Recent studies identified the generation of oxidative stress as one of the major mechanisms by which PM exerts its adverse biological effects. The ability of PM to induce oxidative stress is frequently estimated by acellular oxidative potential (OP) assays, such as acid ascorbic (AA), 2,7-dichlorofluorescenin (DCFH) and dithiothreitol (DTT) assay, used as a proxy of ROS generation in biological systems. In this study we applied the AA, DCFH and DTT assays to PM10 samples, previously chemically analysed (Massimi et al, 2020), collected at 23 different sampling sites in Terni (an urban and industrial hot-spot of Central Italy), by using innovative and very-low volume devices for PM sampling on membrane filters (HSRS - High Spatial Resolution Sampler; Fai Instruments, Fonte Nuova, Rome, Italy). The HSRS worked in parallel during a two-month winter monitoring period. The sampling sites have been chosen for spatially representing the main local emission sources and the samplers were located in order to cover the study area with around 1 km spatial resolution (Figure 1, upper panel). In this study we aimed to assess the spatial variability of the three acellular assays (Figure 1) in order to investigate relationships between the different OP results and the contribution of the local emission sources to the total PM10. To our knowledge, the comparison of the three OP assays applied to PM10 spatially-resolved samples has never been undertaken so far. Furthermore, we applied the three OP assays to size-segregated PM samples collected by a multistage impactor (cut-sizes: 0.18, 0.32, 0.56, 1.0, 1.8, 3.2, 5.6, 10 and 18 μm) at three sampling sites (MA, CA and PR; Figure 1, upper panel), characterized by different strength of the main PM sources, in order to evaluate the different sensitivity of the three acellular assays toward fine and coarse particles. The results showed that AA was particularly sensitive toward coarse particles coming from the rail network (close to GI, CR and HG), released by the abrasion of train brakes. On the contrary, DCFH appeared to be more related to PM10 coming from industrial sources (steel plant at PR and OB) and biomass burning (domestic biomass heating at BR), while DTT was found to be sensitive only toward fine particles released by biomass burning (burning of carpentry waste products at FA and domestic biomass heating at BR). The innovative experimental approach allowed us identifying spatial relationships between PM oxidative potential and PM chemical composition and sources.

Innovative experimental approach for identifying spatial relationships between PM oxidative potential and PM chemical composition and sources

Massimi L.;Ristorini M.;Simonetti G.;Canepari S.
2020

Abstract

Recent studies identified the generation of oxidative stress as one of the major mechanisms by which PM exerts its adverse biological effects. The ability of PM to induce oxidative stress is frequently estimated by acellular oxidative potential (OP) assays, such as acid ascorbic (AA), 2,7-dichlorofluorescenin (DCFH) and dithiothreitol (DTT) assay, used as a proxy of ROS generation in biological systems. In this study we applied the AA, DCFH and DTT assays to PM10 samples, previously chemically analysed (Massimi et al, 2020), collected at 23 different sampling sites in Terni (an urban and industrial hot-spot of Central Italy), by using innovative and very-low volume devices for PM sampling on membrane filters (HSRS - High Spatial Resolution Sampler; Fai Instruments, Fonte Nuova, Rome, Italy). The HSRS worked in parallel during a two-month winter monitoring period. The sampling sites have been chosen for spatially representing the main local emission sources and the samplers were located in order to cover the study area with around 1 km spatial resolution (Figure 1, upper panel). In this study we aimed to assess the spatial variability of the three acellular assays (Figure 1) in order to investigate relationships between the different OP results and the contribution of the local emission sources to the total PM10. To our knowledge, the comparison of the three OP assays applied to PM10 spatially-resolved samples has never been undertaken so far. Furthermore, we applied the three OP assays to size-segregated PM samples collected by a multistage impactor (cut-sizes: 0.18, 0.32, 0.56, 1.0, 1.8, 3.2, 5.6, 10 and 18 μm) at three sampling sites (MA, CA and PR; Figure 1, upper panel), characterized by different strength of the main PM sources, in order to evaluate the different sensitivity of the three acellular assays toward fine and coarse particles. The results showed that AA was particularly sensitive toward coarse particles coming from the rail network (close to GI, CR and HG), released by the abrasion of train brakes. On the contrary, DCFH appeared to be more related to PM10 coming from industrial sources (steel plant at PR and OB) and biomass burning (domestic biomass heating at BR), while DTT was found to be sensitive only toward fine particles released by biomass burning (burning of carpentry waste products at FA and domestic biomass heating at BR). The innovative experimental approach allowed us identifying spatial relationships between PM oxidative potential and PM chemical composition and sources.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11573/1654259
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