LAUSR

This review summarizes our current knowledge on the health and environmental impact as well as the mineralogical and geochemical composition of nanoparticles (NPs) associated with coal fires. It will furthermore recommend new sampling and characterization protocols to gain a better understanding of the various types of NPs that are either formed through high-Temperature (T) nucleation and alteration processes or via low-T dissolution-reprecipitation and weathering processes. Coal fires impact the immediate environments of coal-producing areas and produce positive and negative feedback to climate change through the emission of carbon- and sulfate-bearing gasses and aerosols, respectively. Nanoparticles form during and after coal fires. They are composed of mainly soot and tar particles as well as amorphous phases, minerals, and complex mixtures of amorphous phases and minerals. It is recommended that NPs for mineralogical studies should be collected via impactors, a new generation of collectors for particulate matter such as the TPS100 nanoparticle sampler or borosilicate filters at the opening of pipes and chambers used to measure and collect gases emitted by coal fires. Furthermore, assemblages of NPs occurring at the mount of coal fire vents should be examined using a combination of the focussed ion beam (FIB) technology and transmission electron microscopy (TEM) and those containing ion- or electron-beam sensitive phases with the corresponding cryo-techniques such as cryo-FIB, cryo-ion mill, and cryo-TEM. The mineralogical and chemical composition of NP-bearing bulk samples should be examined with spectroscopy techniques such as X-ray photoelectron spectroscopy, 13 C nuclear magnetic resonance spectroscopy or time-of-flight secondary ion mass spectroscopy. This article is protected by copyright. All rights reserved.