Wildland fire activity and associated emission of particulate matter air pollution is increasing in the United States over the last two decades due primarily to a combination of increased temperature, drought, and historically high forest fuel loading. The regulatory monitoring networks in the Unites States are mostly concentrated in larger population centers where anthropogenic air pollution sources are concentrated. Smaller population centers in areas more likely to be impacted by wildland fire smoke in many instances lack adequate observational air quality data. Several commercially available small form factor filter-based PM2.5 samplers (SFFFS) were evaluated under typical ambient and simulated near-to mid-field wildland fire smoke conditions to evaluate their accuracy for use in temporary deployments during prescribed and wildfire events. The performance of all the SFFFS tested versus the designated federal reference methods (FRM) was acceptable in determining PM2.5 concentration in both ambient (2.7–14.0 μg m−3) and chamber smoke environments (24.6–3044.6 μg m−3) with accuracies ranging from ∼92 to 98%. However, only the ARA Instruments model N-FRM Sampler was found to provide PM2.5 mass measurement accuracies that meet FRM guideline performance specifications under both typical ambient (97.3 ± 1.9%) and simulated wildland fire conditions (98.2 ± 1.4%). •ProblemoThere is a need for rugged, lightweight, battery powered, PM2.5 filter-based samplers in small and low-cost form factors that can be deployed during wildland fire events to improve spatial resolution and accuracy of PM2.5 mass measurements.oEPA partnered with the United States Forest Service (USFS) in this research effort to improve confidence in small form factor filter-based PM2.5 monitoring devices in smoke.•ApproachoThe research was performed in an ambient environment at EPA's Ambient Air Innovative Research Site (AIRS, Research Triangle Parc, NC) in 2018.oIn addition, evaluations were performed during controlled burn chamber experiments at the U.S. Forest Service Rocky Mountain Fire Sciences Laboratory in Missoula, MT in 2019.oPM2.5 FRM methods were employed as reference to assess capabilities for accurate, interference-free determination of PM2.5 in biomass smoke.•ResultsoAll samplers in the study performed respectably in determining total PM2.5 concentrations with accuracies ranging from 93.1 to 98.2%.oThe ARA N-FRM was the only small form factor filter-based sampler to achieve EPA PM2.5 FRM mass measurement accuracy performance targets along with study-best accuracies in both ambient and chamber-based smoke testing.