Merry Christmas to all of you. In the tradition of lights and trees, the air quality along the west coast continued to range between Code Yellow to Red, as shown in Airnow AQI animation. AOD readings from MODIS-Aqua are similar to the ones in Monday over California. Tropospheric NO2 concentrations from OMI throughout California were high compared to values from earlier in the week, suggesting that nitrate particulate may be the major source of PM2.5. We can't rule out the contribution of organic aerosols, as wood burning may be a major precursor of these species.