Fire has always been a vital component of nature's ecological cycle, providing for the constant regeneration of plant and animal life on earth. However, in recent decades, human intervention has often interrupted this process, resulting in an unnatural buildup of fuels and modifying local ecosystems. To reduce this hazard, officials rely on prescribed fire, the deliberate burning of wildland areas, as an essential tool for land management. These burns simulate natural processes while reducing the risk to surrounding communities. One unwanted side effect of this practice is the impact on local and regional air quality. The production of particulate matter has received significant attention due to its effects on public health. The amount of PM production relative to the amount and composition of fuel burned (the emissions factor) is an important tool for determining the impact of prescribed burns on air quality.

Field experiments to measure the emissions factor of particulates for common wildland fuels were conducted at two separate sites in the western United States. Smoke chemistry near the source was sampled using a mobile laboratory which contained aerosol and proton transfer reaction mass spectrometers, laser photometer particle detectors, fast mobility particle sizers, open-path FTIR, a condensation particle counter, a particle mass monitor, and filter sampling. Local environmental conditions were measured using an array of meteorological instruments, including sonic anemometers, solar and soil heat flux sensors, hygrometers, and temperature/relative humidity sensors.

This presentation will focus on a comparison of field-obtained emissions factors of PM2.5 and PM10 (for western chaparral and oak/savannah woodland fuels) to those obtained by laboratory measurements in 2009. An emphasis will be placed on the effect of meteorological factors, such as atmospheric dispersion, on field emissions characterization.