Smoke from the Canadian wildfires will be visible in the Philadelphia region on Tuesday, but no major impacts on air quality are expected.

Over 100 "out of control" fires are burning across Canada, in particular the provinces of British Columbia, Saskatchewan and Manitoba, which sit to the north of midwest and mountain states including Montana, North Dakota and Minnesota. The Canadian Interagency Fire Center says there are 10 new fires as of Tuesday morning.

In the U.S., smoke has particularly impacted air quality in Michigan, Wisconsin and Minnesota. In Minneapolis and St. Paul, an air quality alert was in effect for forecasted "unhealthy" air, while in other parts of the state, air quality was predicted to reach the "hazardous" level.

Winds are carrying some of that smoke to the eastern U.S. on Tuesday. Smoke in the Philadelphia area will mostly stay high in the atmosphere, and the air we breathe down on the ground should stay relatively clear. No air quality alerts are in effect at this time.

The haze will start to appear Tuesday afternoon and you will probably notice the difference compared to a perfectly clear day — but the sun should still be visible.

Remember that even if it seems a little less sunny than a clear day, the sun's UV rays can still make it to the surface. You should still use sun protection as normal if you're outdoors.

This is a far different situation compared to 2023, when smoke from fires burning in Quebec descended down to the surface, greatly impacting air quality across the East Coast — and at one point, giving Philadelphia the worst air quality in the world.  

This map from our morning newscasts shows the thickest smoke, represented by the redddish orange color, setting in around 4 p.m. or 5 p.m. before cycling out overnight. Areas like the Jersey Shore could see some lingering thicker smoke Wednesday morning, which might make for a brilliant sunrise.

When air quality turns hazardous, local health authorities will issue alerts — typically the worst these get is a Code Orange, meaning the air is unhealthy for sensitive groups, like people with lung conditions.

The air quality index ranges from green for good to maroon for hazardous. You can see the full scale in the image above.

If an air quality alert is issued for smoke, it means the air contains a higher-than-normal measured concentration of particulate matter less than 2.5 microns, commonly abbreviated as PM2.5. PM2.5 is narrower in diameter than a human hair and due to its small size, can penetrate into the deepest parts of your lungs, with potential to induce inflammation or tissue damage.

As of Tuesday morning, June 3, there are no air quality alerts in the Philadelphia region including Pennsylvania, New Jersey and Delaware.

You can see real-time air conditions on a map at Airnow.gov.