May-October (wildfire season) summary for Fort Collins

The wildfire season has come to a close, so I thought I would just give a quick overview of the summer air quality as it pertains to PM_2.5.

We had several days of smoke this season, with very little of it being from local fires.  The following is a map of the CONUS showing the number of days with HMS smoke plumes from May-October 2017.

Number of days with an HMS smoke plume for the period of May 1^st - October 31^st, 2017. Data from satepsanone.nesdis.noaa.gov.

We obviously did not experience as many smoke days as the Northwest, but Fort Collins still had a significant number of days where the HMS product noted smoke compared to previous years. According to the HMS product, there were 41 days when smoke was noted over Fort Collins (2016 had 30; 2015 had 23; 2014 had 21; 2013 had 34; and 2012 had 69 days).

The maximum hourly concentration at the Fort Collins site was 106 ug/m³ and the maximum daily concentration was 60 ug/m³. (as a note, all PM data I show on this sites is from the real-time reports and have not been corrected or validated, meaning that these values may change). Both of these occurred on Labor Day (4^th of September). You can read the blog post on that event here. This was the only day where the 24-hr concentration was greater than the EPA's standard of 35 ug/m³. However, as this was due to transported wildfire smoke, it will likely be classified as an exceptional event (which means it will be excluded when determining attainment status). Below is the time series of the 24-hour average PM_2.5 concentrations in Fort Collins.

Time series of PM_2.5 concentrations in Fort Collins, CO from May through October 2017. Data from https://www.colorado.gov/airquality/.

You can see from the time series that our air quality (as it pertains to particulate matter) is generally pretty good here in Fort Collins. Most of the days with elevated PM_2.5 concentrations had smoke present. Earlier in the season (May and June), we had a few high PM days which we can't specifically attribute to smoke because the satellites do not clearly show plumes over Fort Collins. However, there were lots of fires in Mexico, Arizona, Utah, and New Mexico that were producing large smoke plumes. It is feasible that we got a little of that smoke here but that the plumes were much more diluted by the time they reached us so as not to be as distinct in the satellite images. There's also the possibility that these were due to more local sources as other monitoring sites in Colorado did not see the same PM increases. One exception would be June 27^th. The HMS plumes did not extend as far north as Fort Collins, but all of the sites around Colorado did show increases in PM_2.5 concentrations, and the HMS product did show smoke from a fire in Utah transported over all of Colorado on the 28th (we weren't on top of our blogging game during that event).

Some side thoughts: Environmental regulations have really helped improve air quality overall in the US. We have seen decreases in anthropogenic (meaning from human activity) emissions that have led to better "average" air quality. However, at the same time, we've also had lots more large wildfires that have produced extremely poor air quality for much of the western US. Reducing wildfire emissions is obviously difficult as it means stopping large wildfires before they start (land management, prescribed burns, people being more responsible, etc.). Thus, wildfire smoke is becoming an increasing health concern as it could be offsetting some of the air quality benefits gained from reductions in other emission sources. Know how to protect your health during smoke events and stay aware of current  air quality conditions!