Ways to cope with thick wildfire smoke

Somewhere on this site, someone hooked a furnace filter up to a box fan.  If you use a group of filters ....4...three sides and top...with cardboard on the bottom to form a box with duck tape ....then duck tape it to the draw side of the fan, it should be of benefit.  Of course, the higher quality of filter the better.

So other than planting a wall of trees around your house once the air clears, what you can do now is find ways to increase and improve the oxygen in your home.  

House plants are a good start.  Aspidistra were popular air purifiers in coal-smogged London (which was about the same as being near Portland these last couple of weeks).  Ficus is another popular air filter back in the age of led gasoline.  

Another thing I've been doing in the forest fire smoke season is wearing cotton masks.  Yes, even before 2020, I wore masks around the farm because the smoke can settle in here for months (inversion).  It makes a huge difference.  I go from throwing up from the intensity of the smoke to being able to clean out the chicken house.

But the problem was, I couldn't wear the mask in public without people looking at me strangely.  Thank you 2020 for changing that.  

Several people I know who aren't big into mask-wearing, are wearing their cotton masks to protect against smoke as they have a lot of outside work to do.  

Hey, our place is about 10 miles from the edge of the riverside fire. I bought an indoor air quality meter when our daughter was born, and so I have been able to keep tabs on the air quality. It got so bad one day that my meter went off its scale. It was showing 999 ug/m^3 of PM2.5 (that is bad. Very bad). Thankfully we had an air purifier with a hepa filter, and some replacement filters. The filters I taped over a desk fan, and that worked really well. The furnace filters are not generally HEPA, so they do not catch the very small particles in smoke. If you can find them, (the stores were stripped instantly of all furnace filters around here) then look for the highest MERV rating - anything less than like 11 is basically not removing any smoke. It should be rated to remove pollen and mold spores.

Driving around with the car set to recirculate did improve the air quite a bit - so it dawned on me to swing by the auto parts store. Sure enough, you can pick up an 8" square of HEPA filter for maybe 8 bucks? some of them also have activated carbon, which should help with any of the VOCs in the smoke. I managed to make a passable filter out of computer fans, a cardboard box, a car filter, and the filter out of a shopvac as a pre-filter, and a bunch of duct tape. The air coming out had a reading of like 50 ug/m^3, which is good enough.

The post I am referring to was by Nicole Alderman in "Ways to cope with thick wildfire smoke"

In Australia we have discovered that bushfire smoke has an adverse effect on unborn babies and the placenta.
They are usually born underweight, and the placenta looks like one from a packet a day smoker.

In some cases the placenta needs to removed by surgery!

John F Dean wrote:The post I am referring to was by Nicole Alderman in "Ways to cope with thick wildfire smoke"

The air filter actually works really well. Some people use only one filter, like this:



But, one filter makes the fan sad, and doesn't filter as much air. Two years ago, we made one with two filters:



This year we made it with three filters:



It helps if you can get filters that have one side that's the same size as your box fan's height. The ones we have are 20x20x1, and they work great. Get the highest rated filters you can, as the higher ones will filter more smoke out (but will be more expensive, and might be out of stock because other people might be buying them for the same reason). Any filter is better than none, though. Ours were white when we installed them over a week ago, and now the filters are grey. I've also taken to hanging my wet shirts or towels over the filters to dry. This seems to filter even more, without really taxing the fan too much. Our air quality has stayed great inside, even when it was at 225 outside. We also only entered and exited from the garage, using the garage as a kind of air lock. And, of course, we don't open the windows. And we've refrained from using the dryer or hood/bathroom vents. All of those send air outside, which means the house has to suck (polluted) air in from outside.

Of course, since we weren't exchanging inside air for the cooler outside air, our house has stayed pretty uncomfortable at 76-80 degrees, and I've had to run the portable AC unit (which sends hot air outside, and therefore sucks polluted air in) just too cool ourselves down. But, the box fan filter does a nice job of cleaning the air pretty quickly.

Hi Nicole,

I really dont see why a filter cannot be put on top as well.

I thought the same thing after we'd built it. But, we only had three filters here at home, and I didn't really want to halt construction to go buy another filter. I'll buy four for the next time. I'd like to think there will be no "next time," as we never once had wild fire smoke in the previous 30+ years of my life, or of my parents' and grandparents' life in this area. But, this is the third time in 5 years, so, I think I just always need to have air filters around.

Nicole Alderman wrote:

John F Dean wrote:The post I am referring to was by Nicole Alderman in "Ways to cope with thick wildfire smoke"

The air filter actually works really well. Some people use only one filter, like this:



But, one filter makes the fan sad, and doesn't filter as much air. Two years ago, we made one with two filters:



This year we made it with three filters:



It helps if you can get filters that have one side that's the same size as your box fan's height. The ones we have are 20x20x1, and they work great. Get the highest rated filters you can, as the higher ones will filter more smoke out (but will be more expensive, and might be out of stock because other people might be buying them for the same reason). Any filter is better than none, though. Ours were white when we installed them over a week ago, and now the filters are grey. I've also taken to hanging my wet shirts or towels over the filters to dry. This seems to filter even more, without really taxing the fan too much. Our air quality has stayed great inside, even when it was at 225 outside. We also only entered and exited from the garage, using the garage as a kind of air lock. And, of course, we don't open the windows. And we've refrained from using the dryer or hood/bathroom vents. All of those send air outside, which means the house has to suck (polluted) air in from outside.

Of course, since we weren't exchanging inside air for the cooler outside air, our house has stayed pretty uncomfortable at 76-80 degrees, and I've had to run the portable AC unit (which sends hot air outside, and therefore sucks polluted air in) just too cool ourselves down. But, the box fan filter does a nice job of cleaning the air pretty quickly.

I meant to head back to the other thread to mention what a great idea this is...

I have a manufactured filter; I will definitely build one like this to pair it with. My purpose built one has a sensor, and this is convenient. It uses a blower instead of a fan; generally better when static pressure is called for. It may also have a finer filter, not sure the specs on available filters as above.

But. Big advantages to Nicole's version; cost, and filter surface area. And, those may well be the most important two attributes for most people and most applications... That is a lot of filtration area!

I think one like this will pair very well with my current one; I will probably use a blower instead of a box fan. I have one sitting around... if I get lucky, I will find a smaller DC blower to use. This would let me run this filter without turning on the inverters.. which would be nice, because this smoke has been brutal on my solar system.

I am off grid and rely on solar for everything... and the worst smoke has cut my power to effectively zero. Not helpful!

I am really looking forward to building a permanent house that is heavily earth-sheltered. A nice cool basement with filtration would be heavenly... I usually run three 180mm DC exhaust fans all day when it is hot, and my tinyhouse stays at about ambient temp.. lately I can choose between cooking to death and choking. No power to run the fans nonstop, even if I wanted to bring in unfiltered air. As it is, I run the filter for a few minutes when I come inside for meals, and blast it for a half hour before sleep... and have been one bad day away from running out of power for even this, most of the time.

r ranson wrote:Another thing I've been doing in the forest fire smoke season is wearing cotton masks.  Yes, even before 2020, I wore masks around the farm because the smoke can settle in here for months (inversion).  It makes a huge difference.  I go from throwing up from the intensity of the smoke to being able to clean out the chicken house.

But the problem was, I couldn't wear the mask in public without people looking at me strangely.  Thank you 2020 for changing that.  

Several people I know who aren't big into mask-wearing, are wearing their cotton masks to protect against smoke as they have a lot of outside work to do.  

I find my cotton mask works even better for battling smoke when I get it damp before hand. That seems to catch more particles. I rinse it after each use outside and then hang it up until I need it again.

D Nikolls wrote:
But. Big advantages to Nicole's version; cost, and filter surface area. And, those may well be the most important two attributes for most people and most applications... That is a lot of filtration area!

I think one like this will pair very well with my current one; I will probably use a blower instead of a box fan. I have one sitting around... if I get lucky, I will find a smaller DC blower to use. This would let me run this filter without turning on the inverters.. which would be nice, because this smoke has been brutal on my solar system.

I am off grid and rely on solar for everything... and the worst smoke has cut my power to effectively zero. Not helpful!

I am really looking forward to building a permanent house that is heavily earth-sheltered. A nice cool basement with filtration would be heavenly... I usually run three 180mm DC exhaust fans all day when it is hot, and my tinyhouse stays at about ambient temp.. lately I can choose between cooking to death and choking. No power to run the fans nonstop, even if I wanted to bring in unfiltered air. As it is, I run the filter for a few minutes when I come inside for meals, and blast it for a half hour before sleep... and have been one bad day away from running out of power for even this, most of the time.

I just went and plugged in my watt meter-thing.

Running on high, it uses 105 watts
Running on medium, it uses 92 watts
running on low, it uses 72 watts.

It blows a lot of air, even with a wet shirt hanging over each filter. I wonder how much power a normal air filter uses?

And this is AC power. I just went and looked up a DC fan (I didn't even know about them). I found this tidbit of information amazing:

DC fans are widely regarded as the most efficient type of fans. They consume significantly less power than AC fans. In fact, DC fans consume up to 70 percent less energy to produce the same output as traditional AC fan types. This means, that a 25-watt DC-driven yields the same results as 100-watt AC fan

I'd definitely hook up some filters to your DC fans-- you'll get clean air and a good breeze!

Nicole Alderman wrote:And this is AC power. I just went and looked up a DC fan (I didn't even know about them). I found this tidbit of information amazing:

DC fans are widely regarded as the most efficient type of fans. They consume significantly less power than AC fans. In fact, DC fans consume up to 70 percent less energy to produce the same output as traditional AC fan types. This means, that a 25-watt DC-driven yields the same results as 100-watt AC fan

I'd definitely hook up some filters to your DC fans-- you'll get clean air and a good breeze!

Those ones are plumbed into the wall as exhausts, but I have a couple more somewhere.. a DC squirrelcage blower would be ideal.

The big win will be lack of the ~100W+ draw from the twinned inverters, which cannot be run separately without annoying reconfiguration... and I need them twinned to produce 240V for the irrigation pump for at least a few minutes per day.

My filter is a Coway AP-1512HH; judging by DC draw on the batteries with the unit at various settings, it uses about 40W on max, with ionization off. The medium and low speeds draw so little power it is pretty well lost in the fluctuations of other draws; maybe 15W?

Interestingly, according to the label it uses a DC blower, running at 161V; the efficiency advantage of a DC blower is more than enough to justify converting the AC input to DC.


I looked into the filters a bit more..  the short version: 'While a MERV 16 filter(the highest/best MERV rating) captures >95% of particles in the entire size range tested (0.3-10.0 microns), a HEPA filter captures 99.97% of particles with a size of 0.3 microns.'

So, it is hard to quantify the difference, because the MERV rating is vague... it may be catching 95% evenly across the board, and a couple more passes would improve that.. or it may be doing great with big stuff, and the small stuff is often getting by. Smoke is apparently pretty small, 0.4 micron and up... so.


I wonder if you could increase filter effectiveness by wetting or oiling them, as is done with some truck air filters... Is the wet t-shirt for filtration purposes, or cooling, or?


I am now thinking of looking for HEPA filters to hack up a secondary filter; catching a lot more gunk in one pass is more important with a limited power budget!

So far the Coway unit has been good; I bought it after the 2017 fire season, and this is the first year I have needed it... but it was over 300 bucks then, and I doubt I could find one right now. Feeling pretty pleased with my past self on this one.

D Nikolls wrote:I wonder if you could increase filter effectiveness by wetting or oiling them, as is done with some truck air filters... Is the wet t-shirt for filtration purposes, or cooling, or?

I'm stacking functions!

(1) I had no idea how to dry my clothes without using (A) the dryer and thereby sucking ucky air in, or (B) hanging the clothes out in the smoke-filled air. So I resigned myself to hanging them inside. I didn't want to tax my clothesline with the weight of towels, and really had not enough room to hang up all my laundry as it is, so I draped them on the filter. This seemed to work well for cleaning the air, and didn't stress the fan, so I've been hanging my wet t-shirts on it, too.

(2) Extra filtration! I noticed my cloth mask seemed to catch a lot more smoke when wet than when not-wet, so hanging damp cloth on the filters would hopefully add extra filtration. My husband also wanted to mist the filters to have them catch more smoke, but I wasn't sure if they will deteriorate when wet, and I didn't want to find out the not-fun way. I figure the wet t-shirt does the same thing, without risking the filter.

(3) Yes for the cooling...though our house is humid (usually around 60), so it didn't really do much for cooling unless you were right in front of it. I'm sure this would work a whole lot better in a less damp region.

Basically, I started doing the shirt-draping for all of those reasons. It does seem to help!

This reminds me of Olafur Eggertsson's farm in Iceland, which is at the foot of Eyjafjallajökull volcano. When it erupted in April 2010, he locked up his 160 cattle, including 60 dairy cows in a barn and covered the windows with hay and straw to block the ashes. The cattle survived, because the gases from volcano weren't toxic and the mudslide that followed missed his farm. Article that mentions the farm: A cruise to Iceland on the 10th anniversary of its most famous volcanic eruption.
I took the attached photo three years ago, when I visited Iceland.

John F Dean wrote:Somewhere on this site, someone hooked a furnace filter up to a box fan.  If you use a group of filters ....4...three sides and top...with cardboard on the bottom to form a box with duck tape ....then duck tape it to the draw side of the fan, it should be of benefit.  Of course, the higher quality of filter the better.

I have done this in the past to help with dust and pet hair; just be aware it shortens the fan motor's lifespan.  Be sure you monitor the filters and change them when necessary!

I gave in and got an air purifier by Honeywell from Amazon for under $250, good for around 467 square feet. It’s got a carbon filter and HEPA  filters.
Normally, I would try to make a contraption of sort to fix things, but with these more recent California fires (and quarantine) that gave us the APOLCALYPTIC orange sky, I had to do something more serious and effective. We’re in our 50’s and 70’s. We need to take extra care.

We keep all our doors and windows close and we don’t turn the heat pumps on unless it’s been over 100° outside, but I do go out several times to check on the chickens.

I can recommend the Honeywell HEPA filter units. My first one is at least 6 years old and still running (new filters though). We bought a second one last year. Spendy up front, but built to last.

Avoid the Honeywell electrostatic washable-filter units. They don't filter worth a darn. I finally threw out the electrostatic filter cartridges and duct taped a HEPA cartridge in place (thrift shop, sealed, $5, yeah baby!).

Nicole Alderman wrote:

John F Dean wrote:The post I am referring to was by Nicole Alderman in "Ways to cope with thick wildfire smoke"

The air filter actually works really well. Some people use only one filter, like this:



But, one filter makes the fan sad, and doesn't filter as much air. Two years ago, we made one with two filters:



This year we made it with three filters:



It helps if you can get filters that have one side that's the same size as your box fan's height. The ones we have are 20x20x1, and they work great. Get the highest rated filters you can, as the higher ones will filter more smoke out (but will be more expensive, and might be out of stock because other people might be buying them for the same reason). Any filter is better than none, though. Ours were white when we installed them over a week ago, and now the filters are grey. I've also taken to hanging my wet shirts or towels over the filters to dry. This seems to filter even more, without really taxing the fan too much. Our air quality has stayed great inside, even when it was at 225 outside. We also only entered and exited from the garage, using the garage as a kind of air lock. And, of course, we don't open the windows. And we've refrained from using the dryer or hood/bathroom vents. All of those send air outside, which means the house has to suck (polluted) air in from outside.

Of course, since we weren't exchanging inside air for the cooler outside air, our house has stayed pretty uncomfortable at 76-80 degrees, and I've had to run the portable AC unit (which sends hot air outside, and therefore sucks polluted air in) just too cool ourselves down. But, the box fan filter does a nice job of cleaning the air pretty quickly.

Last year, we leveled our air filter up even further, with larger air filters. We kept the giant thing stored in our wellhouse, and it was safe there for a year. We didn't need it for months, so I'd cut the fan off and used just the fan and left the filter part in the wellhouse. I was hoping we'd never need it this year, but our air quality has been unhealthy for two days. For the past 12 hours, it's been between 300 and 400.

Needless to say we taped it back together three days ago. The air in our house is nice and clean. This thing does it's job well!

It has filters on three sides, and the one on the back is super chunky. It takes up a lot of space, so it's taken over our recliner. But, I'll sacrifice the chair for clean air!

I like how we've used the same box fan with different filter configurations over the years. It allows us to upgrade when we have money for fancier air filters, and keep the air filters fresh. It's a win-win!

Nicole's fan is a great idea though in addition, every household would benefit from having these herbs mentioned here, Mullein, Hawthorn and Plantain (Plantago sp.):

Joylynn Hardesty wrote:Excerpt from this site: https://www.everygreenherb.com/smokeInhalation.html

"Mullein helps heal damaged lung tissue.
Herbs can really help to heal smoke damaged tissue and mucus membranes. Building immunity is also important for healing. Try astragalus, ginseng, yellowroot, and licorice tea or capsules. Eat oatmeal, yogurt, and bananas to soothe the throat.
Problems from smoke inhalation and second hand smoke
People with asthma, emphysema, heart disease, sinus problems, and allergies are especially prone to developing problems from smoke. Common symptoms from smoke inhalation and breathing second hand smoke include fatigue, coughing, throat irritation, watering eyes, sinus congestion, wheezing, shortness of breath, headaches, and nose bleeds.
Protect mucus membranes from smoke
Smoke in the air? Stay hydrated! Drink lots of water and herbal teas with lemon. Also drink mullein tea.
It may also help to irrigate the sinuses with a weak saline solution (salt water).
It is unpleasant but can bring relief to the sinuses – just snort some warm salt water from a bowl up into your nose then blow it back out into a tissue...."

And if tinctures is your thing... From https://www.aromaculture.com/blog/herbal-aromatherapy-for-smoke-inhalation

"My main allies throughout this fire season have been Hawthorn and Plantain (Plantago sp.) tincture. A dropperful of Plantain every couple of hours on the worst days has been helping to clear my symptoms quickly and on more mild days, a dropperful in the morning and one in the evening has been sufficient. After we come in from doing our garden chores in the mornings, I take a dropperful in orange juice and it has been tremendously effective for me. You could also consider using Nettle tincture, Mullein, or Marshmallow. The Plantain helps to soothe the mucous membranes and break down the excess mucous that accumulates because of the irritation caused by the smoke and inhaling other particles in the air. There are other herbs that can be used, but I have found that keeping it simple has yielded the best results for me, personally."

Southern Vancouver Island here.

HEPA filter inside the house: makes all the difference. Even though out house is older and not completely air tight, the filter has kept the air clear and breathable. Going outside, the smoke immediately burns the lungs and throat. Staying indoors when I can.

Outside, I have been wearing my N95 mask. I wear it when I am indoors with others or in crowded outdoor spaces (covid's unfortunately still a thing). But when it's pollen season or wildfire season, I wear it when I am walking to work, working in the garden, etc. It makes such a huge difference. One of the very small benefits of the pandemic I suppose has been discovering N95 and K95 masks — they are great!

A Corsi Rosenthal box will make a huge difference. 4or 5 MERV 11 or 13, at least 20 inch by 20 inch, cardboard, duct tape and a box fan. The shroud makes a big difference. 2 inch MERV 13 are best, but cost more. Cleanaircrew.org

Filters for home furnaces and HVAC systems come in a range of sizes and filtering capacities. For example, most of us grew up with those fiberglass filters that were good for filtering hair, cats and the occasional brick, providing the latter two don't hit the filter too hard.  EVERYTHING else passes.

HVAC systems tend to use filters that filter to a finer level than a furnace. That is so the coils of the cooling system do not become clogged with debris.

To rate filters, filter makers us rating systems. The MERV rating system (Minimum Efficiency Reporting Value) is common for our home units.

To filter smoke, you need a filter in the MERV 12 range and above.  HOWEVER, we can't just swap our stock filter for a MERV 13 and enjoy air scrubbed of bacteria, viruses, smoke and so on.  The system has to be designed for it, or the blower moving air will be worked too hard, even with a new filter, and will, eventually, die and early death.

Keep in mind, the more the filter loads up by scrubbing nearly everything drawn through it, the harder the fan/squirrel cage has to work to pull air though the filter.  For example, in my shop are three different dust collectors. One has two plastic bags to hold dust and chips collected from woodworking machinery, and two bags on top.  When new, the bags may only filter down to, say, five microns, but after the bags load with dust, they will filter at the level advertised, which is one micron. In other words, the dust collected blocks finer particles by serving as part of the filter media.

I have to beat on the bags to break much of the dust that builds up on them loose, so it will fall into the collection bags. I even have to shack the hole unit, because dust knocked off the bags collects on plates separating the filter bags and the collection bags. If I didn't shake the bags, the dust would stay on the plates and be drawn back up into the filter, reducing efficiency, though still filtering at the prescribed level.

To improve efficiency, the designer of my collector installed two upper filter bags. More filter area means the impeller can move more air, while filtering at the prescribed level of filtration.

My other collector is like the bag unit, but has two cartridge filters. They are much more expensive, but had at least twice the surface filtration area.  Even without using measuring equipment, you can notice the difference in how much better than the bag unit the cartridge unit moves air.

To monitor the air flow, which is determined by how plugged the filter(s) is/are, a simple manometer can be used. Alternatively, and the route I chose for my home HVAC and dust collectors, I'm using Magnahelic gauges, because they are easy to read.

To use either the manometer or the gauge, just note the reading on the gauge with a new filter installed, then change it when it appears the level of draw (vacuum) has climbed high enough, swap filters.

SIDE NOTE:  If installing a meter or gauge on a furnace of HVAC system, the pickup hose would go between the filter and the blower. For a dust collector, it would go on the intake.  Too, a home heater or heating and cooling system only needs a gauge that goes up to 1 w.g., while my dust collectors require something in the 15 or above range.

As noted, above, adding more surface area (like others showed they were doing with the box fan) allows air to flow easier, so you can go to a higher MERV rating.


My home filters are 5" thick and measure 20"x20".  By modifying the system so I can use three filters (side by side and not stacked), I can step up to a finer rated filter.

When configuring my home system, I can design it so it can, also, employ a cheaper filter to pre-filter the air using cheap disposable filters that prolong the life of the $50.00 filters.

In the end, a person could make one heck of an air scrubber for the house or shop and REALLY cut down on indoor pollution, and dusting.


One of many sites that gives information of MERV ratings:  https://www.grainger.com/know-how/equipment-information/kh-what-is-merv-rating-air-filter-rating-chart

NOTE: If you do chose to add a Magnahelic gauge to your system, buy it used from Ebay and save a fortune.  Alternately, you can build your own manometer with clean vinyl hose and colored oil or water.  Many sites show you how.

teas are all very well to relieve symptoms, but it's really important to stop the smoke as much as possible from entering one's lungs, because it IS carcinogenic, not so much because of the tree and plant fuels, but because of the manmade materials--housing, carpets, cars, tents, tarps, etc etc...that stuff is super bad and difficult to remove, once in one's lungs....

so, wear masks outside,  the smaller particle filtering and the more airtight, the better.

secondly, put a small micron size HEPA filter -down to 0.1 is best, and affordable- in each room (these filters don't filter as big a size as they are rated for).

it's not a lot to spend to safeguard one's health--which once gone, is waaaaay more difficult to restore, than good prevention.

Something that I find value in is defining the specifics of a problem if it has value.

When we talk about 'wildfire smoke' we are talking about something that has multiple elements to it all wrapped up into one. We could get really into the nitty-gritty if we wanted to but from a homesteader prospective, we can think of wildfire smoke in three parts for planning purposes. We are going to disregard, for simplicity, concentration of smoke in an area as well. If you have a super heavy smoke presence on your homestead, you probably are close to the wildfire and should consider your immediate safety.

Wildfire Smoke Components
A. Particulate Matter
B. Gasses (CO and NO2 among other hazardous air pollutants)
C. Water Vapor

Generally, when wildfire smoke comes in from a distance, I'm most concerned about A. when it comes to my own personal protection. If I am close enough to a wildfire to worry more-so about the generation of toxic gasses and steam, we have entered a different type of coping so I'm going to focus on Particulate Matter.

Particulate Matter

Particulate matter is a combination of solid/liquid material in the air. We are talking about inorganic compounds, organic compounds, chemicals, metals, dust, and other materials. Particulate matter in smoke is a hazard that can travel LONG distances. This is what gives smoke its haze that you see in the distance. Wildfire particulate matter contains fine material that has the ability to travel deep into the lungs and potentially into the pulmonary system. This is not to say that there is also coarse material present in the smoke, but it has layers of ick that can cause you issues. Please note, even a little amount of smoke particulates can cause respiratory distress and discomfort. If you can 'smell' it, it's a sign to consider taking action.

Things to do

Shoutout to the boxfan/filter system and the discussion of cloth masks. Both are excellent tools to mitigate both your personal exposure and reducing the settling of dust inside your living spaces.

If you have a little pre-planning and coin, I would like to steer folk's attention to purchasing and storing N-95 material masks.



N-95 masks are a useful respiratory protection device, when properly utilized, against particulate matter or aerosolized droplets. They do not offer protection against gasses (CO, NO2) so keep that in mind. The way that the masks are designed, they are exceptionally good at trapping particulates in their fibers. N-95s masks can be utilized until they become damaged, deformed, or are soiled. I have not had an issue in the past reusing masks when 'lightly' used. If you have trouble breathing after utilizing a mask for a while, it might be time to change it out. I do not recommend wearing an N-95 24/7 but if you are going to be in a smoky environment (outside?) then it might be value added to use them. When in the home, a box filter might be more comfortable/appropriate depending on your situation.

Safety Note
N-95s, in professional settings, come in a variety of sizes. At my work, we get fit tests for all employees yearly to ensure that the masks make an effective seal with the face. Facial hair being present where the masks contacts the skin of the face can cause air leaks. For personal use, you do not need a fit test but be aware that you may not get the full effective filtration rate of the mask if you do not have an appropriate fit.

We are about a month away from our wildfire smoke season.  At the local library, they often hand out little leaflets on how to keep safe during upcoming weather emrgancies.  like this (pdf) on how to get ready before smoke season starts.

There is some good advise in there.  here are a bunch more from part of the world that has regular smoke season of several weeks most years.