Happy New Year! Code Yellow to Orange (Moderate-Unhealthy) PM2.5 AQI were reported once again in the southwestern United States, as shown in the Airnow PM2.5 AQI animations. Moderate AQI were also observed along the south, Great Lakes, New England and north Mid-Atlantic states. MODIS Aqua AOD retrievals show that values as high as 0.5 being observed over California. The air quality in the southwest was exacerbate by last night New Year firework festivities. The smoke plumes arising from such events can raise atmospheric PM levels from tens to thousands ug/m3, with most particles being 1-2 microns in diameter. The chemistry of these plumes is complex but can be characterized by the high metal content due to the present of potassium in the black powder propellant and metals/metalloids used that add color and special effects.The bottom right image is a PM2.5 timeseries of monitors that measured high concentrations along northern California and Arizona between the last hours of 2013 and the first few hours of 2014. PM2.5 concentrations in California and Arizona ranged from 40-100 and 150-900 ug/m3, respectively.