U.S. Air Quality

Air Quality Action Days in Baltimore

Ozone concentrations reached Unhealthy AQI levels (Code Red: 151 and 161 yesterday and today, respectively) in Baltimore, while Moderate (Code Yellow: 80) PM2.5 concentrations were recorded yesterday and Unhealthy for Sensitive Groups (Code Orange: 102) today. Nocturnal observations were carried out to support Maryland Department of the Environment Low Level Jet (LLJ) studies. No signs of LLJ activity were observed last night. The boundary layer was relatively homogeneous and extended up to 2 km.