Air quality improving but still poses a health risk

PHILADELPHIA (AP/KYW Newsradio) — Smoke carried on the wind from intense Canadian wildfires blanketed the northeastern U.S. in a dystopian haze, turning the air acrid and the sky yellowish gray, and prompting warnings for vulnerable populations to stay inside.

The effects of hundreds of wildfires burning across the western provinces to Quebec could be felt as far away as Washington, D.C., and parts of the Midwest, blotting out skylines and irritating throats.

In Philadelphia, an air quality alert remains in effect across the city. Conditions are considered "unhealthy" — a welcome downgrade from "hazardous" — and the city said all operations will resume as usual on Friday.

Many people in the region are continuing to limit their time spent outdoors, heeding warnings from health officials about avoiding unnecessary exposure to particulate matter in the air.

Philadelphia Health Commissioner Dr. Cheryl Bettigole said the fine particles can penetrate deeply into fragile lung tissue, causing symptoms like cough, shortness of breath and wheezing. Sensitive groups of people are especially at risk, including children, older adults, people who are pregnant, or people with respiratory diseases or heart conditions.

“Keep windows and doors closed to minimize air pollution in your home. Recirculate the air in your home with fans to avoid bringing more air pollution into your home. Pay attention to how you are feeling. If you are having trouble breathing, feeling noxious or dizzy, you should seek medical attention as soon as possible," Bettigole said.

The conditions have been affecting other parts of Pennsylvania, New Jersey and Delaware, according to AirNow.gov. Find out if your region is affected here.

Smoke from Canada’s wildfires has been moving into the United States since last month. The most recent fires near Quebec have been burning for several days.

More than 400 blazes burning across Canada have left 20,000 people displaced. The U.S. has sent more than 600 firefighters and equipment to Canada. Other countries are also helping.

The smoke and haze is expected to dissipate slowly into the weekend.

After two days of limiting outdoor playtime and activities playtime, the School District of Philadelphia opted on Thursday to finish out the week by shifting to virtual learning on Friday.

In a statement posted to its website, the district said that, because there was no reason to believe Philadelphia's air quality would rise above the "Code Red" zone for the remainder of the week, out of an abundance of caution, schools would operate remotely.

"Students should prepare to log in for remote learning," the statement read. "All employees – including school-based and Central Office staff – should report to your normal work location. All school-related outdoor activities that were scheduled for [Friday], such as field trips or field days, will be postponed and rescheduled, or canceled."

In addition, according to the statement, all absences related to air quality will be excused.

Elementary school move-up ceremonies and middle and high school graduation ceremonies scheduled for Friday will proceed as planned if they are indoors. Any such outdoor celebrations will take place in new locations and potentially at different times. Individual schools will provide updates to families.

Air quality alerts are triggered by a number of factors, including the detection of fine-particle pollution — known as PM 2.5. Exposure to elevated fine-particle pollution levels can affect the lungs and heart.

“We have defenses in our upper airway to trap larger particles and prevent them from getting down into the lungs. These are sort of the right size to get past those defenses,” said Dr. David Hill, a pulmonologist in Waterbury, Connecticut, and a member of the American Lung Association’s national board of directors.

“When those particles get down into the respiratory space, they cause the body to have an inflammatory reaction to them.”

Dr. Jamie Garfield, a professor of thoracic medicine and surgery at the Temple Lung Center, said a number of her patients have told her that it's harder to breathe. "They are feeling tightness, they are feeling more congestion," she said.

There is a risk of cardiovascular events, including heart attacks and strokes, she explained.

"These particulate matter particles are so small, they are like 1/30 the size of a human hair, and they can get deposited way down in the sort of air sacs of the lungs, and they can cross right through into the capillaries so the impact is not just something that is on the lungs, the lung area and the lung tissue, but it has profound cardiovascular effects, causing the hardening of the arteries and calcium deposition."

Of people in sensitive groups, children — who often are encouraged to go out and play — are more susceptible to the smoke for a number of reasons.

“Their lungs are still developing,” said Laura Kate Bender, a Lung Association national assistant vice president. “They breathe in more air per unit of body weight.”

The scale of particulate matter in the air ranges from zero to 500. The higher the number, the worse the air quality.

Dr. Ezra Wood is an atmospheric chemist. He’s also a Drexel University professor of chemistry. He explains a little more about this measure:

“There's a bunch of things in Smoke among them lots of particulate matter. So small little particles, aerosol particles suspended in the air. And so one way measuring them is this what's the total mass within a certain volume. So you measure that and micrograms per cubic meter of air.”

Wood explains that these particles in the air are what cause the city skyline to look hazy:

“This has to do with the optical properties of these small particles. If you shine light from point A to point B, and there's particles in between that are going to scatter or absorb some of that light, then that's going to affect the visibility. If you look across the horizon, if you see City Hall from far away, you're seeing light which has reflected off City Hall and it's coming towards your eyes. So if that light coming towards your eyes now gets scattered away from you buy all those tiny particles in the air, you're not going to be able to see City Hall very well.”

And he says this scattering of light is also what causes those unusual or brilliant colors in the sky, like a pink sun against an orange background. That look is caused by pollution.

Climate scientists have predicted extreme weather events, including hazardous air quality from forest fires that happen as a result of rising global temperatures.

Climate change refers to the long term shifts in weather patterns. This is the realm of expertise of Dr. Samantha Chapman. She’s an ecosystem biologist and professor of biology at Villanova University. She's been studying climate change for more than a decade.

Chapman says global temperatures have risen 1.2 degrees Celsius since industrialization due to the emission of heat trapping gasses:

"The sea levels are higher because thermal expansion is happening to the water. The forests can be drier because there's not as much rain because the rain patterns have shifted. The floods can be more intense because there's more water in the ocean or in the rainstorms which then enter into systems."

Now globally, the goal is to reverse course, so that the temperature doesn't increase beyond 1.5 or two degrees Celsius. She says there are still a few years before we hit a tipping point. But as temperatures rise, she says weather events will continue to get more extreme.

Dr. Chapman says what’s been fascinating in her career is that scientists like herself have been predicting these kinds of extreme weather events we’re seeing now.

"I think what's been crazy over the course of my career is, I've been in the time where we knew that, started studying it, and now we're actually seeing those effects take hold in the Earth's system. And so that's been a pretty crazy ride."

“Now I think that we should get used to things that we haven't seen before. So an example in the Philadelphia area is when we had the large floods that flooded 676. That was an extreme rain event. This is an extreme drought event that's causing more fires. So yes, the extremes in our climate system are likely to be more common.”

Counselor Mark Sigmund from Retreat Behavioral Health says the anxiety stems from the story we tell ourselves about the world.

"Really what's going on is what we call a cognitive distortion. Basically, somebody is doing what we call 'catastrophizing.' And that's when you blow it up in your head and you think the worst possible outcome."

He says. though, that being concerned about the worst possible outcome is kind of understandable, right now.

"People have just gone through this huge traumatizing event of getting through a pandemic, and they start to kind of associate the two."

So how does he watch the issue?

"We spend a lot of time talking about the old saying 'One day at a time,' you know, present-centeredness. It's not always easy to do, but it's trying to use your senses to ground yourself in the moment."

And while Sigmund says it is true that the air quality is preventing people from safely going outside right now, he reminds people that that won't always be the case.

The Associated Press contributed to this report.