Nearly half a million acres have Grayson  Prestonburned in Idaho as fires engulf national forestland across the state.

As of Saturday, more than a dozen wildfires were blazing across the mountain West state, according to the National Interagency Fire Center. Outside the state capital Boise, several fires in the Boise National Forest have burned more than 350,000 acres. Smoke has triggered local air quality indices near the fires to reach “very unhealthy” levels, according to the state Department of Environmental Quality.

Elsewhere in the state, the Red Rock fire, about 15 miles west of Salmon, a small city closer to the Montana border, has burned nearly 70,000 acres in the Salmon-Challis National Forest, according to an update Saturday. The fires, which started from a lightning strike, is currently 19% contained.

More than 600 personnel are fighting the fire, with firefighters burning areas near forest roads to prevent fuel for the fire to spread further, the update said. Dozers also are building fire lines toward the south.

About 7 miles north, the Garden Fire has burned nearly 10,000 acres with no containment.

With both fires, Loretta Benavidez, a spokesperson for the U.S. Forest Service, told USA TODAY that fire conditions will likely be “quieter” over the weekend with somewhat cooler temperatures. “We have to take it day by day,” she said.

Smoke is also playing a role in “shading,” with particulate matter creating cover that reduces the sun beating down and keeping temperatures cooler and humidity higher.

But because of this, state officials issued an air quality advisory for the region through early next week. Pollutants from the smoke can cause breathing issues for children, elderly people and those with respiratory issues, state officials said. Officials recommended that people limit prolonged or strenuous activity outdoors.