The high levels of PM2.5 reported in previous days persisted into this morning, but faded throughout the day. The large spot of unhealthy levels of PM2.5 and surrounding moderate levels of PM2.5 in California faded to a much smaller spot of moderate levels of PM2.5 by evening. This region of PM2.5 correlated with the Unhealthy and Moderate AQI shown in the adjacent image. Moderate air quality steadily covered much of the Northeast US, expanding slightly as the day advanced. This is correlated with the PM2.5. Another spot of moderate air quality was reported over the Rocky Mountains.
The HMS image shows a large spot of fires continuing to burn in the southern US, as well as a nearby smoke plume over the Gulf of Mexico. Fires also burn in the Pacific Northwest.
The image below, from NASA Earth Observatory on December 16th, shows the Pheiffer Fire in California producing a smoke plume over both the sea and coastal land. Local media reports indicate the fire continues to burn today as fire crew continue to contain the fire.