Smoky haze blanketing Philadelphia, northeast could last for days

PHILADELPHIA - Philadelphians awoke to a smoky sunrise for a second straight day Thursday, and the hazy conditions could linger for a few more days. 

Forecasters say that with weather systems expected to hardly budge, the smoky blanket billowing from wildfires in Quebec and Nova Scotia should persist into Thursday and possibly the weekend. 

The National Weather Service in Mount Holly shared Thursday morning that the smoke should dissipate in the Delaware Valley through the morning and afternoon before it becomes more dense this evening. 

Before any significant clearing could occur, the Federal Aviation Administration temporarily grounded flights bound for Philadelphia due to low visibility. On Twitter, airport officials urged travelers to check with their airlines for updates.

Across the eastern U.S., officials warned residents to stay inside and limit or avoid outdoor activities again Thursday, extending "Code Red" air quality alerts in some places for a third-straight day as forecasts showed winds continuing to push smoke-filled air south.

In Philadelphia, health officials issued a code red Wednesday morning for unhealthy air across the city. That alert remains in effect Thursday. 

"This alert means that the air is unhealthy to breathe, and some members of the general public may experience health effects," the Philadelphia Department of Public Health said.

Officials are urging residents to take these precautions at this time:

• Strongly consider canceling outdoor events and gatherings
• Avoid going outdoors as much as possible
• Avoid excessive activities outdoors, such as jogging or exercising
• If you have to go outdoors, wear a high quality mask, like an N-95 or KN-95 mask
• Avoid areas of high congestion and where air pollution may be high, like main streets or highways, areas with low air circulation
• Close all windows and doors 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 their bodies; if they are having trouble breathing, feeling nauseous, or dizzy, they should seek medical attention as soon as possible.

For the rest of the Delaware Valley, a code orange is still in effect Thursday, which means a concentration of these air pollutants is unhealthy for sensitive groups. 

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.

Canadian Prime Minister Justin Trudeau spoke to President Joe Biden by phone on Wednesday. Trudeau's office said he thanked Biden for his support and that both leaders "acknowledged the need to work together to address the devastating impacts of climate change."

Canadian officials say this is shaping up to be the country's worst wildfire season ever. It started early on drier-than-usual ground and accelerated quickly. Smoke from the blazes has been lapping into the U.S. since last month but intensified with recent fires in Quebec, where about 100 were considered out of control Wednesday.

In the U.S., federal officials paused some flights bound Wednesday for New York's LaGuardia Airport and slowed planes to Newark and Philadelphia because smoke was limiting visibility.

The Phillies had their game postponed due to the conditions Wednesday night as well.

What's the biggest concern?

Air quality alerts are triggered by a number of factors, including the detection of fine-particle pollution — known as "PM 2.5" — which can irritate the lungs.

"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."

Trent Ford, the state climatologist in Illinois, said the atmospheric conditions in the upper Midwest creating dry, warm weather made it possible for small particulates to travel hundreds of miles from the Canadian wildfires and linger for days.

"It’s a good example of how complex the climate system is but also how connected it is," Ford said.

Who should be careful?

Exposure to elevated fine particle pollution levels can affect the lungs and heart.

The air quality alerts caution "sensitive groups," a big category that includes children, older adults, and people with lung diseases, such as asthma and chronic obstructive pulmonary disease.

Kids, who often are encouraged to go out and play, "are more susceptible to smoke for a number of reasons," said Laura Kate Bender, the lung association's National Assistant Vice President, healthy air. "Their lungs are still developing, they breathe in more air per unit of body weight."

What can you do for now?

It's a good time to put off that yard work and outdoor exercise. If you go out, consider wearing an N95 mask to reduce your exposure to pollutants.

Stay inside, keeping your doors, windows and fireplaces shut. It's recommended that you run the air conditioning on a recirculation setting.

"If you have filters on your home HVAC system, you should make sure they’re up to date and high quality," Hill said. "Some people, particularly those with underlying lung disease, or heart disease, should consider investing in in air purifiers for their homes."

How can you keep your pets safe? 

AirnNow.gov recommends keeping pets indoors as much as possible with the windows closed. They also suggest keeping your indoor air clean by avoiding cooking methods like frying or boiling, and avoiding vacuuming or burning candles. 

Smoke can be especially tough on pet birds, so it's recommended they are kept inside.