Tonight on PBS News Weekend, smoke from raging Canadian wildfires drifts into the United States,

triggering air quality warnings across the Upper Midwest.

Then how lawmakers across the country are trying to rein in citizen-led ballot initiatives.

And we follow a group of rehabilitated seals making their way back into the sea off the coast of Rhode Island.

It's so important to protect the species because prior to the 1970s, the populations were almost completely decimated.

Music of the 1970s, the populations were almost completely decimated. Good evening. I'm John Yang.

Poor air quality warnings have been posted in the Upper Midwest, advising people

with heart or lung disease, older adults, and pregnant people to limit outdoor activities.

The reason is wildfires burning in western Canada, some of them hundreds of miles away.

Meteorologists say that this weekend, the smoke and the fine particulate matter it carries

could reach Oklahoma, Tennessee, and Arkansas.

Chris Fultz is a National Weather Service Central Region Fire Weather Program Manager.

The smoke is being lofted into the air, and with the weather pattern that's in place right now,

we've got an area of low pressure, basically just east of Hudson Bay

over the Great Lakes, which is bringing that air south. We also have a ridge of high pressure

over the western U.S., which is kind of helping to funnel that smoke from Canada down through

the northern plains and into the Middle Mississippi Valley. Earlier, I spoke with Matthew Capucci,

meteorologist at My Radar.

I asked him about the health risks from the smoke.

Well, there are two things I think folks are most likely noticing.

Number one, anytime you have this fine particular matter, we call PM2.5 down at ground level,

that's dangerous for elderly vulnerable populations.

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