Haze lingered in California’s San Joaquin Valley on December 16, 2007. The Moderate Resolution Imaging Spectroradiometer (MODIS) flying on NASA’s Terra satellite captured this image the same day. In this picture, gray haze fills much of the valley west of the Sierra Nevada. Sporadic clouds float overhead, and thick clouds also appear on either side of the valley. In the east, cloud cover blends with snow cover on the mountains.
A December 13, 2007, posting on the U.S. Air Quality-Smog Blog at the University of Maryland, Baltimore County, described air quality in central California in the unhealthy range. Three days later, when MODIS acquired this image, the haze remained.