Fine and ultrafine particle emission factors and new diagnostic ratios of PAHs for peat swamp forest fires

Nobchonnee Nim; John Morris; Perapong Tekasakul; Racha Dejchanchaiwong

doi:10.1016/j.envpol.2023.122237

Fine and ultrafine particle emission factors and new diagnostic ratios of PAHs for peat swamp forest fires

Environ Pollut. 2023 Oct 15:335:122237. doi: 10.1016/j.envpol.2023.122237. Epub 2023 Jul 20.

Authors

Nobchonnee Nim¹, John Morris², Perapong Tekasakul³, Racha Dejchanchaiwong⁴

Affiliations

¹ Air Pollution and Health Effect Research Center, Prince of Songkla University, Songkhla, 90110, Thailand; Energy Technology Program, Department of Specialized Engineering, Faculty of Engineering, Prince of Songkla University, Songkhla, 90110, Thailand.
² School of Industrial Education and Technology, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand.
³ Air Pollution and Health Effect Research Center, Prince of Songkla University, Songkhla, 90110, Thailand; Department of Mechanical and Mechatronics Engineering, Faculty of Engineering, Prince of Songkla University, Songkhla, 90110, Thailand.
⁴ Air Pollution and Health Effect Research Center, Prince of Songkla University, Songkhla, 90110, Thailand; Department of Chemical Engineering, Faculty of Engineering, Prince of Songkla University, Songkhla, 90110, Thailand. Electronic address: racha.d@psu.ac.th.

PMID: 37481028
DOI: 10.1016/j.envpol.2023.122237

Abstract

Peatland fires are one of the major global sources of atmospheric particles. Emission factors for fine (PM₁ and PM_2.5) and ultrafine (PM_0.1) particles and particle-bound polycyclic aromatic hydrocarbons (PAHs) from plants in the peat swamp forest (PSF), including Melaleuca cajuputi leaves, M. cajuputi branches, M. cajuputi bark, Lepironia articulata (Retz.) Domin, forest leaf litter and peat were measured in a laboratory combustion chamber. From these measurements, new PAH diagnostic ratios for fine and ultrafine particles were proposed for identifying the forest burning source. The new emission factors for PM were PM_0.1: 0.03-0.33, PM₁: 0.69-2.11 and PM_2.5: 1.12-4.18 g/kg; for PM-bound PAHs, the factors were PM_0.1: 5.7-166.0, PM₁: 31.5-1338.9 and PM_2.5: 36.3-3641.1 μg/kg. The predominant PAHs for PSF burning were Pyr, BbF, DBA (in PM_0.1), Flu, DBA, BghiPe (in PM₁), and BbF, DBA and BghiPe (in PM_2.5). We also presented new diagnostic ratios for PSF burning, including BaP/(BaP + Chr): 0.39-0.75, BaP/(BaP + BbF): 0.21-0.47 and BaA/(BaA + Chr): 0.36-0.53. Moreover, the physical and chemical characteristics of ambient fine and ultrafine particles in the Kuan Kreng forest during the 2019 forest fire (FF) and 2021 non-forest fire (NFF) periods were investigated. The mean PM_0.1, PM₁ and PM_2.5 concentrations during the FF period were approximately 3.5-4.4 times as high as those during the 2021 NFF period. New PAH diagnostic ratios of BaP/(BaP + BbF) versus BaP/(BaP + Chr) were able to identify PAH burning sources in PM₁ and PM_2.5 but were less clear for PM_0.1, which was dominated by a single source - M. cajuputi. Chemical mass balance studies identified peat forest burning emissions as the main source of fine and ultrafine particles during the FF period. This study suggests that the new PAH diagnostic ratios can be used to identify the burning source for more precise source apportionment.

Keywords: Emission factor; PAH diagnostic ratios; PM(0.1); Peat fire; Source apportionment.

MeSH terms

Air Pollutants* / analysis
Environmental Monitoring
Particulate Matter / analysis
Polycyclic Aromatic Hydrocarbons* / analysis
Soil
Wetlands

Substances

Particulate Matter
Air Pollutants
Soil
Polycyclic Aromatic Hydrocarbons