The air quality west of the Cascades from Vancouver, British Columbia, south to Eugene, Oregon, has deteriorated again as wildfires continue to burn.

The Puget Sound Clean Air Agency sent out an alert Tuesday afternoon saying the smoke around Seattle was causing unhealthy air and that people should close windows and limit time outdoors. Other areas around Puget Sound were experiencing air considered unhealthy for sensitive groups or worse, the agency said.

The Portland, Oregon, metropolitan area was seeing polluted air in the unhealthy to unhealthy for sensitive groups range, according to Washington and Oregon monitoring sites. The cities of Eugene and Springfield, Oregon, were experiencing similarly polluted air.

WASHINGTON TOWN EVACUATES DUE TO GROWING WILDFIRE

The smoke-laden air gave the Pacific Northwest the designation of worst air quality in the U.S. on Tuesday, KGW Meteorologist Joe Raineri said.

Stanley Park and Lions Gate Bridge smog

Stanley Park and Lions Gate Bridge are covered in smog from clouds and smoke due to forest fires in Washington, Oregon and California on Sept. 17, 2020. (DON MACKINNON/AFP via Getty Images)

Nine fires were burning in Washington and Oregon before a red flag warning for critical fire conditions was issued over the weekend. Some new fires started while the Nakia Creek Fire in southwest Washington took off, causing much of the smoky air seen around southwest Washington and Portland, officials said.

WASHINGTON WILDFIRE EVACUATION ZONE SHRINKS, SOME ROADS REOPEN

Exposure to wildfire smoke is associated with eye and respiratory tract irritation, bronchitis, heart failure, and even premature death, according to the U.S. Environmental Protection Agency.

In the Pacific Northwest, relief should come Friday.

CLICK HERE TO GET THE FOX NEWS APP

"Friday through Saturday will be cooler and more seasonable and we’ll finally get that rain. I think everyone’s excited about that," National Weather Service meteorologist Kayla Mazurkiewicz told The Seattle Times. "We should have had a couple of inches by now."