Missoula City-County Health Department COVID-19 Information

Joint Information Center: Community COVID-19 Information and Resources

Information on Missoula County offices reopening to the public Monday, June 1

Missoula County phones: Missoula County continues to experience a high volume of calls. You may get a busy signal or experience long hold times when you call. Staff are working on solutions to decrease wait times. You may be able to find what you need at Thank you for your patience.


 August 17, 2017 Lolo Peak Fire

Lolo Peak Fire, August 17, 2017. Photo by Shannon Edney

This Page is Under Construction. 

Come back soon for more handy smoke-ready resources!



Climate Smart Missoula's wildfire smoke pages:

Includes great resources and some recommendations for creating cleaner indoor air spaces as well as info about air quality and health.

More coming soon!

Handouts (pdf downloads)

Using your central air handler to create cleaner indoor air (Source: Climate Smart Missoula)

Residential Guide to Air Cleaners in the Home (source: EPA)

More coming soon!

Smoke-Ready Blog - 2019

Use these links to skip to the blog post you want to read!

6/26/19: It's time to become wildfire smoke-ready! 

7/9/19: Creating cleaner indoor air with portable air cleaners 

7/18/19: Using your HVAC system to clean your indoor air

7/23/19: Coping with smoke and heat

July 23, 2019

Coping with smoke and heat

Full disclosure: Savvy smoke-ready blog readers will realize I basically used this same post last year. That’s what we call efficiency!

Did you go outside today?  The temperature actually hit 90 degrees.  It’s been a pretty cool summer, but we’re finally seeing some seasonal temperatures.  And while the summer hasn’t been a scorcher, I already installed my window air conditioner (my cat is old and ever-so-fluffy, and I fuss about leaving her to her own devices in the hottest part of the day. Hyper-vigilant pet parents unite!).


We’re likely to continue to see temperatures bouncing up to 90 or hovering in the mid-80s for a while. Even if you don’t have a geriatric fluff ball at home, that means it’s time to talk about air conditioning.  And smoke!  There’s always a way to work smoke into a conversation.  This is why air quality specialists make terrific (or terrible) dinner guests. 

With the potential for some seasonal temperatures and the likely return of wildfire smoke in the coming weeks, it’s important to make plans for keeping your house cool.  According to the Centers for Disease Control, every year more than 600 people in the United States are killed by extreme heat.  However, heat-related illnesses are preventable, and one of the steps you can take is cooling your home. 

I would be remiss in my air specialist duties if I didn’t remind ya’ll that air conditioners can be energy hogs, which is a no-no when we’re trying to confront climate change by reducing energy use.  However, your health is crazy important, so I’m not going to tell you not to use it.  Do try to limit your air conditioner use to the amount needed to keep your house at a safe temperature and as smoke-free as possible.  Climate Smart Missoula has some nifty tips for keeping your home cool(ish) in the summer: 

Do you have central air conditioning? Awesome!  If possible, bypass the fresh air intake when smoke arrives, upgrade your system’s filter (see last week’s blog post), keep your doors and windows closed, and enjoy the cool, clean air.  Also, maybe invite some friends or relatives over to share in your bounty. 

A lot of us do not have central air conditioning.  That leaves us with window air conditioners, portable air conditioners (those rolling things with giant hoses that send exhaust out the window), and the good old-fashioned method of opening windows at night and using fans to push hot air out and draw cool air in. Whichever method you use is personal preference, but the tricky thing here is smoke infiltration.  Opening windows at night works pretty well when it’s not smoky.  Unfortunately, the nice cool air that is so refreshing at night is the same cool air that traps smoke near the valley floor.  It’s not uncommon for us to see thick overnight smoke, and that smoke will move right into your home when you open your windows.  If you have no other option, it may be best to open your windows for long enough to cool your home, and then, once you’ve closed the windows, crank up your portable air cleaner(s) (PACs) to remove the smoke.  It is very important to avoid heat stress.  It can feel like a lousy bargain – clean air or cool air, but if you have an appropriately sized PAC with HEPA filtration on hand, you should be able to clean the smoke out of a room relatively quickly. 

And now, a brief foray into window and portable air conditioners.  First, we need to talk very briefly about how air conditioners work.  Disclosure: I am not an air conditioning expert.  I don’t even play one on T.V.  I have, however, honed my googling skills.  After much trial and very little error, I recommend the search queries “How do window air conditioners work?” and “How do portable air conditioners work?” Don’t let anyone tell you we aren’t a full-service health department.

Moving on.

Air conditioners transfer heat from your inside air to the outside air in a process that involves a cool air cycle and a hot air cycle. In the cool air cycle, the air conditioner draws indoor air across cooling coils, transferring the heat from the air to the refrigerant in the coils.  The now-cooled air is released back into the room.  The heated refrigerant needs to be cooled down, so in a separate part of the machine, the air conditioner pulls outside air across the heated refrigerant.  The heat from the refrigerant transfers to the air and the machine sends the now extra-warm air back outside.  A properly installed window air conditioner should keep these two air cycles separate.  Inside air cycles across the cooling coils and is released back inside and outside air cycles across the heated refrigerant and is released back outside.

Here’s a nifty link to a site that describes the process in better detail:

Here’s a snazzy diagram for those of us who like our air conditioner explanations in picture form:

Because window ACs recirculate room air, they generally keep indoor air in and outside air out.  However, some models have a feature that allows the user to bring in fresh air.  Check your model for a fresh air intake and be certain to close it during a smoke event.  Also, you will want to make sure the area around your window AC is as sealed as possible to limit smoke infiltration around the sides of the machine.  Once the area around the AC is sealed, peer into your window AC through the room-facing vents.  Can you see sunlight? Some ACs have Styrofoam dividers on their insides, and the seams aren’t perfectly sealed.  These small cracks let in sunlight and are also likely to let in some smoke. Also, if you have a jerry-rigged setup such as a window AC unit in a side-sliding window, you may need to basically treat your window AC unit as an open window.  In general, it’s probably a good idea to keep an appropriately sized PAC running in whichever room has a window AC.

If you want to use your window air conditioner to help filter your indoor air, research your machine’s ability to function with an upgraded air filter.  Window air conditioners have filters, but they’re designed for catching dust and pet hair, not the fine particulate in smoke.  There are some aftermarket window air conditioner filters out there, but they can be a bit dodgy on specifics about particulate removal.  Also, you need to cautious about adding an upgraded filter to a window air conditioner because the increased resistance can put significant stress on the machine. If you choose to upgrade your filter, get the highest MERV-rated filter you can for your model of window air conditioner, and use your PAC with HEPA filtration to clean whatever is left over.

Because of their design, portable air conditioners can be used with more window types than a window air conditioner, so they may be an option worth considering if you have side-sliding windows.  However, they tend to be considerably more expensive than window air conditioners and not all portable air conditioners are created equal.  Portable air conditioners come in two types: single and dual hosed.  In both types, the hoses bring in outdoor air to cool the refrigerant and send heated exhaust out the window. A single-hosed portable unit will use the same hose for both intake and outtake.  Because it can’t draw in enough outdoor air to cool its refrigerant, the single-hosed unit will also draw in your nice cool room air to cool itself down and send that air out the window.  This could be problematic during fire season, because the process creates negative pressure in your home.  The negative pressure will pull outside air into your house through various nooks and crannies, and if it’s smoky outside, it may also pull smoke into your home.  Dual-hosed portable ACs avoid the negative pressure issue by having a hose dedicated to drawing outside air into the machine to cool the coils.  This way, only outside air is exhausted out the window – inside air stays inside and the pressure in your house should remain stable.  However, dual-hosed portable air conditioners tend to be quite a bit more expensive than single-hosed machines.  If you are using a portable air conditioner, try to seal the edges where the exhaust plate meets your window as much as you can.  Otherwise, there’s a good chance smoke will sneak in around the edges.   Use your PAC to clean out whatever smoke ends up inside.  This will be particularly important if you have a single-hosed portable AC. 

The take home message is this: You need to be able to cool your home, and there’s a good chance the process of cooling your home will introduce smoke into your breathing space.  If you have a PAC with true HEPA filtration you can reduce the amount of smoke that stays in your home.  In 2017, Climate Smart Missoula ran particulate sensors in a house that did not have air conditioning but did have PACs with HEPA filtration.  Yes, smoke came into the house overnight when smoke rolled into town.  However, within a couple hours of closing the windows and turning on the air cleaners, that house had some of the best air in Missoula. 

If you don’t have air conditioning and, based on your health, you can’t allow any smoke into your home, your best option may be to find somewhere else to be next time smoke rolls into town.  You may need to stay somewhere local with air conditioning and filtered air or leave the valley to find clean air. 

Stay cool and breathe safe!

July 18, 2019

Using your HVAC system to clean your indoor air

In my last update I wrote about using portable air cleaners (PACs) to create cleaner indoor air during smoke events.  Typically, folks will use PACs to clean individual rooms.  For those who want to have cleaner air throughout their entire house, they will either need to purchase multiple PACs or use their central air handler or furnace fan to push air through a filter and distribute the air throughout their home.

(If you decide to go the PAC route, know that a PAC isn’t going to move air throughout the house.  If you place a PAC in the living room, it’s not going to do a great job cleaning the air in the bedrooms down the hall even if the PAC is rated for a really large space and the doors are left open.  Air just doesn’t corner very well.)

Now, before we get into this, here is my disclaimer: I am not an HVAC technician.  I’ve spoken with some folks who know things and I’ve done a lot of reading, but this does not make me an expert. If you have questions about your specific air handler/furnace/air conditioner, etc., please talk to your HVAC technician.

Alrighty.  Let’s go.

It’s becoming more common these days for homes to be built with HVAC systems (heating, ventilation and air conditioning) that use central air handlers for cooling and/or heating. In addition to impressing the socks off this Montana child of the ‘80s (Air conditioning in a house???  That’s some fancy stuff right there!), the filters on air handlers can be handy tools for cleaning indoor air throughout your home during a smoke event.  Your duct work will deliver air to each room, which solves the cornering problem PACs face.

Note that If you have central air for heat, but not air conditioning, you can still clean your indoor air by turning your furnace fan on without the heat.

To get started, we need to dig into HVAC filters.  First, find where your filter(s) are housed in your HVAC system (note that some homes may have more than one air return and corresponding filter). Look at your filter.  Is it a flat panel? Is it washable?  Is it something you’d take outside, hose off and return to its casing? If so, and if want to use your HVAC to clean your air, you need a different filter.  A better HVAC filter will have a whole bunch of fabric pleats and cannot be washed.  Note that even if you have a filter with some pleats and you wouldn’t dream of washing it with a hose, there’s a good chance the filter currently sitting in your air handler is not going to remove fine particulate matter from smoky air.  Homes will generally have a filter that is MERV 6 or less, and you need to upgrade to at least a MERV 13 to get a filter that has been tested and shown to remove the tiny particles in wildfire smoke. 

What’s a MERV, you ask? Well, gather round and let me tell you more than you ever knew you wanted to know about filters!

MERV stands for Minimum Efficiency Reporting Value.  It was developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) to evaluate air filters.  The MERV ratings classify a filter’s ability to capture different sizes and amounts of particles at each pass.  For example, a MERV 3 will effectively filter large particles, such as cat hair and the bits and pieces of insects that end up in HVAC systems.  No one wants to inhale bug parts, but these are not the particles we’re concerned about during wildfire season. With each pass, a low-rated MERV (1-4) will filter less than 20% of coarse particles that are 3-10 microns in diameter (like road dust) and won’t do anything to stop the fine particulate in smoke.  A MERV 13, meanwhile, will remove about 90% of all particles larger than 1 micron in diameter and will remove about 50% of fine particles 0.3-1 micron in diameter with each pass.  MERV 17-20 gets into HEPA range, with greater than 99.9% of all particles 0.3 microns and larger being removed with each pass.  High MERV ratings (15+) are typically found in hospital and surgery settings. If you’re craving more numbers and details, here’s a link to a handy dandy chart: If you’d like to know more about MERV and how filters are tested, here’s a useful (if somewhat technical) article from the National Air Filtration Association, helpfully titled “Understanding MERV” :

The good news is, a lot of stores sell MERV 13 filters.  The bad news is, it can be hard to find the MERV rating on consumer-grade filters.  Both 3M and Home Depot have created their own scales to describe their filters’ efficacy (MPR filters and FPR, respectively), and they don’t correspond perfectly with MERV ratings.  This is, for the savvy filter consumer, horribly unhelpful; it makes it difficult to compare filtration across brands.  The MERV scale is the official metric used to measure filters’ effectiveness, and even though these brands display their own scales to customers on their packaging, everything comes back to MERV.  If you want to take a deeper dive, this (dare I say sassy?) blog post from a filter delivery company delves into MERV, MPR and FPR:

I have had some success finding the MERV ratings by examining the fine print around the edges of filters.  In general, the best consumer grade filters sold by 3M (MPR 1500+) and Home Depot (FPR 10) will be MERV 13s.

Before you start using your central air system to clean your indoor air, there are some things you need to know and steps you need to take:

1.       Can your HVAC system handle a better filter?

Not all furnaces or air handles can deal with the added resistance from better filters.  The better the filter, the harder it is to pull air through it. Folks in the HVAC world call this the “pressure drop.” As you increase MERV, you also increase pressure drop.  If you aren’t sure if your HVAC can handle a better filter, talk to your HVAC technician.

2.       Thicker filters are better (but also more expensive).

Thick pleated filters (4 to 5 inches deep), will allow greater airflow through your air handler than 1-inch pleated filters.  This will reduce the energy required to pull air through the filter and will help with concerns about pressure drop.  Not all air handlers will have slots for these thicker filters, but if you can, aim for a thicker filter.

3.       Install your filter correctly.

There is an arrow on your filter.  It needs to point in the same direction as the airflow.

4.       Can air sneak around your filter? That’s a no-no!

Once you’ve slid the new filter into its slot, take a good, hard look at it.  Is it loose? Can air easily bypass the filter?  If air can move around the filter instead of through the filter, you won’t get much benefit from your fancy new filter.  You’ve basically put up pretty curtains but forgot to close the window.  Filter bypass is often caused by poorly fitting filters, poor sealing of filters in their frames, and leaks and openings in the air handler between the filter and blower. Even tiny gaps can reduce your filter’s effectiveness, so make sure your filter is the correct size for your air handler and is properly seated in the filter housing. You may need to seal up gaps that let air bypass the filter. (This is also a great opportunity to channel your inner Gandalf and yell “You shall not pass!” at the incoming air.  You know.  If you’re into that kind of thing.)

5.       Buy extra filters and be ready to change your filter mid-fire season.

Plan ahead and have extra filters on hand.  Better filters are great for improving air quality, but because they catch so much more material, they get dirty pretty fast. If we have a prolonged smoke event, there’s a decent chance you’ll need to change your filters after a couple weeks. Stock up now, and If we get lucky and dodge the bad smoke again this year, you’ll be ready to go for next year! 

6.       Close your windows and doors and seal up leaks to keep smoke outside.

You need to keep exterior doors and windows closed and seal up air leaks that let smoke sneak in.  A typical older home will let in about three times as much outdoor air through little air leaks compared to a new Energy Star home.

7.       Set your fan to “On” instead of “Auto.”

You will only receive cleaning benefits while the fan is running.  If you have your thermostat set to “Auto,” you’ll only see sporadic air cleaning.  Studies have shown that PACs with true HEPA filters are more effective at creating cleaner indoor air in a residential setting than central air systems, because PACs are more likely to be run continuously (unless they’re super loud. For more on that, see the previous blog post).  If you want to use your central air system to clean the air, you need to keep the fan on.  This will increase energy costs.  Happily, in Montana we don’t have year-round wildfire seasons.  Yay, winter!

8.       Keep interior doors open.

You’ll want to keep the interior doors open to avoid creating negative pressure in your main living space.  Your HVAC system likes balance – it pushes air into rooms and pulls air back into the air handler. If your return air vents aren’t getting air from the rooms with air supply vents, the HVAC system will pull air into your house to make up the difference.  This is super not helpful during a smoke event.  (Note that this scenario is more likely in older homes with a centrally located return vent.  Newer homes are more likely to have return vents in multiple rooms and halls.)  It’s a good idea to take a quick walking tour of your home to identify the air supply and return vents.  Your supply vents will have louvers and will blow cold air when your air conditioning is running.  Your return vents will likely be located near (or in) the floor, don’t have louvers and will not blow cold air.  To keep your system balanced, make sure your supply air will make it to a return vent.

9.       Find and replace all your filters

If you have multiple return vents, you may have multiple filters to replace.  The filters in HVAC systems are placed so that the return air is filtered before being sent into the air handler.  This keeps random contaminants, pet hair, bug parts, etc. from gumming up the works in your air handler.  If you aren’t sure where your filters are located, you can tour your HVAC system or ask your HVAC technician.  To help you get started, I googled “Where are the filters on my HVAC?” and found the following links helpful.  Got an HVAC question? Let me Google that for you!

(Note: a lot of these links go to company blogs.  This is not an endorsement of any single product.)

Here's a nice handout from Climate Smart Missoula that summarizes the previous 1800 words or so. 

Coming up next week: things to know about air conditioners!  Just in time for the coming heatwave.  Holy cats, it’s about to get hot.

July 9, 2019 

Creating cleaner indoor air with portable air cleaners

Did Sunday’s sunset look a little too pink to you? Did it make you stop and say, “Hmmmm,” and then maybe start obsessively looking at heat detection maps and satellite photos to figure out where the smoke was coming from?  Then congratulations! You, too, could be an air quality specialist! 


There’s some high-level haziness in the air from far away wildfires.  It hasn’t impacted our air quality, but it’s a good reminder that even though so far, we’re having a cool, wet summer, other areas are already on fire. (Looking at you, Alaska.) 

It’s also a good reminder to start preparing now for wildfire smoke season! 

To begin, if you’re going to get serious about having cleaner indoor air when wildfire smoke comes to town, you need to take steps to keep the smoke out in the first place. A well-sealed house will act as a barrier to slow smoke’s entry.  If you have leaky house, you can see so much outdoor air coming inside that you effectively have a small window open 24/7.  If you have a hard time keeping your house warm in the winter and deal with a lot of cold drafts, that’s a good sign you have a leaky house.  Sealing up your house will save energy and slow smoke’s entry during wildfire season.  Win, win!  Of course, eventually even a well-sealed house will see some smoke make its way inside, so it’s important to think of how you’re going to clean the indoor air. 

We’re going to kick that conversation off with portable air cleaners (PACs).  You may be more familiar with the term “air purifier.” While manufacturers advertise their machines as air purifiers, it’s more accurate to call them “air cleaners.”  You can’t really purify the air, but you can make it cleaner. Most government agencies and academics have adopted the terminology “portable air cleaner.” Not only is this a more accurate description of the machines, it also comes with a nifty acronym, that’s fun to use and say.  So, PACs it is! 

For the purposes of this blog, I’ll be focusing on PACs that clean the air using a true HEPA filter.  There are also PACs on the market that use electrostatic precipitation (ESP) or ionization to remove fine particulate matter from the air, but these technologies can produce ozone, which is terribly unhealthy to breathe.  Know what you don’t want from your air pollution-cleaning machine? Air pollution.  ESPs trap particles on plates that need to be cleaned and ionizers make the particulate drop from the air to stick to surfaces in your home.  There are several ESPs and ionizers on the market that produce low levels of ozone.  If you’re looking into one of these machines, check to make sure it’s on California’s list of Certified Air Cleaning Devices.  California will only certify PACs that produce ozone concentrations less than 0.050 parts per million, which is just below the national ambient air quality standard for ozone (0.070 parts per million). 

Alrighty.  Back to HEPA filter PACs. 

First off, what they do isn’t particularly complicated.  At its core, a HEPA PAC is a fan and a filter.  The fan pulls dirty air through the filter, the filter traps airborne particles and cleaner air exits the machine. Easy peasy. There are a lot of different styles of HEPA PACs on the market with various bells and whistles, but the fan and the filter are the primary components.  Note that while there are PACs that will clean a small bedroom in the $100 range, you can easily spend a lot more than that on a machine with more features and a larger cleaning area. 

HEPA PACs can be incredibly effective at removing particles from indoor air, but you need to do some due diligence and use them properly to see indoor air improvements. 

For HEPA PACs to be effective, they need to have a true HEPA filter, be sized appropriately for the room that they’re in, and they need to be turned on – ideally, all the way on.  You get the most cleaning benefit when you crank the fan all the way up.  This is where studies looking at PAC effectiveness run into the occasional example of less-than-stellar performance in the real world versus in the lab.  Some PACs make a lot of noise when turned on to their highest setting, and that’s when they get turned down or off by people tired of listening to the loud fan.  Turns out, turning a PAC off just kills its effectiveness. If you’re concerned about noise and have some extra dollars to throw around, consider purchasing a PAC sized for a larger room than the one you put it in – this way you should be able to still get a significant cleaning benefit at a speed other than “supersonic jet.”  Another option is to turn your PAC to its highest setting when you aren’t in the room you’re cleaning.  If your PAC is in your bedroom, turn it all the way up for a couple hours before hitting the sheets.  Provided your room’s doors and windows are closed and not terribly leaky, you should have decent air to start the night and be able to reduce the fan speed on the PAC to a more tolerable level. 

Now that you’ve figured out what noise level you’re ok with, you need to stock up on HEPA filters. If we have a bad wildfire smoke season, you’re probably going to want to change the HEPA filter in your PAC midway through the season.  I know most HEPA filters say they’re good for six months to a year, but that’s for normal air quality. Wildfire smoke is not normal air quality.  When filters become clogged with particulate, air can no longer pass through them.  You know how Jurassic Park taught us life will find a way?  Air will also find a way.  Once the air can no longer go through the filter, it will go around the filter.  You’ll likely still have air coming out of the machine, but it won’t be clean air.  When the Health Department got our PACs back from the Seeley Lake and Lolo schools following the 2017 fires, the used HEPA filters were black and the insides of the machines were coated with soot left by air sneaking around the clogged filters.  That was an extreme fire season, but it was instructive. Now we stock up on HEPA filters.  You should, too! 

If you choose to get a PAC, plan on keeping it in the room where you spend the most time.  For example, it’s a good idea to run a PAC in your bedroom while you sleep.  Also, keep windows and doors to the room with the PAC closed to allow the machine to recirculate the air through its filter multiple times an hour. 

Keep in mind that HEPA filters do not remove the volatile organic compounds (VOCs) in smoke.  VOCs give smoke that campfire smell we all know so well, and they can make you feel pretty crummy.  While we generally consider the fine particulate matter in smoke to be the greater public health threat, VOCs are nasty business.  They’re also harder to remove from the air.  Generally, PACs with robust filters or technology to cut down VOCs will be quite a bit more expensive than your basic HEPA PAC.  A lot of HEPA PACs come with thin activated carbon pre-filters that are advertised to remove VOCs, but again, that’s for background concentrations.  The levels of VOCs in wildfire smoke will quickly saturate a thin prefilter. 

Important questions to ask when you look at an air cleaner:

  1. Does this unit use a true HEPA filter?

There are “HEPA-like” filters on the market, which are not the same thing as true HEPA and won’t be as effective at removing the fine particulate in smoke.  Remember, the fine particulate in smoke is less than 1 micron in diameter!  You want a filter that will remove the smallest particles possible, and that’s a true HEPA.

  1. How many square feet will it cover?

If you end up with an undersized air cleaner that is unable to recirculate the room’s air through its filter 2-3 times per hour, you likely won’t see significant indoor air quality improvements.

Also, keep in mind that the effective cleaning area is based on a room with 8-foot ceilings.  Do you have a luxuriously tall or vaulted ceiling? Fancy! Also, you’ll need to get your hands on a bigger air cleaner.  The more air you need to push through the filter, the larger machine you’ll need to purchase.

  1. Does this unit produce ozone?

Some air cleaners produce ozone, which is a criteria pollutant and harmful to human health.  Check to make sure the unit you are interested in has been approved by the California Air Resources Board (CARB) here:  The CARB only approves units that do not produce harmful levels of ozone.

 Good questions to ask:

  1. Is this unit Energy Star rated?

Using less energy is good for the planet and your wallet!

  1. Is it noisy?

A PAC is only effective if it’s turned on, and it’s most effective if it’s turned all the way up. If you’re sensitive to noise, you’ll want to look for quieter models.  No matter what, expect some level of noise when you turn your PAC all the way up.  Fans can push a lot of air, and that will tend to generate noise.

  1. How expensive are replacement filters?

Do some legwork and find out how much the manufacturer charges for replacement filters.  You may also want to investigate filters offered by third parties. There are several companies making HEPA filters that will fit popular PAC models, and they often cost less than manufacturers’ filters.  Keep in mind, using third party filters may void the PAC’s warranty. 

Valuable question to ask:

  1. How effective is the unit at removing volatile organic compounds (VOCs)?

There are multiple methods for removing VOCs, but the most common one you’ll see is an activated carbon prefilter.  While activated carbon can remove VOCs, be aware that it can get saturated pretty quickly, which limits the effectiveness of a lot of the carbon prefilters on the market.  If you are concerned about the VOCs in smoke, you can plan on changing the prefilter out frequently or you can invest in an air cleaner with a robust activated carbon filter.  Note that the hefty activated carbon filters can be quite pricey.  Typically, the more fancy the VOC removal, the more expensive the machine (and the replacement filters).  For some folks, though, removing VOCs will be worth the price.

 That’s it on PACs for now.  Coming up in the next blog: using your central air handler for creating cleaner indoor air!


June 26, 2019 

It's time to become wildfire-smoke-ready!

This is the first post in a short series of blogs about becoming a smoke-ready community. Stay tuned as we prepare for wildfire season!

Oh, hey! It’s suddenly summer!  Have you bought a new HEPA filter, yet?

That was one long, cold slog through spring, but summer has finally arrived, and we can get started on our summer to-do list: get outside and grill delicious foods, spend time on the river, hike in the mountains, enjoy the extra hours of daylight, and make a plan for creating cleaner air spaces in homes and businesses before wildfire season hits!

That’s right, folks.  There’s lightning in the hills and we’ve got smoke on the brain.  It’s time to become Smoke Ready. (It’s capitalized so you know it’s important.)

Wildfires in our region typically start in mid-July or August, and the clock’s ticking for getting ahead of summer wildfire smoke. Over the next couple weeks, I’ll be sending out some helpful information for preparing for this year’s wildfire season.  Now, the good news is we’re not supposed to have an extreme wildfire season in western Montana this year.  It’s supposed to be an average fire year and a potentially cooler and wetter summer than we typically see.  (And yeah, that feels right.  I, for one, greatly resented turning my heat on in June.) Keep in mind, though, that 2017 was *supposed* to be an average fire year.  Also, know who’s predicted to have a bad fire year? Washington.  And who’s sent us some of our worst out-of-state smoke? Also, Washington.  And who’s already had a large grass fire year? Again, Washington. The point being, even if we avoid local fires (and that’s a big if), there will likely be smoke this summer.  I mean, Canada’s been on fire for over a month now. Overachievers, the lot of them.

Wildfire smoke is nasty businesses.  It’s composed of a veritable stew of chemicals and fine particulate matter.  Most of the growing field of wildfire smoke health research has focused on the particulate matter in smoke, and really, there’s no good news there.  The fine particulate matter in wildfire smoke is super tiny (typically less than 1 micron in diameter), and it can bypass all your natural defenses to get deep into your lungs and even enter your bloodstream where it sets off an inflammatory response.  The pollutant is particularly harmful to infants, children, pregnant women, the elderly and anyone with heart or lung disease. It’s also just bad for everyone, particularly if you’re stuck in it for days or weeks at a time.  Folks who are sensitive to the smoke are most likely to experience respiratory effects such as worsening asthma attacks or difficulty breathing.  There’s also an increased risk of heart attacks and stroke for those with heart conditions.  The increased frequency of long duration wildfire smoke events is a relatively new phenomenon, so we don’t yet know what the long-term ramifications will be for children exposed to smoke.  We do know from a study in California that young children (ages 0-4) had a greater spike in asthma-related emergency department visits during a 2007 wildfire than any other age group.

Also, have you noticed how everyone just starts to feel crummy when smoke drags on?  When you’re in wildfire smoke for a prolonged period your body goes on the offensive.  An inflammatory response is really your body trying to get rid of an invader.  The strategy works pretty well when the invader is biological (such as a virus), but it’s less effective against particulate matter.  Exposure to fine particulate matter essentially sets in motion a prolonged immunological response.*  You feel crummy when you have a cold because your body is fighting off the invader.  It’s basically the same thing with smoke (albeit with less mucus).  Unfortunately, despite your body’s efforts, the most effective way to really get better is to get out of the smoke.  

Happily, we know how to get out of the smoke! Or, more accurately, get the smoke out of our breathing space.  Unfortunately, just going inside isn’t necessarily going to cut it.  You know how the super tiny fine particulate matter can get into your bloodstream? It can get into buildings, too.  The best way to make sure your indoor air is cleaner than the outdoor air is to actively filter out the fine particulate matter.  Now, the good news is the technology to filter fine particulate matter exists.  This isn’t an unknown realm or impossible task.  It takes some planning and an investment in good filters, but most people will be able to create cleaner indoor air when wildfire rolls into town.

I’ll take you into the weeds of creating cleaner indoor air spaces over the next couple weeks. We will go over picking out and using portable air cleaners (PACs) with true HEPA filters, the dos and don’ts of using your central air system to clean the air, some practical considerations for dealing with heat, air conditioners and wildfire smoke, and what we know about creating cleaner indoor air in large buildings. 

(If you caught this series last summer, some of the material will seem awfully familiar.  Also, I’m assuming you dutifully went out and secured PACs to create a cleaner air room in your home or bought a better HVAC filter for your central air system last year.  If so, don’t forget to stock up on new filters for the 2019 wildfire season!)

Also, if you don’t want to wait for my next update, head on over to for some great tips on preparing for wildfire season!

*With thanks to Sarah Henderson of the British Columbia Center for Disease Control for that explanation of why we all feel miserable in the smoke.  Sarah Henderson is one of my wildfire smoke heroes.  And yes, that’s a thing. There are some super rad, passionate scientists working to advance wildfire smoke science. Also, it’s nice to know that Canada sends us excellent science along with all the wildfire smoke.