Peat fuels representing four biomes of boreal (western Russia and Siberia), temperate (northern Alaska, U.S.A.), subtropical (northern and southern Florida, U.S.A), and tropical (Borneo, Malaysia) regions were burned in a laboratory chamber to determine gas and particle emission factors (EFs). Tests with 25 % fuel moisture were conducted with predominant smoldering combustion conditions (average modified combustion efficiency [MCE] = 0.82 ± 0.08). Average fuel-based EFCO<sub>2</sub> (carbon dioxide) are highest (1400 ± 38 g kg<sup>−1</sup>) and lowest (1073 ± 63 g kg<sup>−1</sup>) for the Alaskan and Russian peats, respectively. EFCO (carbon monoxide) and EFCH<sub>4</sub> (methane) are ~12 %‒15 % and ~0.3 %‒0.9  % of EFCO<sub>2</sub>, in the range of 157‒171 g kg<sup>−1</sup> and 3‒10 g kg<sup>−1</sup>, respectively. EFs for nitrogen species are at the same magnitude of EFCH<sub>4</sub>, with an average of 5.6 ± 4.8 and 4.7 ± 3.1 g kg<sup>−1</sup> for EFNH<sub>3</sub> (ammonia) and EFHCN (hydrogen cyanide); 1.9 ± 1.1 g kg<sup>−1</sup> for EFNO<sub><i>x</i></sub> (nitrogen oxides); as well as 2.4 ± 1.4 and 2.0 ± 0.7 g kg<sup>−1</sup> for EFNO<sub><i>y</i></sub> (reactive nitrogen) and EFN<sub>2</sub>O (nitrous oxide). An oxidation flow reactor (OFR) was used to simulate atmospheric aging times of ~2 and ~7 days to compare fresh (upstream) and aged (downstream) emissions. Filter-based EFPM<sub>2.5</sub> varied by >4-fold (14‒61 g kg<sup>−1</sup>) without appreciable changes between fresh and aged emissions. The majority of EFPM<sub>2.5</sub> consists of EFOC (organic carbon), with EFOC/EFPM<sub>2.5</sub> ratios in the range of 52 %‒98 % for fresh emissions, and ~15 % degradation after aging. Reductions of EFOC (~7‒9 g kg<sup>−1</sup>) after aging are most apparent for boreal peats with the largest degradation in organic carbon that evolves at <140 °C, indicating the loss of high vapor pressure semi-volatile organic compounds upon aging. The highest EFLevoglucosan is found for Russian peat (~16 g kg<sup>−1</sup>), with ~35 %‒50 % degradation after aging. EFs for water-soluble OC (EFWSOC) accounts for ~20 %‒62 % of fresh EFOC. The majority (>95 %) of the total emitted carbon is in the gas phase with 54 %‒75 % CO<sub>2</sub>, followed by 8 %‒30 % CO. Nitrogen in the measured species explains 24 %‒52 % of the consumed fuel nitrogen with an average of 35 ± 11 %, consistent with past studies that report ~one- to two-thirds of the fuel nitrogen measured in biomass smoke. The majority (>99 %) of the total emitted nitrogen is in the gas phase, with an average of 16.7 % fuel N emitted as NH<sub>3</sub> and 9.5 % of fuel N emitted as HCN. N<sub>2</sub>O and NO<sub><i>y</i></sub> constituted 5.7 % and 2.9 % of consumed fuel N. EFs from this study can be used to refine current emissions inventories.