Communicating emissions impacts to the public can sometimes be difficult because quantitatively conveying smoke concentrations is complicated. Regulators and land managers often refer to particulate-matter concentrations in micrograms per cubic meter, but this may not be intuitive or meaningful to everyone. The primary purpose of this guide is to serve as a tool for communicating potential particulate matter levels during wildfire events using visual representation. Examples of visibility impairment under various levels of smoke concentration and humidity have been modeled using the WinHaze program.
Numerous factors impact visibility; in addition to particulate matter and the presence of ozone (Aherns 2003), visibility is also affected by compounds including ammonium nitrate, ammonium sulfate, and light absorbing carbon (Malm et al. 1994), as well as relative humidity (Achtemeier et al. 2001). Existing background levels of visibility also vary across the country (Core 2001). Due to the complexity of variables, and limitations in the distances perceived by the human eye, visual approximations should be used as indicators, not precise measurement. This guide portrays potential smoke impacts to aid in communication.
Malm, William C, Sisler, James F., Huffman, Dale, Eldred, Robert A, and Cahil, Thomas A. 1994. Spatial and seasonal trended in particle concentration and optical extinction in the United States. Journal of Geophysical Research, 99,D1 1347-1370.
Core, John E. 2001. Visibility. Section 3 of. Hardy, Colin C.; Ottmar, Roger D.; Peterson, Janice L; Core, John E.; Seamon, Paula, eds. 2001. Smoke management guide for prescribed and wildland fire: 2001 edition. PMS 420-2. NFES 1279. Boise, ID: National Wildfire Coordination Group. 226 p.
Achtemeier, Gary, Brenner, James D., Core, John E., Ferguson, Sue A., Hardy, Colin C., Hermann, Sharon M., Jackson, Bill, Lahm, Peter, Leenhouts, Bill, Leuschen, Tom, Mutch, Robert E., Ottmar, Roger D., Peterson, Janice L., Reinhardt, Timothy R., Seamon, Paula, and Wade, Dale. 2001. Smoke Management Guide. A Publication of the National Wildfire Coordinating Group.
Aherns, Donald C. 2003. Meteorology Today An Introduction to Weather, Climate, and the Environment, 7th Edition. Brooks/Cole-Thomson Learning, Pacific Grove CA. 544 pages.