More smoke is expected to drift over Iowa this week. Here’s what to know:

More smoke from the Canadian wildfires is expected to drift over Iowa this week, causing hazy skies and impacting air quality across the state.

Here’s what Iowans need to know to prepare and keep themselves safe:

Favorable wind patterns make smoke less likely to linger

Alexis Jimenez, a meteorologist for the National Weather Service in Des Moines, said “high-level smoke” is expected over most of the state beginning on Wednesday.

The smoke is coming from wildfires in Canada, which have been impacting air quality across the United States, including Iowa, over the past month.

There’s a possibility the smoke could linger throughout the rest of the week, though Jimenez said weather patterns are favorable for it to dissipate more quickly.

“There’s less of a chance of more smoke coming in when we have winds out of the south,” Jimenez said.

Air quality exceeding healthy levels at ‘unusual’ frequency since mid-May

Smoke from the Canadian wildfires has impacted air quality across the country over the past month, threatening severe health problems for millions of Americans.

As smoke makes its way through Iowa Thursday, Brian Hutchins from the Iowa Department of Natural Resources’ Air Quality Staff said AirNow, an air quality tracking system run by the federal government, predicts air quality across Iowa will be moderate. This means air quality on Thursday is not expected to exceed ozone standards, though it could still pose health hazards to those who are extremely sensitive to ozone in the air. However, Hutchins warned that air quality indexes can change rapidly as weather patterns change.

More: How bad is breathing in wildfire smoke? Graphics show how toxic air affects your health

The expected smoke is part of a growing trend of potential air quality hazards Hutchins has observed across Iowa since the start of the year, and especially since wildfires in Canada began in May. Since May 18, Hutchins said Iowa has had “68 exceedances of the ozone standard, and that is very unusual for Iowa.”

An exceedance of the ozone standard means that the air is potentially hazardous for those in sensitive groups, including children, pregnant women, older adults and people with lung and heart conditions.

What are potential health impacts of wildfire smoke?

Smoke from wildfires is different from other sources. That’s because of the unhealthy matter it contains, how it can travel long distances and persist in the air, changing over time and getting more toxic.

Wildfire smoke contains noxious or poisonous gases and particulate matter, tiny particles that can be inhaled. Those particles can penetrate deep into the lungs and affect people with respiratory problems.

More: Human activity caused the majority of Canadian wildfires sending smoke down the east coast

How can you protect yourself from smoke particles?

Hutchins recommends Iowans stay up-to-date on air quality throughout the week by visiting AirNow. If air quality reaches potentially hazardous levels, Hutchins recommends people in sensitive groups reduce outdoor activities.

To reduce harm from poor air quality, Iowans can also close windows and doors, run their air conditioners on recirculate with a new filter, wear an N95 or KN95 mask, and reduce activities that increase indoor air pollution, such as vacuuming.

Information from USA Today was used in this article.

Francesca Block is a breaking news reporter at the Des Moines Register. Reach her at FBlock@registermedia.com or on Twitter at@francescablock3.