When I woke up Monday morning, it was so dark and hazy. I checked the PM2.5 concentrations, and I was pretty surprised how high the concentrations were for not having a fire nearby. Concentrations were over 100 ug/m3 overnight (shown in time series below)! In the following plot, I am showing you a longer time series than I usual do, so that you can see normal summertime concentrations (August 24/25), the slightly smoky days like we've been seeing a lot of this summer (August 29-31), and then this event from the past weekend.
|Time series of PM2.5 concentrations measured in Fort Collins (blue) and Greeley (orange) for August 22 through September 5, 2017 (dashed lines indicate start of new day). Data from https://www.colorado.gov/airquality/.|
I went out and took the following pictures in my neighborhood in Laporte.
|Looking east (left) and west (right) from Laporte at 7:45 AM on September 4, 2017.|
Air Quality Health Advisory for Wildfire Smoke
Issued for areas below 7000 ft. in eastern ColoradoIssued at 9:30 AM MDT, Monday, September 4, 2017
Issued by the Colorado Department of Public Health and Environment
Affected Area: Areas below 7000 ft. in eastern Colorado. Locations include, but are not limited to Denver, Boulder, Ft. Collins, Greeley, Colorado Springs, Pueblo, Ft Morgan, Sterling, Julesburg, Holyoke, Boulder, Broomfield, Brighton, Littleton, Akron, Wray, Castle Rock, Kiowa, Hugo, Burlington, Cheyenne Wells, Ordway, Eads, La Junta, Las Animas, Lamar, Trinidad and Springfield.
Advisory in Effect: 9:30 AM MDT, Monday, September 4, 2017 to 9:00 AM MDT, Tuesday, September 5, 2017
Public Health Recommendations: If smoke is thick or becomes thick in your neighborhood you may want to remain indoors. This is especially true for those with heart disease, respiratory illnesses, the very young, and the elderly. Consider limiting outdoor activity when moderate to heavy smoke is present. Consider relocating temporarily if smoke is present indoors and is making you ill. If visibility is less than 5 miles in smoke in your neighborhood, smoke has reached levels that are unhealthy.
Outlook: Moderate to heavy smoke from fires in the northwestern US and western Canada is being transported into eastern Colorado. Smoke will slowly decrease Monday afternoon and evening, however due to the lingering health impacts of fine particulate concentrations we urge the public to continue to follow the health recommendations listed above through at least Tuesday morning.
My co-workers and I started trying to figure out where the smoke was originating. The HMS fire product showed that there was a fire west of Fort Collins near Walden, CO, but the satellite images seemed to show this smoke was coming from the north.
|HMS smoke and fire products for 4 September 2017 in the AM (left) and PM (right).|
|Looking south/southeast from North Bay at Horsetooth Reservoir on June 4, 2017 (left) and September 4, 2017 (right).|
|Time series of PM2.5 concentrations measured at two Denver sites: La Casa (blue) and CAMP (orange) for August 22 through September 5, 2017 (dashed lines indicate start of new day). Data from https://www.colorado.gov/airquality/.|
|Image of Denver at 4 PM on September 4th 2016 (left) and 2017 (right). From https://www.colorado.gov/airquality/live_image.aspx.|