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Modeling crop residue burning experiments and assessing the fire impacts on air quality
Citation:
Zhou, L., K. Baker, S. Napelenok, G. Pouliot, R. Elleman, David-C Wong, S. O'Neill, AND S. Urbanski. Modeling crop residue burning experiments and assessing the fire impacts on air quality. 16th Annual CMAS Conference, Chapel Hill, North Carolina, October 23 - 25, 2017.
Impact/Purpose:
Crop residue burning is commonly used in agricultural land management to dispose crop residue and provide other benefits such as pest control and ash generation for fertilization. Pollution from biomass burning has been linked to negative human health impacts. In addition, particles emitted from fires have direct radiative effects and contribute cloud condensation nuclei which have indirect cloud effects. Modelling tools including photochemical transport models have been used to support scientific and regulatory assessments that quantify the impact of specific sectors, wildland fire, and specific wildland fires to model predicted O3 and PM2.5. Meteorological input fields and fire emissions both contribute to differences between model prediction and ambient measurement. Numerous laboratory experiments have been conducted to quantify biomass burning emission factors, but the accuracy of applying these emission factors for open biomass burning is still uncertain. In addition to the magnitude of emission rates, the spatial and temporal allocation of emissions are critical to sufficiently describing fire smoke impacts. In particular, the plume-rise height is important in terms of how fire emissions are transported and chemically transformed which impacts total residence time in the atmosphere.
Description:
Prescribed burning is a common land management practice that results in ambient emissions of a variety of primary and secondary pollutants with negative health impacts. The community Multiscale Air Quality (CMAQ) model is used to conduct 2 km grid resolution simulations of prescribed burning experiments in southeast Washington state and western Idaho state in summer of 2013. The ground and airborne measurements from the field experiment are used to evaluate the model performance in capturing surface and aloft impacts from the burning events. The results suggest that in addition to specification of accurate meteorological conditions and emission estimates, plume rise calculation and vertical emission allocation based on flaming and smoldering are all important factors for robust estimation of the air quality impacts due to fires.
