Improved PM2.5 concentrations were observed today in the Midwest and Northeast. PM2.5 concentrations stayed mostly within moderate levels in those regions, in contrast to the unhealthy levels for sensitive groups observed yesterday. Moderate levels were also observed today in the South and also in the West Coast as can be seen in today's AIRNow animation (top, left).
According to the NRL NAAPS aerosol model, the conditions observed in the East Coast and in the South were most likely due to sulfate aerosols (top, right). In the South/Southeast regions some fires were also observed. Some smoke and haziness could be observed over that region in the MODIS Aqua RGB image today (bottom, right).