out here in Northern California.

We are way too familiar, painfully familiar with the terrifying effects of wildfires.

The damage, the health concerns, it's almost impossible to ignore.

And not just here, but in many parts of the country and world.

Just take a look at what recently happened in Maui.

That was one of the worst, most devastating fire disasters ever.

And while fires are not new to Maui and are sadly familiar here in California and much of the West, this summer put fire on the radar of people who never had to really think about it.

Smoke from wildfires in Canada caused air quality alerts in cities more than a thousand miles away.

This affected more than 70 million people at the time.

And as fires get bigger and more damaging, we're only starting to get a handle on the long term health issues Here in California, fires burn basically every year, but in 2020, they've got completely out of hand.

That summer saw the largest fire in California's history, the August complex fire, which burned more than a million acres.

And it caused air quality issues in San Francisco, which is hundreds of miles away.

The sky here looked like hell, literally.

from a health perspective.

That smoke is what really does the damage like burning eyes, a sore throat, a cough.

But there are certain vulnerable populations that may have much more health impacts.

For example, someone who does have asthma, you know, is more at risk to have an asthma exacerbation when they breathe a smoke or someone with COPD, chronic obstructive pulmonary disease, is that increased for a flare up when they inhaled the smoke?

there can be increases in heart attacks, arrhythmias.

There can be increases in stroke.

when the air quality gets bad, which can happen rapidly.

In the case of a fire, we see and feel the effects almost immediately.

there's there was a study showing that when it was a accumulate in Canada, when they were exposed to the smoke within 2 hours there was increased in ambulance calls for respiratory distress and cardiac distress.

It seems that fire season is getting longer and the fires are getting worse.

But I worry, will this trend continue forever?

Is it inevitable?

We asked Miami and our friends at Weather to explain.

Is this part of a runaway train that we might call climate change?

Well, first off, climate change doesn't directly cause fires, but it does make the underlying conditions more prone to fire.

Extreme wildfires basically need three things low humidity, high wind and an ignition source.

Climate change doesn't affect wind or ignition much, but it does make dry periods drier.

So it's more likely for a wind event and an ignition like a downed power line or lightning to align with a very low humidity.

Dry day In northern Canada, there were very hot days that dried out the tundra and forests.

Then you add lightning, and when on a low humidity day over and over early in the season and you get record numbers of acres burned.

Similarly, in LA LA, we saw drought conditions combined with low humidity and extreme wind, which likely downed power lines that ignited the fire.

Interestingly, we saw even larger areas burned in the early 1930s during the hot, dry era known as the Dust Bowl.

But then we entered a cool wet period and firefighting became a lot more effective in acres burned, plummeted.

And then that's when we really expanded communities and infrastructure into wildlands that tended to see more fires.

So as we moved away from the cool wet period coupled with growing population and risky areas and the effects of climate change, wildfires had become more devastating.

So is anywhere safe from the risk of wildfires today?

well, the Midwest and Northeast stand out as less vulnerable since both are getting wetter on average with climate change.

So while they may face an increased flood risk, wildfire is lower on the list of extreme weather hazards there.

but as we saw with the smoke from the Canadian wildfires this year, I'm not sure any of us can escape the impacts entirely.

So what exactly is in smoke that makes it so harmful?

Well, obviously, it depends on what's burning, but combustion always produces pollutants.

One particularly harmful product is called particle pollution or particulate matter or PPM.

Scientists measure particle pollution by size.

For example.

PM10 particles are ten micrometers across PM 2.5 particles are 2.5 micrometers wide.

That's 40 times smaller than the smallest thing you can see with the naked eye.

By comparison, a human hair is 50 to 70 micrometers wide.

In the world of health and medicine.

You hear a lot about PM 2.5.

These very tiny particles are extra harmful because they're small enough to be absorbed into lung tissue and then passed through into the bloodstream.

the particles are so small they can be inhaled and go all the way down to the base of our lungs and then actually cross over into the bloodstream.

And once it's in our body, the particulate matter, which, you know, has other tangle along toxins on it, such as, you know, heavy metals and other things can circulate throughout our body, causing all kinds of problems.

A wildfire can also produce other dangerous pollutants, especially if it's burning up buildings, homes and everything in between.

And this produces all kinds of chemicals which then go up into the air.

On top of that wildfire, smoke, like any smoke, is full of carbon monoxide in high concentrations.

Carbon monoxide blocks your body from absorbing oxygen.

And this can lead to headaches, nausea, dizziness and even death.

one big concern is the effect of repeated exposures year after year.

Or breathing in smoke for days and days on end.

There's a lot of increased research right now, but there's a lot of things we don't know.

especially for the general population who's healthy, you know, and is now maybe experiencing a big burst of smoke for a few days once a year.

in fact, we don't really know just how bad this is.

The studies haven't been done, but we can learn something by looking at the people who are exposed to smoke routinely as part of their job.

I'm talking about firefighters.

One study found that Wilderness firefighters are at an increased risk of dying from lung cancer and cardiovascular disease.

Another study with a broader sampling of firefighters found a reduction in lung function.

There really aren't other groups that have that type of exposure.

We know that they're more at risk from certain types of cancers.

And so in studying them and especially looking at their immune system and seeing where it goes awry.

So hopefully we can start to, you know, figure out mechanistically, why is it leading to cancer and then hopefully be able to do something to prevent it.

Now, it's hard to draw a direct comparison because firefighters have much more exposure to smoke than the general public does.

But studies of firefighters do offer us a hint of what we might expect as big fires become more common.

It's easy to believe that breathing in smoke year after year might not be good for you.

some of the connections are surprising.

For example, some studies have found that smoke exposure increases risk of developing dementia.

Other studies have found a link between wildfire smoke and depression and anxiety.

But it's also true that some people are at a higher risk.

As with many things, this includes children and older adults.

Children tend to have smaller airways that clog more easily.

They also breathe in more air per body weight, which makes them more susceptible to pollution.

A especially those little babies.

wildfires can cause personal and environmental devastation.

And few places know this as well as Northern California.

Dr. Christine Wu is public health director in Napa County.

what we have seen based on our birth certificate data that shows a decline in average birth weight and a corresponding increase in preterm births in the quarter following wildfire smoke exposure for 2017 and 2018.

The peak in 2017 was the first time we saw preterm births over 10% of all births in many years.

And I thought that was really interesting and telling.

pregnant women.

That's a big category.

The mom and the baby are at risk because we know when a mom inhales wildfire smoke, depending on how much they inhale and for what duration and for where they're at in their pregnancy.

That baby could be born early or be born at a low birth weight from that smoke exposure.

But here's the good news.

You can protect yourself to a point by being prepared.

So what does that mean?

Number one, get familiar.

Very familiar with the air quality index.

This tool that was developed by the U.S. Environmental Protection Agency gives us an overall picture of air pollution at any given time in any given location.

It factors in five kinds of pollutants, including particle pollution, like we talked about earlier.

And it mashes hourly measurements into a numerical rating system.

1 to 500.

Anything under 100 is considered pretty clean air.

But the higher the number, the worse it is outside over 101.

And so this will issue an air quality alert.

And AQI of 101 250 may trigger symptoms in anyone, especially those who are sensitive and 151 or 200 is bad for just about all of us above 200 things get really dangerous.

You may need to limit the time you spend outside when the Canadian fires and smoke down the East coast This summer, the AQI in New York City went all the way up to 400.

Anyone can feel those effects immediately.

And in fact, on the worst smoke day.

Emergency room visits for asthma in the city were up more than 50%.

So it's a good idea to check the AQI, the air quality index every day.

Like you would check the weather.

You go online, you put in your zip code, and there you go.

So, for example, the AQI is high.

Consider moving activity indoors.

If you go outdoors, consider decreasing your minute ventilation, such as going for a walk instead of a jog, and consider the total duration outdoors.

You can also wear one of these things that we got so familiar with during COVID.

An N95 mask or a K and 95, essentially the same thing, but it has to be a 95 or Kane 95 surgical masks, cloth masks, bandanas.

None of those will block the tiny particles from wildfire smoke Also, let's not forget about our four legged friends.

Pets need to breathe too, so don't make them suck up pollution on a long walk while you wear a mask.

That's not fair.

Also, keep in mind that air pollution can get inside your house.

Also, if you own your home or have a good landlord, consider upgrading the air filter in your central ventilation or HVAC system.

ensure that the filter that we have in there is actually at the highest efficiency compatible with our system.

And each of these filters have what's called a MERV rating.

That's the minimum efficiency report reporting value.

And if we can get that rating to be a true high filter rating of 13 to 16, it can remove as much as 95% of the particles that pass through it and can be especially important during smoky periods.

You can also use a portable air cleaner that's designed to treat just a single room.

you might want to consider kind of creating a clean air room within the home, which it would be a place everybody could go where the air purifier could be working, and the room is kind of better sealed so that if you are exposed to the smoke, you can at least, you know, be out of it for a significant part of the time.

and we've listed more info in the show description.

So check that out That does it this week for vitals.

But this topic of wildfires and smog, unfortunately, isn't going anywhere.

So big things to Maia and a team at Weathered.

Make sure to check out their episode on how climate change is ushering in a new era of disease risk.

It's another collab between our two shows.

In the meantime, hit us up on socials at PBS vitals.

Tell us your thoughts.

Also, please check your air quality index every day, please, and thank you.