Forest Fires in the Brazilian Amazon and their Effects on Particulate Matter Concentration, Size Distribution, and Chemical Composition

ABSTRACT

The number of fires in the Brazilian Amazon rainforest has increased in recent years. Particulate matter emitted from these fires can affect different locations, depending on air mass trajectories. Characterization of such particles can help to analyze their effects. In the present work, particulate matter smaller than 2.5 µm from forest fires was evaluated in terms of particle size distribution, concentration, water-soluble organic compounds (WSOC), and water-soluble ions. The influence of combustion phases on the particulate matter emissions was investigated. Data were collected from a forest fire experiment conducted in the Brazilian Amazon (town of Candeias do Jamari, State of Rondônia), under real conditions, where the samples were taken directly from the smoke plume. The results showed that the concentration and diameter of the particles changed significantly depending on the combustion phase. Particle sizes ranged from 0.066 to 0.275 µm. The highest concentration of PM_2.5 was found in the flaming phase (140000 μg m⁻³). Concentrations of sulfate, potassium, phosphate, ammonium, formate and WSOC presented significant differences when compared among the burning test and smoldering samplings. The burning test presented the highest concentration of WSOC (800 μg m⁻³ for the particles smaller than 0.4 μm). The potassium concentration was significantly higher during the burning test. Ions containing N, S, P, and K represented the highest percentage of particle mass. These chemical species act as macronutrients and may cause an environmental imbalance in natural forests. Furthermore, the presence of sulfate and nitrate in the analyzed samples can contribute to acid deposition.

KEYWORDS:

• Amazonian deforestation fire
• combustion phases
• particulate matter emission
• chemical compounds

Highlights

• PM_2.5 was sampled directly in the smoke plume, during a real Amazon forest fire;

• PM_2.5 was characterized by its concentration, size distribution, and chemical composition;

• The possible influence of the burning phase on PM_2.5 emission was analyzed;

• The highest PM_2.5 concentration and smallest diameter were found for flaming phase;

• Burning test presented the highest concentration of WSOC, and potassium.

Acknowledgments

This work was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo – FAPESP (grant number 2008/04490–4).

The experiment in Candeias do Jamari was conducted under authorization of CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) and SEDAM (Secretaria de Estado do Desenvolvimento Ambiental de Rondônia).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

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Additional information

Funding

This work was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) [2008/04490–4].