Ramalho, Fernanda Maria Guedes creator Simetti, Rodrigo creator Arriel, Taiana Guimarães creator Loureiro, Breno Assis creator Hein, Paulo Ricardo Gherardi creator text periodical abstract or summary bl. continuing eng ABSTRACT The objective of this study was to evaluate the influence of particle size of charcoal samples on the predictive model statistics of charcoal chemical composition based on the NIR spectroscopy. Spectra of Acacia and of Eucalyptus charcoal were collected in the 100, 60 and 40 mesh granulometry, besides the powder remaining at the bottom of the sieves sets. They were subjected to principal component analysis and partial least square regression in order to estimate of volatile material (VMC), ash (AC) and fixed carbon content (FCC) values. The estimation of the FCC, VMC and AC of Eucalyptus based on NIR was more accurate using spectra of lower-particle-size powder. The models for Acacia charcoal were better using spectra measured at 40 mesh to predict FCC, 100 mesh for AC, and smaller size for VMC. NIR spectroscopy was efficient in estimating the immediate chemical composition of charcoal, except for AC. Keywords: wood pyrolysis, NIR, proximate chemical analysis, forest biomass. Publicação on-line; 22 ref.; 1 table; 3 illus.; Summary (En) ANÁLISE QUÍMICA CARVÃO VEGETAL BIOMASSA FLORESTA MADEIRA Rio de Janeiro-RJ Instituto de Florestas - UFRRJ 1994 2025-0453 1415-0980 / ISSN 2179-8087 0nline BR2026001307 v. 26(special number n.1) p. 1-8; (2019) https://www.scielo.br/j/floram/a/jc9K4R5nghF9rrrJbkcH3kd/?format=pdf&lang=en https://www.scielo.br/j/floram/a/jc9K4R5nghF9rrrJbkcH3kd/?format=pdf&lang=en BR-BrBNA 260504 20260504101949.0 eng