Smoke from multiple large wildfires in Canada blanketed the Great Lakes and eastern United States. The enormous smoke plume was almost 200 miles wide. The thick pall affected air quality from New York, to Baltimore, and Washington, D.C. and blocked the sunlight cooling the East Coast. The first image was taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite on July 7, 2002. The second image comes from NASA's Total Ozone Mapping Spectrometer (TOMS) on the Earth Probe Satellite.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 188.8.131.52.0