Experts recommend staying inside, wearing masks as fire conditions worsen in Western Washington

The wildfires burning in Eastern Washington are sending smoke over the Cascades.

The smoke rolled in Monday night and quickly sent the air quality to unhealthy levels, according to the Puget Sound Clean Air Agency.

>> 6 tips for staying healthy during smoky air conditions

Experts recommend residents stay inside and keep their windows closed if possible. If they need to go outside, the suggest wearing a mask.

While N95 mask would normally be recommended, especially for those with pre-existing conditions like asthma, during the pandemic those masks are in short supply and needed by medical professionals. Researchers at UW say cloth masks they filter out about 50 percent of the smoke particles.

Dan Jaffe, professor of occupational chemistry at UW Bothell, tested the air quality inside and outside his Seattle home on Tuesday. He found the levels were the same.

Jaffe found if he put a furnace filter on the back of a box fan. He left the fan on to recirculate the air in his guest room.  Jaffe says the air quality improved by 90 percent.

The smoke is expected to linger in the Puget Sound for a few more days. With breezy conditions, low humidity and no rain, the fire danger is still very high. There is a Red Flag Warning in effect through Thursday for very high fire danger.