energies Article Particulate Matter Produced by Micro-Scale Biomass Combustion in an Oxygen-Lean Atmosphere Jan Polácˇik 1, Ladislav Šnajdárek 1, Michal Špilácˇek 2,*, Jirˇí Pospíšil 1 and Tomáš Sitek 1 1 Energy Institute, NETME Centre, Brno University of Technology, ...