Concentrations of diesel particulate matter and polycyclic aromatic hydrocarbons (PAHs) in platinum mine environments are likely to be higher than in ambient air due to the use of diesel machinery in confined environments. Airborne PAHs may be present in gaseous or particle phases each of which has different human health impacts due to their ultimate fate in the body. Here we report on the simultaneous sampling of both phases of airborne PAHs for the first time in underground platinum mines in South Africa, which was made possible by employing small, portable denuder sampling devices consisting of two polydimethylsiloxane (PDMS) multichannel traps connected in series separated by a quartz fibre filter, which only require small, battery operated portable personal sampling pumps for air sampling. Thermal desorption coupled with comprehensive gas chromatography -mass spectrometry (TD-GCxGC-TofMS) was used to analyse denuder samples taken in three different platinum mines. The samples from a range of underground environments revealed that PAHs were predominantly found in the gas phase with naphthalene and mono-methylated naphthalene derivatives being detected at the highest concentrations ranging from 0.01 to 18 g m -3 . The particle bound PAHs were found in the highest concentrations at the idling load haul dump vehicle exhausts with a dominance of fluoranthene and pyrene. Particle associated PAH concentrations ranged from 0.47 to 260 ng m -3 and included benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene and benzo [ghi]perylene. This work highlights the need to characterise both phases in order to assess occupational exposure to PAHs in this challenging sampling environment.

Biomass burning is a significant anthropogenic source of air pollution, including the preharvest burning of sugar cane. These burn events result in atmospheric emissions, including semivolatile organic compounds, that may have adverse impacts on air quality and human health on a local, regional, and even a global scale. Gaseous and particulate polycyclic aromatic hydrocarbon (PAH) emissions from various sugar cane burn events in the province of Kwa‐Zulu Natal in South Africa were simultaneously sampled using a portable denuder sampling technology, consisting of a quartz fiber filter sandwiched between two polydimethylsiloxane multichannel traps. Total gas and particle phase PAH concentrations ranged from 0.05 to 9.85 µg m–3 per individual burn event, and nine PAHs were quantified. Over 85% of all PAHs were found to exist in the gas phase, with smaller two‐ and three‐ring PAHs, primarily naphthalene, 1‐methyl naphthalene, and acenaphthylene, being the most dominant and causing the majority of variance between the burn sites. The PAH profiles differed between the different burn events at different sites, emphasizing the significant influence that the crop variety, prevailing weather conditions, and geographical location has on the type and number of pollutants emitted. The potential carcinogenicity of the PAH exposure was estimated based on toxic equivalency factors that showed varying risk potentials per burn event, with the highest value of 5.97 ng m–3. Environ Toxicol Chem 2023;42:778–792. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

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The combustion of petroleum-based fossil fuels is associated with a high environmental burden. Several alternative fuels, including synthetic fuels (e.g., gas-to-liquid, GTL) and biofuels (e.g., rapeseed methyl ester, RME) have been studied in the last few years. While the advantages for the environment (sustainability of biofuels) are well known, research on the resulting health effects from combustion aerosols of these alternative fuels is still scarce. Consequently, we investigated the chemical combustion profile from three distinct fuel types, including a petroleum-based fossil fuel (B0) and two alternative fuels (GTL, RME) under real exposure conditions. We sampled particulate matter (PM2.5, PM0.25) and the gas phase from heavy-duty machinery and evaluated the general pattern of volatile and semi-volatile organic compounds, elemental and organic carbon as well as a range of transition metals in the size segregated PM and/or gas phase. The use of comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry enabled us to classify distinct methylated PAHs in the PM samples and its high abundance, especially in the fine fraction of PM. We found that (methylated) PAHs were highly abundant in the PM of B0 compared to GTL and RME. Highest concentrations of targeted aromatic species in the gas phase were released from B0. In summary, we demonstrated that GTL and RME combustion released lower amounts of chemical compounds related to adverse health effects, thus, the substitution of petroleum-based fuels could improve air quality for human and the environment.

Volatile and semivolatile organic compounds in ambient air and occupational settings are of great concern due to their associated adverse human health and environmental impacts. Novel graphene wool samplers have been developed and tested to overcome limitations of commercially available sorbents that can only be used once and typically require solvent extraction. Graphene wool (GW) was synthesized by non-catalytic chemical vapor deposition with optimized conditions, resulting in a novel fibrous graphene wool that is very easy to manage and less rigid than other forms of graphene, lending itself to a wide range of potential applications. Here, the air pollutant sampling capabilities of the GW were of interest. The optimal packing weight of GW inside a glass tube (length 178 mm, i.d. 4 mm, o.d. 6 mm) was investigated by the adsorption of vaporized alkane standards on the GW, using a condensation aerosol generator in a temperature-controlled chamber and subsequent detection using a flame ionization detector. The optimized GW packing density was found to be 0.19 mg mm–3 at a flow rate of 500 mL min–1, which provided a gas collection efficiency of >90% for octane, decane, and hexadecane. The humidity uptake of the sampler is less than 1% (m/m) for ambient humidities <70%. Breakthrough studies showed the favorable adsorption of polar molecules, which is attributed to the defective nature of the graphene and the inhomogeneous coating of the graphene layers on the quartz wool, suggesting that the polar versus non-polar uptake potential of the GW can be tuned by varying the graphene layering on the quartz wool substrate during synthesis. Oxidized domains at the irregular edges of the graphene layers, due to a broken, non-pristine sp2 carbon network, allow for adsorption of polar molecules. The GW was applied and used in a combustion sampling campaign where the samplers proved to be comparable to frequently used polydimethylsiloxane sorbents in terms of sampling and thermal desorption of non-polar semivolatile organic compounds. The total alkane concentrations detected after thermal desorption of GW and PDMS samplers were found to be 17.96 ± 13.27 and 18.30 ± 16.42 μg m–3, respectively; thus, the difference in the alkane sampling concentration between the two sorbent systems was negligible. GW provides a new, exciting possibility for the monitoring of organic air pollutants with numerous advantages, including high sampling efficiencies, simple and cost-effective synthesis of the thermally stable GW, solvent-free and environmentally friendly analysis, and, importantly, the reusability of samplers.