Near field pollutant and tracer dispersion during a prescribed pine forest burn

Fire is an essential ecosystem process, and prescribed burning is used to manage forest health, while preventing uncontrolled wild land fire. As prescribed burning increases and air quality regulations tighten, air quality and smoke behavior become a concern. In this work, controlled burns were conducted in a North Carolina pine forest during March, 2010 and February-March, 2011. Winds, temperature, turbulence and pollutant concentrations were measured using an array of instrumentation deployed on three tall multi-level towers and at a number of surface stations within and immediately downwind of the burn area. Additionally, a sulfur hexafluoride (SF6) tracer dispersion test was conducted where SF6 tracer was released at low rates from sources within the burn, and tracer concentrations were measured horizontally and vertically at the downwind tower location. Meteorological conditions, pollutant concentrations and tracer data are analyzed to investigate turbulence conditions and related pollutant and tracer dispersion patterns during and following the burn. The combined results are also analyzed to estimate emission factors for burn pollutants. The results will be used to improve smoke modeling tools used by land managers to assess impact of prescribed burning on air quality.