If this week’s wildfire smoke left residents mistaking Lane County for another planet, that may be since the pollution was unmatched in modern county history.

Local air quality readings Sunday through Tuesday recorded pollution levels not seen since before 1980, when the Lane Regional Air Protection Agency began measuring the affects of fine particulate matter.

“I expect there weren’t higher days even in the late 1970s,” LRAPA Director Merlyn Hough said. To find a worse stretch of air quality in Lane County history, “I’d expect you’d have to go back to the … early 1970s, maybe the late 60s.”

LRAPA since 1980 has tracked concentrations of fine particulate matter — microscopic airborne pollutants caused by industrial pollution, wood smoke and other emissions — in the Eugene area. The agency reads particulate levels with a device called a nephelometer, which gauges the dimming effect of pollution on sunlight. Those readings yield a numerical score known as a “beta scatter” amount, with higher ratings indicating greater pollution.

Read more at the Register-Guard.