There was fire activity in the Plains around this time but nothing too serious. The smoke from these fires was primarily a local issue, with little drift across large distances.
Compare the image above with the one below, which shows the fire and smoke situation this past Saturday.
NOAA generates new images daily, so I’ve compiled the past 100 or so into a GIF going back to the beginning of May. It shows the ebb and flow of atmosphere smoke as North American wildfires ignite and die out. You can see the amount of smoke increase dramatically in the past few weeks.
The agency cautions that there’s room for error in its measurements. Its analysts' “ability to detect fires and smoke can be compromised by many factors, including cloud cover, tree canopy, terrain, the size of the fire or smoke plume, the time of the day, etc.”
Research has shown that even low levels of outdoor air pollution can cause notable deficits in cognitive performance and worker productivity. A 2014 study found that small particle pollution concentrations of just 20 micrograms per cubic meter — well below Environmental Protection Agency guidelines for 24-hour exposure — caused significant drops in the productivity of indoor agricultural workers, resulting in reduced pay for the workers affected.
Atmospheric smoke can cause air pollutant levels to surge well beyond those numbers. In parts of Idaho, for instance, current small particle pollutant concentrations are coming in at more than 100 micrograms per cubic meter.
So far 2018′s wildfire season has been a busy one, with a total year-to-date acreage burned well above the 10-year average. If that trend continues, expect more smoky skies heading into fall.