• Journal Article

Chemical speciation of PM2.5 collected during prescribed fires of the coconino national forest near Flagstaff, Arizona

Citation

Peterson, M., Gutknecht, W., Perkins, R., Jayanty, R., & Hardison, E. (2000). Chemical speciation of PM2.5 collected during prescribed fires of the coconino national forest near Flagstaff, Arizona. Environmental Manager, 17-22.

Abstract

The use of prescribed fire is expected to increase in an effort to reduce the risk of catastrophic fire, particularly at urban/forest interfaces. Fire is a well-known source of particulate matter (PM) with particle sizes <2.5 um (PM2.5), small diameter PM known to affect climate, visibility, and human health. In this work, PM2.5 was collected during seven first-entry burns (flaming and smoldering stages) and one maintenance burn of the Coconino National Forest. Samples were analyzed for organic and elemental carbon, cations (sodium, potassium [K+], and ammonium [NH4-]), anions (nitrate [NO3-] and sulfate), and 48 elements (with atomic weights between sodium and lead). The PM2.5 contained high organic carbon levels (typically >90% by mass), commonly observed ions (K+, NH4-, and NO3-) and elements (K+, chlorine, sulfur, and silicon), as well as titanium and chromium. Flaming produced higher K+ and NH4- levels than smoldering, and the elemental signature was more complex (20 versus 7 elements). Average organic carbon x 1.4 mass fractions (+- standard deviation) were lower during flaming (92 +- 14%) than during smoldering (124 +- 24%). The maintenance (grassland) burn produced lower particle concentrations, lower NH4- and NO3- levels, and higher K and chlorine levels than did the firstentry fires.