Analysis of the uncertainties in modeling and inventoring greenhouse gases and particulates from vegetation burning fire emissions

Wildland fires are one of the most source of disturbances causing ecological degradation, contributing to ecosystem changes and affecting all biosphere components. They represent one of the most significant sources of emissions in atmosphere of trace gases and aerosol particles, with a significant impact on air quality, human health, operational safety, altering the carbon budget and affecting climate change. According to the equation first proposed by Seiler and Crutzen (1980), fire emission estimation use information on the amount of burned biomass, the emission factors associated with each specific chemical species, the burned area and the combustion efficiency. Still, simulating emission from forest fires is affected by several errors and uncertainties, due to the different assessment approach to characterize the various parameters involved in the equation. For example, regional assessment relied on fire-activity reports from forest services, with assumptions regarding the type of vegetation burned, the characteristics of burning, and the burned area. Over the last decades, several studies have focused on the estimation of global fire emissions of many gaseous and particulate species through the application of several methodologies. Improvements and new advances in remote sensing, experimental measurements of emission factors, fuel consumption models, fuel load evaluation, and spatial and temporal distribution of burning are a valuable help for predicting and quantifying accurately the source and the composition of fire emissions. but despite new advances in modelling and improvement of the knowledge of fires and the connected emissions have been made, due to the use of different approaches and datasets used for fire emissions components, several uncertainties and errors still exist, and a multi-year comprehensive inventory of the fire incidence and inherent fire emissions in Italy is missing. In this work, we first carried out a comprehensive literature of fire emission, highlighting the principal methodologies and related uncertainties. Then, we estimated the FE derived from fires that occurred in Italy during the period 2007-2017, using an integrated methodology combining a fire emissions model with spatial and non-spatial inputs related on fire characteristics, vegetation and weather conditions. Finally, through the analysis of six forest fires occurred in Italy at particular severe conditions during 2017, we evaluated the main sources of uncertainties in the estimation of fire emissions combining two fire size information sources, and two methods for identifying fire severity and thus fuel consumption. This study provides insight to better inform a long-standing fire incidence in Italy and the resulting effects. Our results are valuable for providing data for emissions source models coupled with dispersion models and decision support systems, crucial for air quality managements, mitigation of wildland fire environmental effects, and to assist decision makers in prescribed fire activities in order to help the development of more accurate emissions inventories at a national scale and in the framework of Kyoto Protocol reporting activities for the LULUCF (Land Use, Land Use Change and Forestry) sector.