Unhealthy and hazardous air will stay in Western Washington for much of this week. Air quality scientists say they are looking for wind — not rain — to clear things out.
Phil Swartzendruber, a scientist with the Puget Sound Clean Air Agency, says the small particles of unburned carbon that are making up this blanket of smoke from Oregon and California are hanging in the air. He says to think of it as a gas, not as bits of ash that fall to the ground.
Swartzendruber says that means rain won’t necessarily clear this gas out. “Because, when it's raining, the droplet falls and these tiny little particles are so small, they behave more like gases. They just kind of move all around, move out of the way,” Swartzendruber said.
Scientists say we would need substantial and sustained rain to clear the air. A light drizzle won’t do it. The hope is that winds coming from the Northwest will start to move the smoke out of the region starting Friday.
“We're going to go back to getting winds from the Northwest. That will be bringing us ocean air that hasn't had a chance to pick up any wildfire smoke," Swartzendruber said. "And that should be consistent enough. We should be able to get cleaned out for this weekend.”
Until then, Swartzendruber advises people with asthma and COPD to limit outside activity as much as possible. If you are a healthy adult and not pregnant, it’s OK to go outside for a bit: “It's OK to go out and get the mail. It's OK to take the trash out. It's OK to go get some groceries.”
But, he adds, “just don't be don't be running a marathon in this. Don't be trying to do a new time record for your 3-mile run. Take it a little easy.”