September 15, 2009
Another Quiet Air Quality Day
Today was another relatively quiet air quality day for our nation. Code Yellow (Moderate) PM2.5 conditions persisted in the Midwest, and air quality was Code Green (Good) elsewhere, as shown in today's loop of PM2.5 AQI values (below).
Fire activity also remains quiet across the nation. The National Interagency Fire Center reports that the Station fire in Los Angeles is 87% contained; there are several other relatively small wildfires burning in Idaho, Montana, New Mexico, and Oregon. NOAA's Hazard Mapping System reports a large area of remnant smoke and haze stretching across the North-Central U.S. into the Great Lakes, as shown below. This area of smoke may be impacting surface air quality, as current PM2.5 levels across this region are in the Code Yellow range. The advance of a back-door cold front descending north-to-south from Canada is also likely contributing to the slightly elevated PM2.5 concentrations.
There is an area of haze off the east coast of New Jersey and the Delmarva that is visible in the MODIS Aqua true color image (below on left, overlaid with AQI values and the synoptic analysis in Google Earth) and AOD image (below on right). This haze does not seem to be affecting surface air quality, which is being dominated by the advancing backdoor cold front, indicated by the blue line cutting across New England, New York, Pennsylvania, Ohio, and Michigan in the true color/AQI image.
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