Air quality in the Treasure Valley dropped back into the Red category Thursday, signifying air that is still considered "unhealthy" due to the smoke pouring into the area from wildfires around the region.

The category is an improvement from Wednesday, when air quality plunged into the "very unhealthy" Purple category.

Unhealthy smoke levels are expected to continue into Friday.

The Idaho Department of Environmental Quality reports on its website that the air quality index (AQI) is more than 182. The AQI represents the expected level of pollution for the area. It is the average for the entire day. There may be some periods throughout the day when air quality is greater or less than the forecasted AQI.

DEQ officials issued a statewide air quality advisory in effect through Thursday at 10 a.m. at which time conditions will be evaluated again on a county‑by‑county basis. Air quality is in the moderate to very unhealthy categories throughout most of the state and is forecast to remain that way for the next 24 to 48 hours.

The forecast is calling for temperatures in Boise to reach into the 90's for the rest of the week. The AQI is expected to stay in the Red (unhealthy) range through Friday.

The following groups should avoid prolonged or heavy exertion: people with heart or lung disease, children and older adults. Everyone else is advised to reduce their activity until the air quality improves.

All outdoor recess and outdoor after-school activities and sports are canceled in Boise, West Ada, and Nampa school districts. Some practices may be moved indoors, where possible.

Parents are advised to check with their local school districts for possible changes to your child’s activity schedule.

Several large wildfires burning in Idaho, Montana and British Columbia since last week triggered the advisories. According to the National Weather Service, the wind is pushing smoke from three different directions and exasperating the problem.

Forecasters expect the smoke to stay for several days.

A reminder to those who live in Ada County and incorporated cities in Canyon County, all open outdoor burning is prohibited when the AQI reaches 60 or above. Outdoor burning is also prohibited in unincorporated areas of Canyon County when the AQI reaches 75 or above.

Indoor/wood burning is restricted when the AQI reaches 74 or above.

For information about local burn restrictions contact your local city/county office.

The Idaho Department of Lands reminds the public that we are in a closed fire season, meaning if you live outside city limits and plan to burn for any reason, you must obtain a fire safety burn permit. The closed fire season extends from May 10 to October 20.