Ambient air particulate total lung deposited surface area (LDSA) levels in urban Europe.

This study aims to picture the phenomenology of urban ambient total lung deposited surface area (LDSA) (including head/throat (HA), tracheobronchial (TB), and alveolar (ALV) regions) based on multiple path particle dosimetry (MPPD) model during 2017-2019 period collected from urban background (UB, n = 15), traffic (TR, n = 6), suburban background (SUB, n = 4), and regional background (RB, n = 1) monitoring sites in Europe (25) and USA (1). Briefly, the spatial-temporal distribution characteristics of the deposition of LDSA, including diel, weekly, and seasonal patterns, were analyzed. Then, the relationship between LDSA and other air quality metrics at each monitoring site was investigated. The result showed that the peak concentrations of LDSA at UB and TR sites are commonly observed in the morning (06:00-8:00 UTC) and late evening (19:00-22:00 UTC), coinciding with traffic rush hours, biomass burning, and atmospheric stagnation periods. The only LDSA night-time peaks are observed on weekends. Due to the variability of emission sources and meteorology, the seasonal variability of the LDSA concentration revealed significant differences (p = 0.01) between the four seasons at all monitoring sites. Meanwhile, the correlations of LDSA with other pollutant metrics suggested that Aitken and accumulation mode particles play a significant role in the total LDSA concentration. The results also indicated that the main proportion of total LDSA is attributed to the ALV fraction (50 %), followed by the TB (34 %) and HA (16 %). Overall, this study provides valuable information of LDSA as a predictor in epidemiological studies and for the first time presenting total LDSA in a variety of European urban environments.

Phenomenology of ultrafine particle concentrations and size distribution across urban Europe.

The 2017-2019 hourly particle number size distributions (PNSD) from 26 sites in Europe and 1 in the US were evaluated focusing on 16 urban background (UB) and 6 traffic (TR) sites in the framework of Research Infrastructures services reinforcing air quality monitoring capacities in European URBAN & industrial areaS (RI-URBANS) project. The main objective was to describe the phenomenology of urban ultrafine particles (UFP) in Europe with a significant air quality focus. The varying lower size detection limits made it difficult to compare PN concentrations (PNC), particularly PN10-25, from different cities. PNCs follow a TR > UB > Suburban (SUB) order. PNC and Black Carbon (BC) progressively increase from Northern Europe to Southern Europe and from Western to Eastern Europe. At the UB sites, typical traffic rush hour PNC peaks are evident, many also showing midday-morning PNC peaks anti-correlated with BC. These peaks result from increased PN10-25, suggesting significant PNC contributions from nucleation, fumigation and shipping. Site types to be identified by daily and seasonal PNC and BC patterns are: (i) PNC mainly driven by traffic emissions, with marked correlations with BC on different time scales; (ii) marked midday/morning PNC peaks and a seasonal anti-correlation with PNC/BC; (iii) both traffic peaks and midday peaks without marked seasonal patterns. Groups (ii) and (iii) included cities with high insolation. PNC, especially PN25-800, was positively correlated with BC, NO2, CO and PM for several sites. The variable correlation of PNSD with different urban pollutants demonstrates that these do not reflect the variability of UFP in urban environments. Specific monitoring of PNSD is needed if nanoparticles and their associated health impacts are to be assessed. Implementation of the CEN-ACTRIS recommendations for PNSD measurements would provide comparable measurements, and measurements of <10 nm PNC are needed for full evaluation of the health effects of this size fraction.

Geochemistry and oxidative potential of the respirable fraction of powdered mined Chinese coals.

This study evaluates geochemical and oxidative potential (OP) properties of the respirable (finer than 4 µm) fractions of 22 powdered coal samples from channel profiles (CP4) in Chinese mined coals. The CP4 fractions extracted from milled samples of 22 different coals were mineralogically and geochemically analysed and the relationships with the OP evaluated. The evaluation between CP4/CP demonstrated that CP4 increased concentrations of anatase, Cs, W, Zn and Zr, whereas sulphates, Fe, S, Mo, Mn, Hf and Ge decreased their CP4 concentrations. OP results from ascorbic acid (AA), glutathione (GSH) and dithiothreitol (DTT) tests evidenced a clear link between specific inorganic components of CP4 with OPAA and the organic fraction of OPGSH and OPDTT. Correlation analyses were performed for OP indicators and the geochemical patterns of CP4. These were compared with respirable dust samples from prior studies. They indicate that Fe (r = 0.83), pyrite (r = 0.66) and sulphate minerals (r = 0.42) (tracing acidic species from pyrite oxidation), followed by S (r = 0.50) and ash yield (r = 0.46), and, to a much lesser extent, Ti, anatase, U, Mo, V and Pb, are clearly linked with OPAA. Moreover, OPGSH correlation was identified by organic matter, as moisture (r = 0.73), Na (r = 0.56) and B (r = 0.51), and to a lesser extent by the coarse particle size, Ca and carbonate minerals. In addition, Mg (r = 0.70), B (r = 0.47), Na (r = 0.59), Mn, Ba, quartz, particle size and Sr regulate OPDTT correlations. These became more noticeable when the analysis was done for samples of the same type of coal rank, in this case, bituminous.

Mineralogy, geochemistry and toxicity of size-segregated respirable deposited dust in underground coal mines.

We focus on a comparison of the geochemistry and mineralogy patterns found in coal, deposited dust (DD), respirable deposited dust (RDD) and inhalable suspended dust (PM10) from a number of underground mines located in China, with an emphasis on potential occupational health relevance. After obtaining the RDD from DD, a toxicological analysis (oxidative potential, OP) was carried out and compared with their geochemical patterns. The results demonstrate: i) a dependence of RDD/DD on the moisture content for high rank coals that does not exist for low rank coals; ii) RDD enrichment in a number of minerals and/or elements related to the parent coal, the wear on mining machinery, lime gunited walls and acid mine drainage; and iii) the geochemical patterns of RDD obtained from DD can be compared with PM10 with relatively good agreement, demonstrating that the characterization of DD and RDD can be used as a proxy to help evaluate the geochemical patterns of suspended PM10. With regards to the toxicological properties of RDD, the Fe content and other by-products of pyrite oxidation, as well as that of anatase, along with Si, Mn and Ba, and particle size (among others), were highly correlated with Ascorbic Acid and/or Glutathione OP.

Determination of Pd(II) using an antimony film coated on a screen-printed electrode by adsorptive stripping voltammetry.

The use of an antimony film coated on a screen-printed carbon electrode (ex-situ SbSPCE) is proposed for the determination of Pd(II) at ppb levels in natural samples by adsorptive stripping voltammetry using dimethylglyoxime as chelating agent. Ex-situ SbSPCE produces a better analytical performance as compared to a commercially sputtered bismuth screen-printed electrode (BispSPE). The detection and quantification limits were 2.7 and 9.0µgL-1 respectively with a good linear behaviour in the wide examined concentration range (from 1µgL-1 up to 100.0µgL-1, R2=0.998). The proposed ex-situ SbSPCE showed an excellent repeatability with a relative standard deviation of 0.5% for ten successive measurements and a very good reproducibility (1.6% for three different ex-situ SbSPCE units within series of ten repetitive assays). Moreover, the ex-situ SbSPCE was successfully applied for the determination of low concentration levels of Pd(II) in spiked tap water with a very high reproducibility (0.2%) and providing equivalent results to those achieved by ICP-MS measurements.