Pima County issued the following announcement on Nov. 13.
Pima County Department of Environmental Quality (PDEQ) is issuing a health watch for particulate matter. PDEQ monitors particulate matter air pollution from several sites and reports that although the Environmental Protection Agency’s 24-hour particulate matter health standard has not been exceeded at this point, wind-blown dust levels are increasing this afternoon.
Winds are forecasted to continue until Thursday, so it is possible that our skies could remain hazy until the wind calms and the dust settles out.
Until the dust has settled, those who are sensitive to particulate matter should try to stay inside with windows and doors closed to reduce their level of exposure to outside air. In addition, if you are in a dust-prone area, you may want to reduce your level of exertion if you need to be outside. PDEQ monitors two different sizes of particulate matter (PM10 and PM2.5) at several different monitoring stations.
Particulate matter that is 10 microns in diameter or smaller poses the greatest health problems because the small particles can travel deeper into the lungs.
For up-to-the-hour air quality information, visit the PDEQ website.
Original source can be found here.