Tracers from Biomass Burning Emissions and Identification of Biomass Burning

Wenjing Li,Yan Cui,Pengxiang Ge,Mindong Chen,Dongyang Nie,Maoyu Cao,Jiajie Tang,Kun Hu

doi:10.3390/atmos12111401

Abstract

The major organic compositions from biomass burning emissions are monosaccharide derivatives from the breakdown of cellulose, generally accompanied by small amounts of straight-chain, aliphatic, oxygenated compounds, and terpenoids from vegetation waxes, resins/gums, and other biopolymers. Levoglucosan from cellulose can be utilized as a specific or general indicator for biomass combustion emissions in aerosol samples. There are other important compounds, such as dehydroabietic acid, syringaldehyde, syringic acid, vanillic acid, vanillin, homovanillic acid, 4-hydroxybenzoic acid, and p-coumaric acid, which are additional key indicators of biomass burning. In this review, we will address these tracers from different types of biomass burning and the methods used to identify the sources in ambient aerosols. First, the methods of inferring biomass burning types by the ratio method are summarized, including levoglucosan/mannose, syringic acid/vanillic acid, levolgucosan/K+, vanillic acid/4-hydroxybenzoic acid, levoglucosan/OC, and levoglucosan/EC to infer the sources of biomass burning, such as crop residual burning, wheat burning, leaf burning, peatland fire, and forest fire in Asia. Second, we present the source tracer ratio methods that determine the biomass combustion types and their contributions. Finally, we introduce the PCA (Principal component analysis) and PMF (Positive matrix factor) methods to identify the type of biomass burning and its contributions according to emission factors of different species in various plants such as softwood, hardwood, and grass.

Highlights

Biomass burning such as wildfire, agricultural open-burning, residential biofuel combustion, forest fire, grass burning, and peatland fire can produce and release substantial amounts of pollutants into the atmosphere [1,2]
In our previous study [106], SO2 was selected as the tracer for coal burning, and the concentration of levoglucosan was divided into two parts (Equation (3)): the concentration of levoglucosan from coal burning ([Levoglucosan]coal) and the concentration of levoglucosan from other types of biomass burning ([Levoglucosan]other)
Positive matrix factor analysis is an effective technique for source analysis, which estimates the composition of pollution sources and their contribution to the environmental concentration based on measured data at the receptor site

Summary

Introduction

Biomass burning such as wildfire, agricultural open-burning, residential biofuel combustion, forest fire, grass burning, and peatland fire can produce and release substantial amounts of pollutants into the atmosphere [1,2]. Angiosperm lignin contains high levels of the coniferyl and sinapyl alcohol subunits, which are the precursors of oxidation and pyrolysis products of syringol and methoxyphenol [28] Hardwoods, such as oak, have rich quantities of syringic acid and syringaldehyde in their smoke. In order to have a good knowledge of organic tracers released from grass burning, previous studies collected aerosol samples from the smoke of mixed ryegrasses consisting dominantly of n-alkanoic acids, levoglucosan, and phenolic compounds, including syringyl acetone, catechol, guaiacyl acetone, dimethoxyphenol, syringic acid, vanillyl acetic acid, and vanillic acid [17]. Other studies have found that the burning of grass mainly releases p-anisic acid, p-anisaldehyde, and minor amounts of other p-coumaryl, vanillyl, and syringyl-type lignin pyrolysis products such as p-coumaric acid, 4-hydroxybenzoic acid, and syringic acid [12,17]. The relative proportion of these compounds can be used to identify grass burning

Cellulose

Application of PCA

Application of Source Tracer Ratio

Introduction of PMF

The Application of PMF

Summary and Perspectives