The Bay Area Just Turned Orange. All Eyes Are on PurpleAir

The Bay Area Just Turned Orange. All Eyes Are on PurpleAir

Drawing crowdsourced data from air quality sensors it sells to the public—ranging between $200 and $300—PurpleAir builds maps that show in real time just how bad a neighborhood like mine is suffering from particulate matter (PM) 2.5 pollution, the particles that make up wildfire smoke.