Pacific Coast Wildfires and Air Quality: Considerations for Pregnant Women

Wildfires are burning throughout North America, especially in the western part of the United States. Along with death, destruction of buildings, and evacuations due to the fires themselves, the smoke from the fire travels, affecting life in substantially larger geographic areas by ruining the quality of the air. In the Pacific Northwest, for example, where I live, air quality has been lousy for the past several days and is projected to remain dangerous until the end of the current week. This raises the topic of pregnancy during natural disasters; in this case, we have the wildfires superimpose on the COVID-19 pandemic.

If you are pregnant and located in any affected area, you may be wondering whether the pregnancy puts you at any particular risk from the bad air. The answer is yes. The US Center for Disease Control and Prevention considers pregnancy among various health situations that make one more sensitive to poor air quality. Air quality, in turn, is rated by government agencies in terms of what’s called the Air Quality Index (AQI), a number that increases as the air gets worse, which can happen due to wildfires of the type that are burning now, but it could also happen due other natural disasters, for instance volcanic eruptions. As the AQI increases, ‘sensitive individuals’, including pregnant women, tend to feel health effects before individuals who are not considered sensitive.

Supplied by the same weather services that give you updated information on air temperature, humidity, rain, and snow, AQI numbers are reported in ranges that are color coded as follows:

Green: 0 – 50. This range is considered good air quality, with pollution poses little or no risk.

Yellow: 51 -100. This range is considered moderate, acceptable air quality, but people who are unusually sensitive to air pollution may experience acute (short term) health effects.

Orange: 101 – 150. This range is considered unhealthy for “sensitive groups”, including anyone with a lung or heart condition, but if you are PREGNANT, you are considered to be part of this group, even if you do not suffer from any health condition. As for what this means in terms of specific health effects, much more study is needed, but it is thought that risks include both effects on the respiratory system of pregnant women and an increase in the risk of pre-term labor and birth, especially for those exposed during the second trimester.

Red: 151 – 200. This range is called “unhealthy”. Breathing such air, some otherwise health people (people with no medical conditions) may experience health effects, while members of sensitive groups (including pregnant women) may experience more serious health effects.

Purple: 201 – 300, “Very Unhealthy”. Health authorities issue alerts for the public as a whole as anybody can feel health effects from breathing the air

Maroon: Listed as 301-500, or 301 and up (AQI can exceed 500, but sometimes 500 is the highest value reported), this is called “HAZARDOUS”. The number of people suffering emergency conditions is expected to increase and everyone who breathes the air is likely to be affected in some way.

To give you are idea of how bad things are, at the time that I’m writing this, the most recently reported AQI in my region was 286, measured at 7 am Sunday morning. That’s in the “very unhealthy” category, and yet it was ‘good ‘news, because the night before it had reached 423, so many parts of the western US are well beyond what the danger limits for pregnant women. While a high AQI means that generally healthy people can develop problems that they will feel as breathing issues and irritation of their mucous membranes, generally it is thought that symptoms and other effects are temporary and will abate gradually as you breathe better air. Consequently, minimization of exposure is an important overall strategy.

What major factors go into the calculation of AQI?

One factor is particulate matter, also called particle pollution. In the current case, this means the concentration of tiny particles resulting from the incomplete combustion of trees and anything else that gets caught up in the wildfires.

Another factor is ozone (O3), or rather “ground level ozone”, since ozone is a gas that we need to have up in the stratosphere, where it protects us against ultraviolet (UV) radiation from the Sun, but it’s not something that we want in the air that we breathe. Breathing ozone can cause you a variety of symptoms, including coughing, chest pain, irritation of the throat, and breathing difficulty (dyspnea), due to inflammation of the airway. Furthermore, ozone can worsen lung function in people who suffer from obstructive pulmonary disease, such as asthma and emphysema.

Carbon monoxide (CO), which we have discussed in the context of pregnancy , is another air quality factor. Resulting from the incomplete combustion of organic matter, CO enters the blood and essentially hijacks the hemoglobin molecules that your red blood cells (RBCs) use to transport molecular oxygen (O2) to your body tissues and to the placenta, where the O2 is transferred to fetal RBCs. People who suffer from mild CO poisoning can be treated with 100 O2 percent through a mask, but more severe cases require hyperbaric O2 treatment, in which you are put into a special chamber, breathing pure O2 through a mask or hood most of the time that you are inside.

Another factor is sulfur dioxide (SO2), a chemical compound that can cause respiratory problems similar to those caused by ozone, plus the SO2 interacts with other chemicals in the air to produce particles that increase the amount of particulate matter. Additionally, as the concentration increases, this indicates an increase in the concentrations of other chemical compounds consisting of sulfur and oxygen atoms, which also have negative health effects.

The other major factor influencing air quality is nitrogen dioxide (NO2). This chemical causes and exacerbates a range of respiratory effects, such as airway inflammation, causing symptoms, such as coughing, wheezing, and throat irritation. Thus, as with the other chemicals, NO2 exacerbates the respiratory conditions that we have discussed above, plus it also is associated with increased number of heart-related deaths.

If you are in a region that is not being evacuated, the best thing that you can do to protect yourself and your fetus is to check the AQI of your location each day. If the AQI is above 150, then minimize your exposure to the poor quality air by staying indoors and, if possible, breathing filtered air. Keep windows and doors closed and, if your home has an air conditioning system with an option for recirculating inside air, then run it, and make sure that your filters are good. Do not pump outside air into your home, unless in runs through filters. Whether you are pregnant or not, exercise is counterproductive when you are breathing bad air. Don’t go out jogging or walking; doing so increases the volume of bad air that moves through your respiratory system in a given amount of time.

If you drive anywhere, run your car air conditioning on recirculate, not on the option for outside air. If you go outside for any reason, even to move between your house and car, a regular surgical or cloth mask –the kind you wear in public on account of COVID-19—will not protect you from the bad air, but for that minute to get from the car and get the air conditioning on and recirculating, it may help a little to hold the mask tightly around your nose and mouth, keeping air from entering from the sides. In contrast, a respirator mask, such as an N95, can offer very good protection against the polluted air, but only if you wear it CORRECTLY. This means that the N95 must fit snugly against your face, not allowing any air in from around the edges. Otherwise, it is useless. Keep in mind that there are different types of N95 masks. Some of them have a valve designed to make breathing easier by opening as you exhale, meaning what you exhale can get out without being filtered. When you go out to a public place, such as the supermarket to shop for essentials, Wearing an N95 with an exhalation filter does not negate your responsibility to wear a cloth face covering, or a surgical mask. You must cover such respirators with a surgical mask or a cloth mask to protect others from YOU. Similarly, if you see others approaching you wearing a valved respirator only, it is as if those people were mask-less. Now, if you have the type of N95 that does not have a valve, but just mask material all the way around, experts believe that the protection is good in both directions. However, since these respirators are in short supply, it is advisable to cover it with a disposable surgical mask, or a washable cloth mask anyway. Such a covering will increase the lifetime of the N95 and keep spit particles from others off of its surface.

Businesses should be requiring workers and consumers to cover valved respirators with surgical masks, but in practice, sadly, they do not make distinctions between different mask types nor how they are worn. Probably, many store managers do not even know how an what to check, so if you see a problem, point it out to a manager.

Incorrect respirator usage that I have observed around were I live include the following:

  • Various shoppers in the supermarket wearing only a valved 95, sometimes correctly, and sometimes not. I have also seen a fast food worker wearing a fancier with at least two valves, but handing loosely on her face, thus defeating the purpose. Keep in mind that N95 or other respirator worn loosely on your face does nothing for you. An N95 that fits you and is worn correctly will help you against polluted air and against COVID-19, but kind with exhalation valves won’t keep you from infecting others. Even worse, since many consumers do not realize this, the use of valved N95s as a substitute for cloth or surgical masks on public places actually has the potential to worsen the spread of COVID-19.
  • Many people in the supermarket and workers congregating in groups outside wearing masks below their noses, too loose, or down on their chins.
  • The barista at the Starbucks drive-through window wearing an N95 plus a surgical mask, but with the N95 on top! While obviously trying to do the right thing by wearing the two masks together, this very nice barista was not actually filtering anything out of the air that she was breathing into her airways and lungs, so it was as if she were wearing the surgical mask by itself.
  • People removing their masks in order to talk or to sneeze. Don’t do this.

For pregnant women in any region currently affected by the wildfires, the CDC recommends the following (quoted directly from the CDC website):

  • Pay attention to air quality reports. Follow instructions about exercise and going outside for “sensitive individuals.”
  • Follow your healthcare provider’s advice. Continue with your pre-natal care. Update your delivery plan if you need to evacuate.
  • Know the signs of labor and pre-term labor. If you have the signs, call your healthcare provider or 9-1-1, or go to the hospital right away if it is safe to travel.
  • Think about evacuating if you have trouble breathing or other symptoms that do not get better.
  • If you go to a shelter, make sure officials know that you are pregnant.
  • After a wildfire: Do not return home until you are told it is safe to do so. Smoke can stay in the air inside buildings and outdoors for days after wildfires have ended so continue to check local air quality. Protect yourself from ash. Avoid direct contact with ash and wash it off your skin or mouth and rinse it out of your eyes as soon as you can.
David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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