How to better understand AQI, or air quality index

AQI is the way we measure something called particulate matter 2.5 microns (PM 2.5). The reason this number is important is because PM 2.5 is “so small it can get into the very lower reaches of your lungs,” explains Dr. Nadeau. An AQI of about 30, for example, is equivalent to smoking one cigarette a day. Even though AQI doesn’t measure other pollutants in the air, and we don’t know exactly how it affects children, pregnant people, and the elderly, it’s the “best we can do right now.”

But no matter what the number is (or the color, if you’re in an area that uses a color-coding system), “if you’re outside and you’re feeling like you want to cough and the air is bothering you, get inside to a filtered room [and] put on an N95 mask,” says Dr. Nadeau. “There is no safe distance [from air pollution,] but we can change our behaviors around it.”

The long-term health effects of wildfire smoke

Studies on firefighters show that, in general, they have a life-expectancy that’s less than 10 years that of the average American. Some of these firefighters get exposed to wildfire smoke “and it affects their hearts, their cardiovascular system, increases thrombosis, and affects their inflammatory markers,” says Dr. Nadeau. It can also increase the risk of cancers and strokes, and increase blood pressure.

With more frequent wildfires, “we’ve been noticing dramatic health effects, [including] premature births and prematures deaths — about 7 million people die per year due to air pollution and wildfire smoke exposure,” says Dr. Nadeau. These numbers are not just how wildfires affect firefighters, but how they affect the public. Dr. Nadeau notes the seriousness of the situation, explaining that even smoke exposure from 100 miles away is very dangerous. “As smoke  hovers in the air, it actually turns into different chemical compounds that are even more toxic than they were days before.”

The differences between controlled burns and uncontrolled burns

“What has been shown across the world is the controlled burns really do cut down on the amount of smoke,” explains Dr. Nadeau. It clears out the brush on the bottom of the forest so that it can grow anew, decreasing the frequency of wildfires overall. “It’s healthy for the forest, and it’s not unhealthy for people to be able to be around when a controlled burn happens,” she says.

Wildfires can create their own weather patterns and create such an intense heat that the wildfire smoke is 100 times more toxic than air pollution and 10 times more toxic than smoke from a prescribed burn. A controlled burn also gives community members the opportunity to leave and get to an area where they won’t be exposed to smoke.

How to protect yourself and your children when the AQI is high

In general, if the AQI is greater than 100, you should stay inside, especially sensitive groups like children and pregnant people. “Children that are developing — anyone between five to 18 — if they’re exposed to an AQI over 100, even for eight hours, it can increase the risk of coughing, asthma, and wheezing.” And for infants and toddlers (anyone under the age of five), smoke exposure has been shown to increase asthma rates up to four-fold. “There is no study on how much time could hurt a child’s lungs, so I just want to avoid any time outdoors if the air quality index is around 100 or more,” explains Dr. Nadeau.

If you have to be outside, no matter what group you’re in, you should wear an N95 mask (without a vent). “Luckily, when you have a well-fitted N95, you will not be able to get exposed to most particles in wildfire smoke,” she says.

How best to filter the air in our homes

“Wildfire smoke, having a viral illness — all of these things for any one person could be the tipping point,” says Dr. Nadeau. That’s why having access to proper filtration is so important. Dr. Nadeau recommends using a HEPA filter with a MERV 13. Filters have different gradations, so make sure the one you’re using matches the square footage of the room or home you’re filtering. “These particles are less than the diameter of your hair,” says Dr. Nadeau. “To really get them out of the air, you need a MERV 13 or higher.” Just like the lint in your dryer, these filters are going to catch the smoke particles you don’t want in your home. 

How allergies and climate change are connected

In the past several years, Dr. Nadeau has noticed that her patients in the Bay Area are saying year-after-year that it’s the worst pollen season yet. “I would keep trying to treat them, and it would never be enough,” she says. “With climate change, with global warming temperatures happening, we are seeing an increase in seasons of pollen by two months.” For example, trees in the Bay Area used to pollinate in March. Now they start pollinating in January. “This is happening throughout the globe,” Dr. Nadeau notes.

One in three people on the planet experience allergies at some point in their life, and “allergies are only going to get worse,” she says. “We need to think of new ways to prevent, but also new ways to treat [them].”

Some new therapies she mentions include sublingual immunotherapy, nasal sprays, and biologics that can be given as shots. “A lot of other people that don’t suffer from allergies and asthma think that they are nuisance diseases,” says Dr. Nadeau. “But I would say they’re not. They are truly disabling diseases. And so if we can accommodate, mitigate, and adapt to climate change, that’s important.”

Next time, we’ll be talking about the gut-immune connection with author and physician, Dr. Emeran Mayer. Subscribe below.