Thick Smoke in Western Washington and Oregon to Soon Clear

SEATTLE (AP) — A haze of smoke covering parts of western Washington and Oregon is expected to clear before the week's end, but only after the region reached a dubious distinction: Seattle and Portland briefly topped a list of large cities with the worst air quality in the world.

The smoke comes from several wildfires burning in Washington and Oregon, and several days without rain allowed it to linger and thicken. A new weather pattern was expected to hit the region on Friday, according to a National Weather Service forecast, bringing multiple rounds of rain that will help scrub the air of pollutants.

On Thursday morning, Seattle was listed as the worst city in the world for air quality and pollution and Portland ranked third, according to IQAir, a company that gathers air quality information from around the world.

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.

People with asthma, heart disease or other medical issues can experience negative health effects from lower levels of air pollution. Communities near Eugene, Oregon reached “hazardous” air quality levels late Thursday morning, according to the government website AirNow, a level that means everyone is more likely to experience negative impacts.