Canadian wildfire smoke’s return to the Baltimore region Thursday has caused air quality to reach unhealthy levels again, according to forecasters.

The Maryland Department of the Environment issued a Code Red air quality alert Thursday for the entire state, raised from a Code Orange the day before. The elevated alert warns that the air quality could cause more serious health problems for sensitive groups — including children, the elderly, and people living with asthma, heart disease or other lung diseases — and the general public may also experience some health effects.

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Meteorologist Austin Mansfield on Wednesday recommended individuals take safety precautions — and continue to monitor levels wherever they are located.

“It’s certainly something to keep an eye on,” Mansfield said.

What’s causing the smoke?

Canadian wildfire season has generated an unprecedented amount of smoke this year along northeastern parts of the United States, with 487 wildfires actively underway in Canada this week.

Midwestern states are currently facing the dangerously high Air Quality Index numbers that were experienced on the East Coast in early June. Maryland environmental officials don’t expect to see those extreme figures again here even with the northwesterly wind shift that has carried in a hazy mix of gases and fine particles from wildfires around Quebec. The northeastern jurisdiction currently has 115 active wildfires — more than any other province in Canada.

Research suggests climate change has been a main driver of recent fire weather in parts of the United States. Changes in climate are associated with warmer, drier conditions that can lead to longer and more active fire seasons.

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What impact do the fires have on Baltimore air quality?

Smoke continued to push into the region Thursday and, coupled with warm temperatures and plentiful sunshine, may contribute to elevated ozone levels.

Those levels have reached “red” on the Air Quality Index, which signifies the air is unhealthy, and not just for sensitive groups. That level still falls below the “very unhealthy” and “hazardous” readings of air pollution seen in the region earlier this month, Mansfield said.

By Friday, smoke in the area is expected to gradually push north and dissipate. Officials say afternoon showers and thunderstorms may help scour out some smoke as well.

Is it safe to go outside?

For most people, yes, though it is recommended that you reduce your exposure to the smoky air when possible.

Baltimore City health officials have previously recommended wearing masks to minimize negative health effects associated with air pollution, as well as reducing strenuous activity and exercise and shortening the amount of time spent outdoors.

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Officials recommend exercising particular caution this week for children, the elderly and people living with certain health conditions that may affect their breathing or circulatory functions.

Individuals may monitor air quality forecasts in their region on the website.