothbrush in an open place on the bathroom counter sounds icky (for obvious reasons), but stashing it away in a plastic container or drawer is not advised either.  According to a meta-study published in 2012,  toothbrushes stored in aerated conditions had a lower number of bacteria than those stored in plastic and bacterial growth on the toothbrush increased 70% in a moist, covered environment.  What should we do with our toothbrushes?  Sanitize your toothbrush regularly by soaking it in hydrogen peroxide, Listerine, or using an approved UV sanitization device (but not in the microwave). (Is your toothbrush covered in poop? Here's how to thoroughly clean it)
    5. It’s best to switch on your bathroom exhaust fan before every flush, and leave it running for at least 15-20 minutes afterwards.  If your exhaust fan does not seem to remove odor very quickly, then you know it’s not removing the “toilet plume” aerosols.  It may be under-sized, or just old and inefficient.  Because the bathroom exhaust fan is also a very important appliance to remove humidity (and thus prevent mold), check out our article on how to check its size and where it should be vented!

Sorry, I know after seeing that first video, I couldn’t “un-see” it, but I’m grateful that non-toxic cleaners and laundry methods have been invented.  We just need to somehow lower the cost of vacuum-assisted toilets, and bathrooms will get a lot cleaner!  

No-Demo Renos for Air Quality

No-Demo Renos for Air Quality

As of 2024, home renovation is still very popular in the US, but there’s been some interesting developments, such as “no demo reno”.  Eliminating demolition usually means less cost and less time--two very important commodities in renovation!  I’m waiting for designers to take it a step further to challenge themselves to redesign for air quality on a budget, to be judged by air quality experts.  Of course, you can spend thousands of dollars on the latest HVAC and purification systems, but you can also make a big impact with a lot less.  That’s what I’m talking about!

Whether you live in a sealed upper-storey apartment using forced air all the time or only use natural ventilation via windows and doors, furniture placement can affect the airflow and thus the air quality in your home.  According to a 2022 study, furniture layout is a key factor that affects the direction of airflow in a building. Different furniture heights can block or trap natural air or lower the direction of the airflow, thereby producing microscale positive or negative pressure.  It evaluated a naturally-ventilated school in Thailand which was located in a city which was plagued by high PM2.5 every January and May, mostly due to agricultural burning, and wind-blown dust. Under natural ventilation conditions, the direction of PM 2.5 distribution in the classroom was the same as that of the natural air. The air velocity and PM 2.5 concentration in the classroom were correlated positively, whereas the velocity increased, with the increasing concentration of PM 2.5. Adjusting the furniture layout of the classroom, as well as the size of the openings, affected the airflow and distribution of PM 2.5 within the classroom. 

Another study evaluated the pollution level of new furniture (VOCs).  Just by rearranging the furniture in an office with a forced-air system, there was a notable difference between the best and the worst ventilation effectiveness without any changes in the ventilation.  The key learning points were to: 

1) always try to place the pollution source (new furniture) as far away from your usual breathing zone (like sitting at the desk) as possible and, 

2) try to sit in the upflow field of the airflow.

If you aren’t trying to off-gas any new furniture, here are the rules that enable your HVAC to work at its optimum (How Furniture Placement Affects Your HVAC):

  • Make sure the furniture is not blocking any registers or vents.

  • Place furniture away from walls so that adequate airflow behind the furniture can prevent formation of mildew.  This happens when there is not enough air circulation (stagnation) to prevent humidity from saturating surfaces.  For more on how you can avoid mildew with better air circulation/ventilation, check out our article here.

  • Don’t block any windows or doors when placing large pieces such as couches or dressers near them

If you do need to obstruct a vent, try to use a deflector on the register so that air flow is directed to an open area.  They come in a number of shapes and sizes, even adjustable, to match your register/grille and desired direction of airflow.

How to visualize airflow in your space

There are professional engineering programs that can help “see” airflow, but they take quite a bit of measuring and input to get a simulation.  On the simple side, you can use the following to “see” airflow, and adjusting furniture position, window openings, vent positions and fan positions and speeds to modify air currents.

  • A helium balloon that has neutral buoyancy that “hangs” in the air below the ceiling will move with air currents (you can tie or tape a small weight onto it to adjust height).

  • A bowl of warm water with a chunk of dry ice (frozen CO2) will give off fog that moves with air currents (just be careful to use thick gloves when handling!)

  • Old-fashioned soap bubbles (you can make a wand by twisting a paperclip into a loop and use dish detergent and water) blown straight up into the air will tend to move in the direction of other air currents.

  • Candle flames/smoke may also show the direction of air currents.

  • Tape streamers or tissue paper in doorways to see which direction the air flows (tinsel also works).

  • Anemometers are fun devices to play around with, but unfortunately they usually only work very close to a vent or fan; they don’t move with minimal airflows. 

Windows: Don’t forget to pull back curtains or remove them altogether if you are using natural ventilation, because blocking windows with curtains blocks airflow and light!  Curtains are usually necessary for privacy, but you might consider trying sheer or loosely-woven curtains or a decorative fabric screen placed a foot or two inside the window, for more airflow.  If you want to open windows without letting in pollen or air pollution, check out our Nanofiber PureAir Window Screens and Window Ventilation Filters.

Fans: Portable fans can set atop furniture or even be hung on the wall to increase airflow.  Take the time to clean your ceiling fans and make sure they are running in the right direction (clockwise in the heating season and counter-clockwise for the cooling season).  

Even if you’ve lived in a space for a long time and think you have tried “every possible arrangement” of furniture, the act of rearranging furniture every so often is not futile for the following reasons (Rearranging Furniture Could Help You Use Space More Effectively and Give You a Mental Boost):

  • Moving furniture will expose dirt, dust and allergens so that you can clean under it, improving indoor air quality.

  • Moving it may force you to remove or store clutter that also collects dust

  • Moving furniture could expose other air quality problems like hidden leaks or mildew, pet stains or pest infestations

Better furniture arrangement can help you to feel less stuffy and more energetic, even if the airflow changes are minute.  Just a few last tips before you get busy redesigning a room: 

  • remember to use a measuring tape first before trying to move heavy or large furniture to a new spot! 

  • Have your cleaning supplies at the ready to vacuum up dust, cobwebs, pet hair, etc..

  • Call on your friends not only to help with the moving, but also to lend ideas.  

  • If you don't have plants, consider adding a few strategic plants as natural air purifiers (and a pop of color!)

  • Plugging in a small air purifier with a fan like the  Germ Defender or Upgraded Air Angel Mobile will freshen the air and add airflow on a micro scale.

Photo by Nathan Fertig on Unsplash