WENATCHEE — Air quality in the region rose to a "very unhealthy" level Thursday as smoke from local wildfires cast a veil over the mountains.

As of 1 p.m. Thursday, the state Department of Ecology had a reading of 204 on its air quality index for Wenatchee. Visibility was 9 miles, and wind speeds were at 1.5 mph.

"This has been the worst air quality we've seen this year," said Ecology spokesman Andrew Wineke.

However, he said it's not as bad as last year, when there were more fires burning and the poor air quality lasted for longer periods.

Wineke said the air quality should improve through the weekend, with a front expected to blow out the smoke. However, it is expected to deteriorate again by next week.

"The current smoke should be blowing out, so it depends on whether we see new fires," Wineke said. "As we get into next week, the front will have moved through and we'll get some more hot temperatures. Of course, the fires that are still burning will just be pouring that smoke into Eastern Washington again."

He said Washington has seen effects from wildfires in Oregon and California, but local fires, such as the one near Cougar Creek, are causing Wenatchee's poor air quality.

"The hot temperatures for the last week, that's a weather pattern associated with high pressure off the coast. It just means that there's not a lot of air movement through the state," he said. "That allows the smoke from those local fires — you've got a couple burning nearby there — to pile up and really lead to some poor air quality."

Wildfire smoke can cause burning eyes, sore throat, headache, coughing and shortness of breath.

Wenatchee city pool programs were canceled Wednesday and Thursday. A show planned for Friday as part of the Summer Concert Series at Centennial Park was also canceled because the performer would have been traveling from out of town.

Ecology was advising everyone to limit time outdoors, set their air-conditioning to recirculation and keep pets inside if possible. Certain groups are especially vulnerable, including those with heart or lung disease, asthma or diabetes; people who have had a stroke; children; people over 65; and pregnant women.

Ecology set up a portable air monitor in Plain on Thursday to offer more detail on the local air quality, Wineke said. Such monitors supplement the department's permanent monitoring network.

For current conditions, the latest forecast and other wildfire smoke information, visit wasmoke.blogspot.com.