U.S. Air Quality

Goodbye Summer, Welcome Fall

A residual layer, that extended up to 1.6 km, fully mixed with today's cloud capped boundary layer around 19:30 UTC. Even though the PM2.5 AQI levels have been moderate, the PM2.5 concentrations have been decreasing during our observations. Scattering near the surface and within the boundary layer, shown in the lidar timeseries, decreased during the afternoon. After 0:00 UTC strong winds (greater than 10 m/s) from the northeast started to move over Maryland (wind profiler timeseries is shown below), providing good ventilation and a cleaner air mass between 0.5-1.3 km. Low altitude clouds (around 300 m) advected over UMBC after 3:46 UTC which led to the termination of today's observations and an increase of counts near the surface.