Wildfire Smoke: How It Impacts Air Quality and Your Health

Updated 8/10/2018

Firefighters continue to battle more than a dozen wildfires raging across California, including the largest in the state’s history, the Mendocino Complex Fire in Northern California. The wildfires have blanketed many parts of the state in smoke and ash, with smoke spreading all the way to New York City, nearly 3,000 miles away. The fires are making the air toxic to breathe due to dangerous quantities of particulate matter and VOCs.

Wildfire incident information

The Mendocino Complex fire is actually a merging of the Ranch Fire near Ukiah, California and the River Fire in Hopland, California. The Carr Fire is affecting Shasta and Trinity County near Redding. Other fires are located in Yosemite National Park and nearby national forests. Southern California fires near residential area include the Valley Fire (San Bernardino County), Holy Fire (Orange County), Cranston Fire (Riverside County), and Rangeland Fire (San Diego County).

For those in affected areas listed above, and for additional fire information, you can see the CAL FIRE complete list of major fire incidents and evacuation information here. For latest updates such as containment or evacuation info, you can also check this list of official CAL FIRE Twitter accounts.

Note that for select wildfire incidents such as Holy Fire and the Valley Fire, the lead firefighting body managing the incident may actually not be CAL FIRE but are being handled by the respective National Forest Department within the U.S. Forest Service (Cal Fire’s website will link you to the appropriate InciWeb page). Finally, you can click through the embedded wildfire map below for more details on the major wildfires burning in California.

Air quality a top concern

Air quality is a top concern for those in these and surrounding areas. Please check AirNow.gov and type in your zip code for the air quality in your area. The San Francisco Chronicle 2018 California Wildfire Tracker also has a helpful interactive map allowing you to display an up-to-date air quality visualization.

While some people may barely notice the smoke, others may find themselves struggling to breathe. Just how much you’re affected by the smoke depends on a lot of factors, including age, pre-existing health conditions and the density of the smoke in your area. Below, you’ll find information on the proper respirator masks to seek out, resources to check on air quality (both nationally and locally), and additional tips on reducing exposure to wildfire smoke.

What Is Smoke Made Of?

Wildfire smoke is a complex mix of carbon dioxide, water vapor, gaseous chemicals and particulate matter — a mix of solid particles and liquid droplets suspended in the air. The exact composition of wildfire smoke can vary depending on what materials are fueling the fire, how hot it’s burning and the weather conditions.

For people in close proximity to a wildfire, there’s a danger from breathing gaseous chemicals the fire emits. These include carbon monoxide, methane, acetic acid and formaldehyde.

But the bigger risk — the one that affects people far outside the immediate area of the fire — is particulate matter. The larger or “coarse” particles in smoke tend to irritate the eyes, nose and throat but generally don’t reach the lungs. It’s the “fine” particles, which are a fraction of the diameter of a human hair, that can really wreak havoc. These tiny particles can be inhaled deep into the lungs and eventually make it into the bloodstream, making healthy people sick and sick people sicker.

And it can be very hard to predict which way wildfire smoke will blow and how it will affect air quality. Smoke concentrations change constantly depending on weather, terrain, and many other variables.

How Smoke Can Harm Your Health

Poor air quality from wildfire smoke can affect people in a variety of ways. On the milder end of the spectrum, you may experience:

  • Burning eyes
  • Coughing
  • Wheezing
  • Shortness of breath
  • Runny nose

These symptoms are mostly caused by particulate matter irritating the mucous membranes and respiratory tract. The toxic gases in smoke — particularly formaldehyde and a gas called acrolein — are also respiratory irritants and can make these symptoms worse. Exposure to low levels of carbon monoxide can cause chest pain and irregular heartbeat in people with heart disease.

Who Is Most at Risk?

For people who are vulnerable, the effects of breathing smoke can be more severe.

In people with heart disease and chronic lung diseases like asthma and emphysema, studies have linked high levels of particulate matter with decreased lung function, worsening asthma symptoms, irregular heartbeat, heart attacks and even premature death.

Because the elderly are more likely to have pre-existing heart or lung conditions, they are more susceptible to the harmful effects of wildfire smoke.

Children are considered a sensitive population because their lungs are still developing. Exposure to smoke is especially dangerous for children with asthma and may cause more frequent or severe asthma attacks. But even children who don’t have asthma may experience shortness of breath, coughing and wheezing when exposed to smoky air.

While there isn’t a lot of research on the effects of wildfire smoke on pregnant women and their unborn babies, recent research has found lower birth weights after the 2003 southern California wildfire. The negative effects of cigarette smoke are also well documented. Since many of the toxic substances found in cigarette smoke are also found in wildfire smoke, pregnant women may want to take special precautions when the air is smoky.

How Can You Tell When the Air is Unhealthy?

If there are wildfires in your area and you can smell smoke or the air looks hazy or smoggy, air quality is probably poor. The EPA website AirNow provides real-time updates on air quality for the U.S. and parts of Canada. AirNow also has regularly updated maps showing where wildfires are currently burning and which areas may be affected by smoke plumes.

For people in the Bay Area being affected by the wildfires, the Bay Area Air Quality Management District provides local health advisories and air quality maps showing smoke impact zones. The Department of Emergency Management also offers the latest health advisories as well as tips for staying safe. Clean air shelters with air purifiers have been set up by the city’s public libraries, and as recently as last weekend, two more public locations have been added.

When to Limit Activity

The fires currently burning in California have had air quality index (AQI) levels at orange or higher in the last three weeks. This means that at minimum, sensitive groups like the elderly, children and people with heart or lung disease should limit time spent outdoors. Some areas have experienced red and purple AQI levels, which means the air quality is unhealthy for everyone. At these levels, most people will have some symptoms from the smoky air and should take steps to limit their exposure.

How to Reduce Your Exposure to Smoke

The two easiest things you can do to protect yourself when air quality is bad is to stay indoors and limit your physical activity. While this won’t provide complete protection, it will reduce your risk.

Other steps to take:

  • Keep windows and doors closed tightly, and run an air conditioner if you have one. Make sure the filter is clean and the unit is set to re-circulate indoor air.
  • Avoid activities that increase indoor pollution. This means no smoking, burning candles, cooking on a gas stove or vacuuming (which stirs up particulate matter)

Air Purifiers: What to Know

Air purifiers can be helpful, but they vary a lot in their effectiveness against wildfire smoke. HEPA filters claim to trap larger particulates (more than .3 microns in diameter), but cannot filter out harmful, toxic gases (VOCs). Activated carbon filters work for gases, but in smoky conditions, the filtering medium can saturate or “fill up” quickly and begin to re-release those toxic gases back into the air. If you are using a carbon air purifier, make sure to replace your filters very frequently when air quality is bad.

If you are considering buying an air purifier, you can learn about the benefits of Molekule’s new technology, which destroys pollutants instead of trapping them here. Molekule uses patented technology called PECO (Photo Electrochemical Oxidation) to capture, break down and eliminate fine particulate matter and gaseous chemicals. For more information on air purifiers and smoke, you can also read our blog post here.

If you live in a fire-prone area, it’s a good idea to have an air purifier and extra filters on hand before a fire breaks out. Once wildfires are burning, these items often sell out quickly and can be hard to find.

Should You Wear a Mask?

If you have to be outdoors, make sure you choose the right kind of mask and wear it correctly. Wearing a paper mask or a bandanna won’t protect you from the pollutants in wildfire smoke. Respirator masks labeled N95 or P100 can filter out fine particles, although they won’t help with gases in smoke like carbon monoxide, formaldehyde and acrolein.

Masks should be labeled with the acronym NIOSH, indicating they’ve been approved by the National Institute for Occupational Safety and Health. They’re available at many hardware stores and pharmacies, as well as online on sites like Amazon and Uline.

Make sure the respirator is fitted tightly to your face to prevent leakage. Men with beards may have leakage if the mask is against their facial hair rather than their skin. It’s important to note that these masks don’t come in children’s sizes, and a too-big mask isn’t very effective. It’s best to keep kids indoors as much as possible when air quality is poor.

Returning to Normal

As of this writing, firefighters are beginning to increase containment of the wildfires, while some have reached total containment. Even as evacuation orders are being lifted in select areas, we understand that things won’t simply return to normal for many of those affected. This checklist provided by Cal Fire has information for evacuees on what to do when returning home after a wildfire.

As a small San Francisco company, last year we did a little bit to help by donating Molekule air purifiers to shelters and firehouses throughout the affected area. This year we are gearing up for relief efforts. If you know of an evacuation shelter or charity working in the affected region that could benefit from a donated Molekule air purifier unit, please let us know, and we’ll do our best to assist.

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