Wildfire Smoke: How To Protect Yourself

If you’re reading this article, you’re probably worried about wildfire smoke nearby. What can you do to protect yourself and your family? I’ve done a lot of research and blogging about air pollution, during my ten years living and practicing family medicine in Beijing, so I hope to share with you now how to protect yourself from wildfire smoke. I also have a sudden personal urge to share my advice, as I spent years in Santa Rosa training to be a doctor, and it’s been very distressing for me to follow the reports of the disastrous fires.

The major danger from wildfire smoke is from short-term health risks caused by the particulate matter from all of the burnt carbon. You don’t have to worry about the larger particles — the soot covering your car — as your nose and mucus in the lungs would trap and expel that. We would call them PM10 (Particulate Matter of 10 microns). It’s the smaller particles we worry about, the ones we call PM2.5 (Particulate Matter under 2.5 microns). These micro-soot particles are so small that they can diffuse directly down your lungs and get absorbed into your bloodstream. Once inside, they act basically as pro-inflammatory reactants, leading to all sorts of flare-ups of chronic disease — especially for the most vulnerable of us:

  • children with asthma or cystic fibrosis;
  • adults with lung disease like COPD and emphysema;
  • all elderly;
  • and anyone with heart disease, especially heart failure or with previous heart attacks.

Many people don’t realize that heart attacks are a lot more common during pollution spikes of PM2.5! As are ER visits for asthma exacerbation, bronchitis, and pneumonia – and unfortunately, a lot of premature deaths in people already very sick. All this is exactly why people with health risks should take wildfire smoke very seriously, even if it’s only for a few days. I welcome all of you to read about the Great London Smog of 1952, the most dramatic example of the dangers of short-term PM2.5 spikes, with thousands of premature deaths due to those dreadful five December days.

What To Do?

The general goal is simple: to decrease your exposure to breathing in all that smoke. How can we do this? I like to divide this into indoor and outdoor tips, to make it more useful. Let’s start with outdoor measures:

  • Monitor the AQI first. You need to know just how bad it is before you can make an informed decision. So you would follow the Air Quality Index, which is an hourly update from the EPA. You can find it on their website at airnow.gov or you can download an AQI app. My favorite AQI app is AirVisual, because you can see multiple cities at once (have fun comparing a typical day in Beijing to your town). You can also sign up for alerts via apps, SMS or the website.
  • Once you have that data, you can follow the EPA’s very handy chart below, offering advice for what do do depending on the AQI (here’s the PDF, and another guide for schools). For example, if the AQI is 150 (a typical day in Beijing but pretty bad for a wildfire), then everyone should be concerned, and those with health issues should probably not be outside much at all that day, and should closely monitor themselves for signs of ill health.


  • Decrease your outside exposure. This is pretty straightforward; if that AQI is over 100, certainly over 150, just spend less time outside. Generally speaking, indoor air in most homes is a natural filter, keeping out maybe a third of the outside PM2.5.
  • Decrease your exercise activities outside. When you exercise, you breathe much deeper and quicker than normal, and thus you’d be inhaling a lot more PM2.5 than from a simple walk. So if you still want to be outside, do less of your usual routine.
  • Wear a particle respirator (pollution mask) when needed. If you must go outside if the AQI is over 150, certainly over 200, you should definitely consider wearing a particle respirator — especially if you have any of those health risks I’ve mentioned above. I’ve done a lot of research on masks, including my own personal fit tests, and I think it’s a great idea to have a pile of disposable N95 respirators at home, and I personally would use them in Beijing when the AQI was over 150, certainly over 200 (which was quite often). And it’s not unreasonable at all to wear an N95 mask at lower AQI numbers like 100 if you have health conditions (like asthma) and need to be outside. If you want to read more about the science of N95 masks, you can read my review article here. Your hardware store and pharmacy should have a big pile of N95 masks, or you can buy online. There are a lot of models, and you can see the NIOSH-approved list of all N95 masks here I was always happy with 3M models.
  • Make sure you wear the mask properly. This is a big deal; if there’s air leakage, then it just doesn’t work. This is especially a problem with small faces such as a child; you can read my advice about pollution masks for kids here. Here’s a great infographic from AirNow about proper wearing of a respirator:


Now let’s switch to Indoor Tips:

  • Keep the windows and doors closed. Generally, indoor air is at least a third less than outdoor air — but you have to also be careful if your HVAC systems are pulling in air from the outside. You can read more about that issue from this EPA review starting on page 19.
  • Try to make a safe room. I think the most important room to purify is the bedroom, especially for children, as we all automatically spend 1/3 of our lives there. So, a huge percentage of your passive exposure to air pollution could be virtually eliminated if you simply had a decent HEPA air purifier in your bedroom, and kept the windows and doors closed.
  • Consider indoor air filters. A good HEPA air purifier definitely can make a huge difference, and they don’t have to cost a fortune. I’ve written multiple reports from Beijing on my own home testing of multiple brands of HEPA air purifiers, showing that even some cheaper models can cut down my indoor PM2.5 more than 90%. And there is some science backing up the use of indoor air purifiers to improve health outcomes (you can read more about that here). In terms of which brand to buy, I recommend you check out the reviews at the free consumersearch.com, and the paid Consumer Reports website. I would not rely on consumer reviews from Amazon, but of course that’s a great place to buy the machine once you’ve done your research.
  • Make sure you’re using the machine correctly. Are you sure it’s on the right setting? Have you estimated your rooms’ square feet and volume and bought a proper model for CADR? If you are overwhelmed with choosing, I recommend you read those two consumer sites above; also this awesome EPA wildfire article starting on page 20; and my guide to air purifiers (especially Step 1). And if you want to be super geeky to really make sure the machines are working well, you can buy one of the many portable PM2.5 monitors; the goal for healthy air would be a PM2.5 under 10 ug/m3 (equivalent to AQI under 50, in the “green zone” of healthy air).
  • Have a clean house. Do you love your candles? Wood stove and fireplace? How about that lovely smelling incense? Or a vacuum without a HEPA filter? Do you smoke? All of those can make your indoor air a lot worse than outdoor air.
  • Open windows when the air is cleaner. Let’s say there’s a break in the wind, and the AQI is under 50; it’s time to open all the windows and clean out all the stale air and indoor pollution — especially carbon dioxide, which can build up too high if a room or home is too tightly sealed up.

More Information

Every question you have is probably in the terrific wildfire PDF from AirNow.

My Bottom Line

You definitely don’t have to feel helpless, staring out of your window at apocalyptic sunsets and stressing out (assuming you’re far from the actual fire). Just follow as much of the advice above as you can, weather it out for a few days, and you’ll be fine. Maybe have some of these items ready now, in preparation for next year’s wildfire season. Good respirators and air purifiers can be quickly off of the shelves when these crises occur.

I’ll close with a photo of Sugarloaf Ridge State Park in Santa Rosa, my favorite hiking spot in the world which is now apparently a pile of black ash. You can see more photos here of spectacular Sonoma county.

Sugarloaf Ridge
Sugarloaf Ridge State Park, Santa Rosa. My “happy place” in my head whenever I need to relax…

Follow me on:
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Photography: richardsaintcyr.com

2 thoughts on “Wildfire Smoke: How To Protect Yourself”

  1. It did catch my attention when you said that you should consider wearing masks if you must go outside during a wildfire smoke and you have health problems. Actually, I’m an asthmatic person. My goal is to ensure that I can do my normal chores when a wildfire incident occurs, so I’ll be sure to shop for latex free smoke particle mask as early as now.

  2. Good idea to have N95 masks at home just in case. Looks like the rainy season is starting! It seems this wildfire problem will get worse over the next years with climate change.

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