September 21, 2007
Clear day
It was still clear today. The boundary layer extended from ~0.5km(14:00UTC) to ~1.5km(20:00UTC). The hourly PM 2.5 concentrations in the range of 8.1 to 19.2 ug/m3 were recorded at the Oldtown site during ELF’s operation. The aerosol optical depth was ~0.15 from the AERONET site, MD Science Center.
