Mark Ruminski from NOAA's Hazard Mapping System Fire and Smoke Product brought to our attention a feature that they have been observing for several days in Alaska. The GOES-15 animation (loop is about 5 hours) and MODIS Aqua "true color/rgb" image shows blowing glacial flour dust coming off the Copper River Valley extending over 250 km (160 miles) off the coast to the south. Glacial flour consists of fine-grained (silt-sized particles of rock) formed during glacial migration, where the glacier grinds against the sides and bottom of the rock beneath it. For specifics on these phenomena and its environmental implications we recommend a publication titled: "Glacial flour dust storms in the Gulf of Alaska: Hydrologic and meteorological controls and their importance as a source of bioavailable iron" by Crusius et al.
Ozone concentrations were good throughout the nation, but this was not the case for PM2.5. Moderate (Code Yellow) PM2.5 AQI levels were reported along the Mid-Atlantic and Great Lakes states, as shown in EPA's Airnow animation. A strong high pressure system limited vertical mixing, caused light winds and transported southerly humid air masses that favored the production of particle pollution. Hazy skies prevailed throughout today's lidar observations at UMBC, as a strong inversion confined pollutants near the surface, as seen by the intense scattering near the surface. The boundary layer extended to 2 km.