U.S. Air Quality

Code Orange Skies over UMBC

Hazy skies prevailed today over Baltimore. The boundary layer rose from 0.5 and extended to 1.8 km during today's observations. Yesterday's residual layer mixed with today's boundary layer during the first 4 hours of operation (aerosol aloft from heights above 0.5 km up to 2.4 km). Warm air moving in from the west limited vertical mixing increasing the ground PM2.5 concentrations up to Code Orange levels. The PM2.5 concentrations at Maryland Department of the Environment Oldtown monitoring station ranged between 22-45 ug/m3 (Moderate-Unhealthy for Sensitive Groups AQI Levels: 64-100).