How to stay safe in a smoky pandemic: Your questions answered, and science explained

By Erin Ross (OPB)
Sept. 14, 2020 1:26 p.m.

The smoke is getting better, but not as fast as we’d all like

Almost all of Oregon is covered in thick layers of unhealthy smoke. Researchers and health experts told OPB that having such high levels of smoke for so many people is unprecedented. In most of the West Coast, the air is not safe to breathe.

Experts can’t say it’s the worst smoke event ever to happen, but they all say it’s the worst smoke event they’ve ever seen or heard of — except, perhaps, smoke following the 2019–2020 wildfires in Australia. It’s certainly the smokiest Oregon has ever been.


Sunday, the air quality index approached “hazardous” across much of the state. While the air quality is expected to improve, it will remain unhealthy in many areas for at least the next few days. Changes in fire behavior, winds and the geography of certain areas could keep some cities and towns at unhealthy levels much longer.

We’ve put together a guide to some of the most common questions we’ve received about the health impacts of wildfire smoke, air quality, how to stay safe and how it all intersects with the coronavirus pandemic.

A lone couple takes in a smokey view at the Skidmore Bluffs, a usually packed overlook popular with picnickers taking in the sunset. Due to smoke blowing in from several surrounding wildfires, the air quality in Portland, OR been ranked the worst of all major cities in the world. Sept. 10, 2020.

A lone couple takes in a smokey view at the Skidmore Bluffs, a usually packed overlook popular with picnickers taking in the sunset. Due to smoke blowing in from several surrounding wildfires, the air quality in Portland, OR been ranked the worst of all major cities in the world. Sept. 10, 2020.

Claudia Meza

Who is affected by wildfire smoke?

Everyone is affected by fire smoke to some extent. But those with preexisting conditions like asthma, COPD, or lung disease are particularly at risk, as are the elderly. Those groups will also feel negative effects from smoke at much lower concentrations than people without preexisting conditions.

Clackamas County health officer Sarah Present is particularly worried about children, who she says are very vulnerable to complications from breathing smoke. “We’ve started thinking that they’re safe from COVID-19,” Present said, “but they’re very at risk from this.”

What are the health consequences of smoke exposure?

Most of the well-studied impacts of wildfire smoke exposure are on the short-term effects. Since smoke usually leaves an area after just a few days, there’s less information on long-term exposure.

Some of the health consequences are obvious: lungs hurt, your throat hurts, your eyes hurt. Smoke can also cause headaches, and in very high levels, nausea and vomiting.

But it doesn’t stop there. Research shows that ambulance dispatches and hospitalizations rise in as little as an hour after wildfire smoke arrives in an area. Other studies have found prescriptions for lung conditions, like asthma, rise dramatically as well. It’s the same for hospitalizations for asthma and other lung-related conditions.

Should people with heart disease or cardiovascular disease be concerned?

Your heart pumps blood into and out of your lungs to get oxygen, so just about anything that makes it into your lungs will also make it into your blood through your heart.

But it gets a little tricky. Dr. Joel Kaufman, a doctor of internal medicine and air pollution expert at the University of Washington told OPB that research on the subject of fire smoke and heart disease is mixed, with some studies finding an effect, and some studies not finding a clear link.

But there is a clear link between other types of air pollution and heart disease, which are much better studied. Kaufman recommends that people with cardiovascular disease consider themselves to be at a higher risk from smoke and other pollutants.

What do we know about wildfire smoke and COVID-19?

“This is a once-in-a-lifetime smoke event in the middle of a once-in-a-lifetime pandemic,” Present said. “I’ve never seen a public health situation like this.”

Little is known about how wildfire will interact with COVID-19, but scientists have a lot of concerns and educated guesses. The new coronavirus and wildfire smoke both impact lungs in similar ways. And we know people who have had COVID-19 can have lingering heart and lung complications, Kaufman said. Those complications would almost certainly make people more vulnerable to the effects of wildfire smoke.

There are also concerns about the effects of breathing smoky air may have on people with active COVID-19 infections.

“There’s that aspect that people who are sick with COVID, but maybe not sick enough to notice or go to the hospital. But then when you add smoke on top of it, it could kick them into an extra-bad respiratory response,” said Jeffrey Pierce, who studies wildfire smoke at the University of Colorado in Boulder.

Smoke can also harm your lungs' immune system, making you more prone to bacterial and viral infections.

Some researchers think wildfire smoke could make COVID-19 particles stay in the air longer and could be carried into nearby people’s lungs by the smoke. Kaufman doesn’t put much stock in this theory, but it never hurts to increase your social distancing and be extra careful.

Evacuees from the Santiam Fire continue to stream to the state fairgrounds in Salem on Thursday, Sept. 10, 2020, where county officials and the American Red Cross have established an aid center.

Evacuees from the Santiam Fire continue to stream to the state fairgrounds in Salem on Thursday, Sept. 10, 2020, where county officials and the American Red Cross have established an aid center.

Arya Surowidjojo

Should I wear a mask?

Absolutely. But the cloth masks and surgical masks that have become the norm during the COVID-19 pandemic have little impact on tiny particles of wildfire smoke, which drift on air currents and through the gaps in masks. Instead, respirators with changeable filters or N95, P95, or K95 masks work better.

Thick cloth masks that form a tight seal around your face can be effective, especially if they also have a place to put a replaceable filter to capture smaller particles. If your masks are loose, cut a wide band of nylon from a pair of tights and wear them over your mask. This helps create a seal and will filter more air particles (it’s a good COVID-19 tip, too.)

Remember to make sure that any masks you purchase don’t have one-way valves to let out air. While they’re great at stopping you from breathing in wildfire smoke, the one-way valves won’t protect others from any diseases you’re carrying.

And remember: even a cloth COVID masks is better than nothing.

If I have COVID-19 and I need to evacuate, what do I do?

Although cooler weather seems to be coming, it’s still the heart of fire season. Present said that throughout the last week, health departments in the Metro area have been in touch with people with confirmed COVID-19 and given them special instructions for evacuation.

If you suspect you have COVID-19 and haven’t been contacted by a health department, Present said not to go to evacuation centers. Instead, people should go to one of the hospitals or centers that county health departments have set up to help COVID-19 patients who need to quarantine outside their own homes. To find one of these centers, contact your local health department.

How can I keep smoke out of my home?


Keeping a home smoke-free is certainly easier said than done. Present suggests taping up windows, and putting wet towels under doors.

Central air conditioners have filters that can reduce levels of smoke. Some people might find keeping the fan in the air conditioner running helps lower smoke levels in the home. But if the air conditioning unit is in a smoky basement, smoke can get pulled into the air ducts after the filter runs. Play around with it: if your house gets more smoky, turn it off.

It can be a good idea to cover air vents in bathrooms (remember to put tape over the switch so you don’t accidentally turn it on.)

And remember: no home is perfectly sealed. If you turn on something that blows air out, like a bathroom vent, stovetop vent, or portable air conditioner, outside air will be pulled in through smaller gaps in a home. Play around with these, too. Some people might find that leaving a vent over a stove off lets smoke come in through the open ducts. Others might find that leaving one on dramatically improves indoor air quality.

What if I don’t have central air?

There are portable air filters available that can be very effective at clearing smoke and other pollutants from indoor air. Make sure that the filter says it’s “True HEPA” or can filter particles as small as .03 microns. Some products that call themselves “HEPA” aren’t actually HEPA-quality filters at all.

It’s important to make sure that the air filter does not produce ozone, and is non-ionizing. Ozone and ionizing air filters are used to disinfect spaces and clear out mold, bacteria, and viruses. But even small quantities of ozone can be dangerous. They are not meant to be used while people are around. If you can’t find a portable air filter, you can attach a HEPA filter designed for air conditioners to a box fan. It’s not as effective, but can remove significant amounts of particulates from the air, and make a noticeable difference.

Is there anything I should avoid doing to keep the air quality in my home from getting worse?

Present says everyone should avoid doing anything that can increase the amount of smoke in their home. Gas-burning stoves can produce particulates. In a normal situation, most people wouldn’t notice the pollution from a gas stove or oven, but in a smoke event like this, Present said, every little bit counts.

Present said to avoid burning incense, smoking indoors and lighting candles. If you don’t have central air with good filtration, it’s a good idea to avoid using pungent cleaning products until you can open windows, too.

Should I go for a run or recreate outside when it’s smoky?

“When people are exercising, they’re breathing a lot more air,” Kaufman said. And it can be hard to exercise while wearing a mask that protects against wildfire smoke.But while breathing smoky air is bad for your health, exercise is good for your health.

“It’s easy to stay inside for a few smoky days, but when the smoke lingers for weeks, it can be harder,” Kaufman acknowledged.

Exercise is a habit, so for some people, being consistent is important. Kaufman said that if someone does their personal calculus and decides going outside is worth it, “they should listen to their bodies.” If you start to get a headache, a sore throat, or feel ill, you should turn around and go back home.

The sun shines through wildfire smoke Saturday, Sept. 12, 2020, near Sisters, Ore. Wildfires have continued to wreak havoc statewide after a hot, dry, windy Labor Day weekend.

The sun shines through wildfire smoke Saturday, Sept. 12, 2020, near Sisters, Ore. Wildfires have continued to wreak havoc statewide after a hot, dry, windy Labor Day weekend.

Emily Cureton / OPB

How do we measure air pollution?

Air pollution levels are measured using an AQI, or Air Quality Index. The index indicates how unhealthy the levels of the particulate PM 2.5 in the air are by assigning it a number.

It’s not a mathematical scale. People understand big, round numbers, so the AQI categories are scaled to make it easier for the public to understand: An AQI under 50 is “healthy,” and anything over 100 is “unhealthy for sensitive groups.” The scale goes up in increments of 50 or 100.

It’s best to think of AQI in the same way as the hurricane scale. There’s not a magic switch that makes a hurricane more dangerous at one windspeed than another. Although there are parameters, hurricanes are ultimately assigned a category based on how much destruction they are expected to cause. Similarly, if you’re trying to take AQI and get actual PM 2.5 concentrations from it, you’ll get some really weird numbers.

What’s PM 2.5?

PM 2.5 refers to particles in the air that are smaller than 2.5 micrometers. There are one thousand micrometers in a millimeter, so these particles are too small to see. They can be produced by anything — usually, it’s industrial pollution, but right now the biggest producer of PM 2.5 is wildfire smoke. Unfortunately, really small things are really good at getting deep in our lungs, where they can make us sick.

How is AQI calculated?

Buckle up, cos we’re going to start talking about some really small numbers. Living in the U.S., we normally measure things in ounces and pounds, but scientists use the metric system.

First, a refresher: A gram is about the weight of a paperclip. There are 1000 milligrams in a gram. And there are 1000 micrograms in a milligram. So one microgram is about one millionth of a paperclip. We’re talking really, really tiny amounts.

AQI numbers correspond to certain densities of PM 2.5, and the health risks associated with those densities. The EPA says that people with sensitive lungs will start to experience effects if they’re exposed to more than 35 micrograms/cubic meter over 24 hours.

Since the EPA says that’s the level where the most at-risk groups start experiencing negative side effects, they gave it an AQI of 101. So anything above it has a higher number, and anything below it is lower.

So if the AQI is below 101, it’s safe for everyone to breathe outside?

There’s a catch. Kaufman was on a panel of EPA scientists tasked with reviewing the latest science on pollution and health.

“This 35 limit is supposed to protect the most sensitive people, but we know that it doesn’t,” said Kaufman. “And we know smoke and pollution affect sensitive people at levels much lower than that.”

Kaufman and the panel recommended the EPA make their air quality levels stronger, because research shows people with preexisting conditions can start experiencing effects at lower concentrations of PM 2.5, around 20 micrograms/cubic meter. The EPA didn’t take that recommendation.

What about long-term exposure?

Kaufman says that since smoke events are short-lived, it’s hard to have long-term exposure to wildfire smoke unless you’re actively fighting it. But there is research on other types of pollutants.

“With long term exposures, when sort of the annual average of air pollution is elevated in an area for the year, we see things like increased rates of chronic lung disease, we see an acceleration of heart disease risk,” said Kaufman. “There are now even concerns about increasing dementia risks with long term exposures to air pollution.”

The EPA calculates long-term exposure based on how much PM 2.5 people experience each day, once averaged out over the course of a year. The threshold comes out to a daily average of 10 micrograms/cubic meter of PM 2.5.

Since it’s an average, it is possible to exceed recommended long-term levels during a short-term smoke event. “If PM 2.5 levels stay over, say, 100 for a couple of weeks, that can raise the yearly average.”

That’s particularly true in the Pacific Northwest, where there is very little dependence on fossil fuels. Here, “wildfires are the biggest variable in people’s pollution exposure,” Kaufman said.