A dense plume of carbon monoxide moves northeast from Arizona's fires over Colorado and Nebraska, with lower amounts of the gas detectable across much of the Midwest during 1 to 12 June. Much of the Atlantic Seaboard and Southeast also experienced high levels of carbon monoxide. Some may be from the Wallow and other fires, but much of the carbon monoxide in that region typically comes from cities and other sources of pollution. (Illustration by Lex Ivey, based on data by Gabriele Pfister and the NCAR and University of Toronto MOPITT teams, UCAR.)
