Amna: Hundreds of wildfires
continue to burn across Canada,
many of them out of control.
Geoff: The smoke has more than
55 million Americans under air
quality alerts, prompting safety
warnings to stay indoors, and
the cancellation of some major
events, including professional
baseball and basketball games.
Stephanie sy has our report.
Stephanie: An ominous Orange
haze envelops the statue of
liberty.
Wildfire smoke from Canada has
billowed across the border,
degrading air quality across the
northeast and upper midwest.
Pilots and passengers flew
through thick clouds of black
smoke before the FAA temporarily
grounded flights out of new
York.
>> It's very unexpected, like it
really happened out of the blue.
And I just really hope that
everyone stays safe, you know,
wear a mask outside so the smoke
doesn't go into the lungs.
Stephanie: Today, the big apple
ranked worst in the world for
its air quality.
New York City mayor Eric Adams
issued health advisories for all
five boroughs.
>> This is an unprecedented
event in our city and new
yorkers must take precaution.
Stephanie: As wildfire smoke
continues to blanket the U.S.,
100 million Americans are under
air quality alerts.
The potential health threat
posed by wildfire smoke spanning
as far south as Georgia and
Texas.
>> The high levels of air
pollution are going to be
detrimental to people who are at
risk.
But really, everyone is impacted
by this.
Stephanie: Peter Decarlo is an
associate professor of
environmental health and
engineering at Johns Hopkins
university.
>> Exposure to air pollutants
isn't something you can undo.
These are particles that are
about 100 times smaller than the
width of our hair.
When we breathe those in and
they get into our lungs, they
can basically travel to all
parts of our body.
And so we usually think of the
respiratory system as the most
impacted.
But this also impacts our heart,
it can impact our brain.
Stephanie: In Canada, more than
20,000 Canadians can't go home,
still under evacuation orders as
firefighters struggle to contain
hundreds of wildfires.
>> Fortunate enough to have a
trailer right now that we could
get out for the time being.
Stephanie: In British Columbia,
this crew is fighting fire with
fire, burning out fuel ahead of
an approaching blaze.
Canada's minister of public
safety says there are 414 active
fires across the country, 239
are out of control.
>> I want to assure Canadians
that all orders of government
are working closely together
including with our indigenous
partners to ensure a coordinated
and effective response.
It's all hands on deck and it's
around the clock.
Stephanie: Coast-to-coast,
forest fires have scorched more
than 9.1 million acres in Canada
already this year, an area
bigger than the state of
Maryland, and it's just the
start of what is on track to be
the most devastating fire season
in Canada's history.
>> The fact that we're seeing so
many fires burning such large
areas and burning this early in
the season is definitely
worrisome
Stephanie: Climate scientist
Kristina Dahl says several
factors at play.
>> We know that climate change
isn't the only factor that's at
play in driving worsening
wildfires around the world.
We know that things like
suppressing fires for many
decades or even a century can
cause a lot of undergrowth in
our forests to build up that
would have been naturally
cleared by naturally occurring
fires and low severity fires.
But now that we have been
suppressing those fires, we have
a lot of overgrowth.
And that's causing fires to burn
larger and more severely.
Stephanie: As firefighters try
to contain the fires across
Canada, officials in many U.S.
Cities warn air quality is at
code red.
It is not the highest alert
level, but it does mean the air
may be unhealthy for some, and
outdoor activity is discouraged.
For the "Pbs newshour," I'm
Stephanie sy.