Fig. 1
The combustion-derived BDS particle aerosols are composed mainly of PAH-rich (pyrene, acepyrene, anthracene and fluoranthene) fine sized (< PM2.5) agglomerated particles, (a) Electron microscopy images 1- scanning electron microscopy and 2- transmission electron microscopy) of BDS showing spherical, uniformly sized (20–40 nm diameter) primary particles, that have bundled into branches, chain-like shaped agglomerates that can reach the micrometer size range. b Particle size distributions of the aerosols show that > 90 % of the particles present are in the fine size range (PM2.5), and are composed of agglomerated individual ultrafine (<100 nm) particles [38]