PHILADELPHIA (WPVI) — Air quality alerts are in effect in Philadelphia and across the Delaware Valley as hazardous smoke from the Canadian wildfires hangs over the region.

A Code Red Air Quality Alert is in effect for Pennsylvania and Delaware, while New Jersey is under a Code Orange.

A Code Red means that air pollution concentrations are unhealthy for the general population and outdoor activity should be avoided. A Code Orange represents unhealthy pollution levels for sensitive groups, including children, the elderly and those suffering from asthma, heart or lung disease.

The FAA has paused flights from the Northeast, Mid-Atlantic and Ohio bound for Philadelphia International Airport due to low visibility.

Travelers were encouraged to check with their airline for the latest information.

The US Air Quality Index has Philadelphia with some of the worst air quality in the world.

Overnight, Philadelphia peaked at 427 out of a maximum of 500. As of Thursday morning, that number was down to 361, but anything over 301 is still in the Hazardous zone.

It is a sign the region is making progress in getting out of the smoke.

Experts say, however, it is a good time to put off that yard work and outdoor exercise. If you do go out, you could also consider wearing an N-95 or KN-95 mask to reduce your exposure to pollutants.

They also recommend staying inside, keeping your windows and fireplaces shut, and running the air conditioning on a recirculation setting.

“These are very, very fine particulates that can be breathed very deep into the lungs, and they can do damage to the lung,” said Philadelphia Health Commissioner Dr. Cheryl Bettigole. “It can sometimes get into your bloodstream.”

6abc Air Quality Tracker

SEE ALSO: NYC’s air pollution among world’s worst as Canada wildfire smoke shrouds Northeast

Health officials also warn residents to pay attention to their bodies. Anyone who may be having trouble breathing, feeling nauseous or dizzy, should seek medical attention as soon as possible.

“You can start feeling chest tightness. You may start coughing and may feel your eyes burning,” Bettigole said.

The U.S. Environmental Protection Agency says hazy skies, reduced visibility and the odor of burning wood are likely, and that the smoke could linger for a few days.

How long will it last?

According to AccuWeather, the smoky conditions may improve over the next several days.

Modeling shows this plume continuing to push southward with gradual improvement through Thursday.

Once the blocking breaks down and our winds shift out of the south, we will cut off that funneling of smoke into our area. That is expected to happen over the weekend.

As we get into Saturday, that block begins to ease some with low pressure exiting eastward. When this happens, we should begin to dilute the flow of particles and slowly improve air quality.

SEE ALSO: Why is smoke from Canada impacting the Philadelphia region and when will it go away?

Our next chance of a few showers comes on Friday afternoon and evening, but that doesn’t look very impressive.

Our best chance looks to be on Monday when a more impressive system could move in.

Why are we smelling the smoke?

The reason we are seeing such concentrated smoke has everything to do with the weather.

We are stuck between low pressure out east of Maine with high pressure out west of us. That means wildfire smoke is being directly funneled through the northeast and into our region.

How to protect your pets?

Experts say that fine particles of burned debris in the air can be harmful to humans and animals alike.

One of the biggest things you can do for your pets is limit their outdoor exposure while the air quality is hazardous. This means keeping pets indoors as much as possible and keeping windows and doors shut.

Cats and dogs should only be taken outside for brief bathroom breaks if air quality alerts are still in effect.

Birds are particularly susceptible to poor air quality and should not be allowed outside during hazardous conditions, experts say.

SEE ALSO: How to protect your pets as smoke from Canadian wildfires fill region

Outdoor events canceled/Schools make changes amid unhealthy air

The Philadelphia Phillies’ series finale against the Detroit Tigers on Wednesday night was postponed due to poor air quality.

The game was rescheduled for 6:05 p.m. Thursday, which was originally an off-day for both teams.

In South Jersey, Haddonfield’s Little League canceled games out of precaution; the music venue at McLaughlin Norcross Memorial Dell in Camden County was also closed Wednesday night.

Earlier in the day, the Philadelphia Department of Public Health notified organizations and area schools about planning outdoor activities.

In response, the Philadelphia School District said that students and staff would remain indoors and limit time outside. The district repeated that announcement on Thursday morning.

“At schools, outside activities such as recess, outside field trips and field days will be moved indoors if possible, postponed or canceled. The District’s Athletics Office will support schools in rescheduling outdoor athletic games that were previously scheduled. In addition, all windows and doors at school buildings will remain closed to minimize air pollution,” the Philadelphia School District said.

School crossing guards in Philadelphia will also cover their corners on a modified schedule Thursday and Friday. Hours for coverage have been reduced to permit crossing guards to cross students during the most critical times connected to both the start of the day and dismissal.

The district does not expect an early dismissal, as conditions are set to improve Thursday afternoon.

Schools in the suburbs also made changes.

Due to the hazardous air quality in Montgomery County, school officials announced Thursday that Cheltenham High School’s commencement has been postponed until Friday at 9:30 a.m.

Neshaminy School District has moved classes to online learning on Thursday.

The Black Horse Pike Regional School District in Camden County announced it will be closed Thursday due to poor indoor air quality.

Canadian officials ask for help

Canadian officials asked other countries for additional help fighting more than 400 blazes nationwide that already have displaced 20,000 people.

Canadian officials say this is shaping up to be the nation’s worst wildfire season ever. It started early on drier-than-usual ground and accelerated very quickly, exhausting firefighting resources across the country, fire and environmental officials said.

Smoke from the blazes in various parts of the country 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 – which, unsettlingly, was National Clean Air Day in Canada.

The smoke was so thick in downtown Ottawa, Canada’s capital, that office towers just across the Ottawa River were barely visible. In Toronto, Yili Ma said her hiking plans were canceled and she was forgoing restaurant patios, a beloved Canadian summer tradition.

Quebec Premier Francois Legault said the province currently has the capacity to fight about 40 fires – and the usual reinforcements from other provinces have been strained by conflagrations in Nova Scotia and elsewhere.

Canadian Interagency Forest Fire Centre spokesperson Jennifer Kamau said more than 950 firefighters and other personnel have arrived from the U.S., Australia, New Zealand and South Africa, and more are due soon.

The Associated Press contributed to the story.