Smoke in Colorado August 1-4, 2017

While I was in Montana (which was completely blanketed in smoke the whole time I was there), Colorado also got some wildfire smoke. There are lots of fires in BC, WA, ID, and MT, so it is difficult to tell exactly where all the smoke came from originally. However, it got here and did degrade the air quality in Fort Collins. You are probably noticing an overall theme, which is that most of our significant particulate pollution events are due to wildfires, both from local and distant fires. Thus, most of these blog posts are about wildfire smoke. Unfortunately, I do not have any cool sunset pictures as I was away last week, but I will show what the impact was on our PM_2.5 concentrations and the satellite view of smoke over northern Colorado.

We can see from the time series above that PM_2.5 concentrations were slightly elevated on August 1st - August 4th, which does correspond to smoke over the area as shown in the plots below. There was a lot of variability as the wind shifted smoke plumes around. Another thing to remember when comparing the time series to the plots below, is that these smoke plumes are determined from satellite images. Satellites see the whole atmosphere and not just the surface. Satellites "see" smoke over northern Colorado on many days when there is no corresponding increase in surface PM_2.5 concentrations. Sometimes smoke can be lofted above our heads (especially when it has been transported a long way); visibility may be impacted but not necessarily our health.

HMS Smoke Plumes over northern Colorado on August 1^st AM, August 1^st PM, August 2^nd AM, August 3^rd AM, August 4^th AM, and August 4^th PM. 

You could also see the smoke in the MODIS (true color) satellite image over Colorado on August 2^nd and 4^th. The bright white is cloud and the gray "wisps" are smoke. You can probably see why it might have been difficult for someone on the ground to tell smoke from the clouds with it all layered together!

MODIS Terra true color image from August 2^nd and August 4^th, 2017. Retrieved from https://worldview.earthdata.nasa.gov.