U.S. Air Quality

Good Air Quality Today; PM2.5 Concentrations Rising into Moderate Range Tomorrow across Mid-Atlantic, Southeast, and Great Lakes

Air quality conditions were almost uniformly Code Green (Good) across the U.S. today, as shown by the loop of preliminary PM2.5 AQI values (below on upper left). There were a few isolated Code Yellow (Moderate) readings, but nothing approaching the Code Red or Code Purple incidents reported by Patricia yesterday. Fire activity is also very quiet; the National Interagency Fire Center reports that there are no uncontained large wildfires in the U.S. Today's MODIS aerosol optical depth (AOD) from NOAA IDEA indicates very high AOD values in west Texas (below on lower left), but these are false positives from the outer cloudbands of Tropical Storm Rick. It's too late in the day for a visible satellite image, but the GOES IR image of the Southeastern U.S. (below on lower right in Google Earth, courtesy of NWS) shows the current location of Rick's eye (red colors just south of the tip of Baja California) and the extent of the outer bands stretching into Texas (blue and green colors).

The Eastern U.S. is under the influence of a strong high pressure system, shown in the image below on the left (overlaid with today's Terra MODIS true color and AQI values). This high pressure is system is the reason why most of the Mid-Atlantic, Southeast, and lower Midwest experienced good air quality today. As the center of high pressure slowly moves to the east on Wednesday, light winds and rising humidity will cause PM2.5 concentrations to rise into the Moderate range. In Philadelphia, PM2.5 is forecasted to reach the upper Moderate range, which will be its highest concentration since late summer. The nationwide air quality forecasts for Wednesday are shown below on the right, courtesy of AIRNow.