Good air quality was reported today by AirNow over the country. Some scattered regions reached just moderate levels in PM2.5 (top left). Ozone levels also reached Moderate levels in few areas in a very short period of time (top right). Hazard Mapping Fire and Smoke Product reported some fires in the Mississippi Valley region as well as in Canada (bottom left). Numerous agricultural fires burning across the north central US and south central Canada are producing an area of light smoke moving west-northwest into northern Minnesota, northeastern North Dakota and southern Manitoba.
According to the Fourmile Canyon Fire, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured a natural-color image of the fire at 12:15 p.m. local time (18:15 UTC) on September 6, 2010 (bottom right). The red outline corresponds with the unusually high surface temperatures associated with an active fire. A river of thick smoke flows eastward. Over the plains northeast of Denver, the smoke plume casts a shadow to the north.
This image shows the city of Boulder lying in the path of the smoke. The same day that MODIS acquired this image, Boulder County issued a public health alert warning residents to limit physical activity and remain indoors if possible. On September 7, smoke continued to affect air quality and limit visibility in Boulder. Early on the morning of September 7, news sources reported that the fire was still not contained. Today, due to clouds, no AOD retrieval is available over Colorado area.