My kids were born there, went to school there, and still live in the LA area. Like so many of our fellow Californians, they have been deeply impacted by the fires and the toxic aftermath. Wildfires expose everyone to multiple environmental hazards from combustion byproducts and particulate debris. These hazards are especially dangerous to people with asthma and other respiratory diseases. More than 25 million people in the United States, including more than 6 million children, suffer from chronic lung diseases such as asthma and another 16 million Americans have COPD (chronic obstructive pulmonary disease) related mostly to a history of cigarette smoking that we talked about last month. Another group at added risk is pregnant women. Women who are pregnant have higher metabolic demands for oxygen and breathe harder to keep up with it, pulling in more toxic fumes. There is also a significant risk to the developing fetus that can lead to low birth weight and preterm birth. The CDC published a pretty good guide that details all of these exposure risks to chemicals in wildfire smoke.
The air pollution from smoke and airborne particles generated by the fires is a toxic cauldron of petrochemicals, ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide. When wildfires burn up whole communities, particulate matter from chemicals, plastics, insulation, construction materials, and home furnishings is scattered into the air. This particulate matter carried in the wind poses a real public health threat from both short- and long-term exposures. While particles from wildfire smoke vary in size, about 90% of the particle mass emitted consists of fine granules that are about the size of a single human hair. These little beasts are coated with all sorts of noxious junk including acids (specifically sulfuric acid), inorganic compounds like ammonium sulfate, ammonium nitrate, sodium chloride, petrochemicals, organic chemicals, soot, metals, soil or dust particles, and biological materials such as pollen and mold spores. These tiny microscopic bombs find their way deep into the lungs and cause the symptoms of wildfire smoke inhalation that includes coughing, wheezing, difficulty breathing, chest pain, and chest tightness. Breathing enough of these airborne contaminants leads to an incremental lifetime risk for heart disease, lung disease, and cancer. Heavy exposure, especially in enclosed spaces like inside a home or airplane, can be deadly as the victim sucks in plenty of air but literally strangles from lack of oxygen. A document from the British Royal Aeronautical Society is another good reference regarding these risks.
The only worse thing than breathing some of this contaminated soup is breathing it in constantly and for prolonged periods of time. Emergency crews and firefighters who are already breathing hard from their exertion are at the highest danger of suffering long-term health problems from smoke and airborne debris. When exercising, you increase your air intake 10 to 20 times over resting levels. Increased breathing rates (called “minute ventilation”) bring more pollution deep into the lungs. People tend to breathe through their mouths during exercise, bypassing the natural filtering capability of the nasal passages, which adds up to more pollution in the lungs and also brings particles way deeper into the lungs, causing even more damage. Respiratory protection (those infamous “N1 masks” of the COVID era) can be useful for reducing personal inhalation of wildfire smoke and ash if used properly but also cause the user to rebreathe exhaled CO2 and other metabolic wastes your body is trying to get rid of. N1 masks also decrease oxygen intake with each breath, so rebreathing on top of limited 02 can lead to fatigue and shortness of breath.
Oxygen tank respirators, when available, will give some protection from this problem and also cut down on smoke inhalation but also only if used properly. That’s really important since correct use of tight-fitting particulate respirators certified by the National Institute for Occupational Safety and Health (NIOSH) is the only method that affords any real protection—check out information on their website linked here. Surgical masks are as useless for wildfire protection as they were for COVID protection. They are designed to capture infectious particles exhaled by the wearer (surgeon), not inhaled particulate matter or viruses. You breathe around these masks, not through them, so they afford virtually no air filtration and provide little or no protection from smoke inhalation or illness.
One of the ways to minimize these risks that’s unfortunately not available to rescue workers is to reduce outdoor physical activity. That will lower the dose of inhaled air pollutants and reduce health risks during a smoke event. Staying inside with the doors and windows closed can reduce the entry of outdoor air into your home, in some cases by a third or more. Homes with central air conditioning generally recirculate indoor air, though some smoky outdoor air can still be drawn inside. Other things you can do is upgrade the filters in your central air systems to high-efficiency filters that rate a Minimum Efficiency Reporting Value (MERV) of 13 or higher, so stock up on filters ahead of wildfire season and change them often, and turn off fresh air intake valves. Minimize indoor sources of air pollution such as smoking cigarettes, using gas or wood-burning stoves and furnaces, spraying aerosol products, frying and broiling meat, burning candles and incense, and vacuuming, since all of this will increase indoor particle levels. These are some of the same pollutants that are present in wildfire smoke—don’t double up on your risks. Stay informed about the Air Quality Index (AQI) during wildfires—there’s a government website that provides 24/7 updates for your area. The index is pretty simple; the higher the pollutant levels, the higher the number on a scale from 0 to 500, and it’s color-coded to indicate when the air is more or less harmful to you. Readings over 100 are unhealthy and anything over 300 means that the air is downright toxic. Keep checking the air quality, since smoke particles can linger long after the flames go out, even if they’re not as visible.
For those of us operating aircraft in the vicinity of fires, the standard weather TAF and METAR contain abbreviations such as FU, indicating smoke (from the French word for smoke, fumée), and VA, indicating there’s ash in the air. The particulate matter in the air can shut down our aircraft’s power plant, and it’s essential to be aware of the risks of flying through smoke-laden air, which can affect both turbine and piston motors. It can also stick to the leading edges of your wings, and the acid on the particles can corrode the surface, degrading the aerodynamic properties of the airfoil.
There are severe late risks of this toxic material in the air when the weather changes to rain that washes the fallen debris down from the hills. The LA Times reported that “due to recent rainfall and the increase in fire debris along beaches and ocean waters, an Ocean Water Closure has been declared. Fire debris runoff and pollutants in the water and on the sand may contain toxic or carcinogenic chemicals.” There are long-term implications of this wash-out since the toxic sludge runs into the coastal water estuaries and pollutes our marine wildlife. It also seeps down into the soil and is absorbed by farmland and local neighborhood vegetation and eventually becomes part of our diet.
Stay out of the smoke as much as possible, be smart and don’t breathe it, don’t fly through it, and as always, Fly Safe!
