Likely due to wild fires all along the inner coast on both sides of the border:
https://firms.modaps.eosdis.nasa.gov/map/#d:24hrs;@-121.6,48.5,7.5z
Try to reduce time spent outside and wear a K/N95 or P100 mask if you do.
Look into purchasing (or making) an active air filtration system for your home:
*The linked service (Windy) adheres to the WHO’s AQI standards which more heavily weigh levels of PM2.5 (particulate matter 20 times smaller than a human hair) and I only post these because the government, nor any of the news services, report this at all.
¯\_(ツ)_/¯
Interesting. Would you have a source handy that I could check out? Thanks.