Estimate Contribution of Prescribed Rangeland Burning in Kansas to Ambient PM2.5 through Source Apportionment with Unmix Receptor Model

Abstract

The Unmix receptor model was applied to the 2002-2014 speciated PM 2.5 data from the IMPROVE site at Tallgrass National Preserve near Strong City, Kansas, to investigate the contributions of prescribed rangeland burning on local air quality. This investigation found the following five source categories that contribute to annual local ambient PM 2.5 : nitrate/agricultural (22%), vegetative burning (5%), secondary organic aerosol (29%), sulfate/industrial (30%), and crustal/soil (14%). In the month of April, the contributions of vegetative burning and secondary organic aerosol increased to 11% and 49%, respectively, indicating the influence of the prescribed burning season. The contribution of smoke from prescribed burning was estimated to be 1.05 g m-3 as primary aerosols and 4.03 g m-3 as secondary aerosols, which in total accounted for 42% of the average PM 2.5 concentration in April.