Source apportionment of PM10 and health risk assessment related in a narrow tropical valley. Study case: Metropolitan area of Aburrá Valley (Colombia).

This study investigates spatio-temporal variations of PM10 mass concentrations and associated metal(oid)s, δ13C carbon isotope ratios, polycyclic aromatic hydrocarbons (PAHs), total organic carbon (TOC) and equivalent black carbon (eBC) concentrations over a half year period (from March 2017 to October 2017) in two residential areas of Medellín (MED-1 and MED-2) and Itagüí municipality (ITA-1 and ITA-2) at a tropical narrow valley (Aburrá Valley, Colombia), where few data are available. A total of 104 samples were analysed by using validated analytical methodologies, providing valuable data for PM10 chemical characterisation. Metal(oid)s concentrations were measured by inductively coupled plasma mass spectrometry (ICP-MS) after acid digestion, and PAHs concentrations were measured by Gas Chromatography-Mass Spectrometry (GC-MS) after Pressurised Hot Water Extraction (PHWE) and Membrane Assisted Solvent Extraction (MASE). Mean PM10 mass concentration ranged from 37.0 µg m-3 to 45.7 µg m-3 in ITA-2 and MED-2 sites, respectively. Al, Ca, Mg and Na (from 6249 ng m-3 for Mg at MED-1 site to 10,506 ng m-3 for Ca at MED-2 site) were the major elements in PM10 samples, whilst As, Be, Bi, Co, Cs, Li, Ni, Sb, Se, Tl and V were found at trace levels (< 5.4 ng m-3). Benzo[g,h,i] perylene (BghiP), benzo[b + j]fluoranthene (BbjF) and indene(1,2,3-c,d)pyrene (IcdP) were the most profuse PAHs in PM10 samples, with average concentrations of 0.82-0.86, 0.60-0.78 and 0.47-0.58 ng m-3, respectively. Results observed in the four sampling sites showed a similar dispersion pattern of pollutants, with temporal fluctuations which seems to be associated to the meteorology of the valley. A PM source apportionment study were carried out by using the positive matrix factorization (PMF) model, pointing to re-suspended dust, combustion processes, quarry activity and secondary aerosols as PM10 sources in the study area. Among them, combustion was the major PM10 contribution (accounting from 32.1 to 32.9% in ITA-1 and ITA-2, respectively), followed by secondary aerosols (accounting for 13.2% and 23.3% ITA-1 and MED-1, respectively). Finally, a moderate carcinogenic risk was observed for PM10-bound PAHs exposure via inhalation, whereas significant carcinogenic risk was estimated for carcinogenic metal(oid)s exposure in the area during the sampling period.

Comparative study of atmospheric water-soluble organic aerosols composition in contrasting suburban environments in the Iberian Peninsula Coast.

This study investigates the structural composition and major sources of water-soluble organic matter (WSOM) from PM2.5 collected, in parallel, during summer and winter, in two contrasting suburban sites at Iberian Peninsula Coast: Aveiro (Portugal) and Coruña (Spain). PM10 samples were also collected at Coruña for comparison. Ambient concentrations of PM2.5, total nitrogen (TN), and WSOM were higher in Aveiro than in Coruña, with the highest levels found in winter at both locations. In Coruña, concentrations of PM10, TN, and WSOM were higher than those from PM2.5. Regardless of the season, stable isotopic δ13C and δ15N in PM2.5 suggested important contributions of anthropogenic fresh organic aerosols (OAs) at Aveiro. In Coruña, δ13C and δ15N of PM2.5 and PM10 suggests decreased anthropogenic input during summer. Although excitation-emission fluorescence profiles were similar for all WSOM samples, multi-dimensional nuclear magnetic resonance (NMR) spectroscopy confirmed differences in their structural composition, reflecting differences in aging processes and/or local sources between the two locations. In PM2.5 WSOM in Aveiro, the relative distribution of non-exchangeable proton functional groups was in the order: HC (40-43%) > HCC (31-39%) > HCO (12-15%) > Ar-H (5.0-13%). However, in PM2.5 and PM10 WSOM in Coruña, the relative contribution of HCO groups (24-30% and 23-29%, respectively) equals and/or surpasses that of HCC (25-26% and 25-29%, respectively), being also higher than those of Aveiro. In both locations, the highest aromatic contents were observed during winter due to biomass burning emissions. The structural composition of PM2.5 and PM10 WSOM in Coruña is dominated by oxygenated aliphatic compounds, reflecting the contribution of secondary OAs from biogenic, soil dust, and minor influence of anthropogenic emissions. In contrast, the composition of PM2.5 WSOM in Aveiro appears to be significantly impacted by fresh and secondary anthropogenic OAs. Marine and biomass burning OAs are important contributors, common to both sites.

Integrative health risk assessment of air pollution in the northwest of Spain.

Levels, origins and potential risks due to different air pollutants (ozone, SO2 and particle-borne metals) in NW Spain were investigated in eight locations affected by different emission sources. All monitored locations suffered the influence of traffic and industrial emissions, being this influence more important in urban locations. Although average values of the estimated hazard index (HI) due to particle-borne metals showed values lower than one, maximum values of this parameter exceeded this safety limit in urban locations. In general, Ni and As were identified as those metals most contributing to the HI. Furthermore, the presence of industrial emission episodes produced a significant increase in the magnitude of the HI in two of the seven urban areas. Therefore, the frequency and intensity of these episodes should be further investigated. Finally, levels of airborne and particle-borne pollutants were integrated with the aim of providing a comprehensive assessment of health risk. According to an established indexing system, air quality can be classified from good to moderate, being the southern urban locations (the most densely populated and industrialised ones) presenting the worst values. However, either the high or the low influence of acute and chronic-effect pollutants on air quality depends on the location.

Proposal of a procedure for the analysis of atmospheric polycyclic aromatic hydrocarbons in mosses.

A useful analytical procedure for the analysis of 19 polycyclic aromatic hydrocarbons (PAHs) in moss samples using microwave assisted extraction and programmed temperature vaporization-gas chromatography-tandem mass spectrometry (PTV-GC-MS/MS) determination is proposed. The state of art in PAHs analysis in mosses was reviewed. All the steps of the analysis were optimized regarding not only to the analytical parameters, but also the cost, the total time of analysis and the labour. The method was validated for one moss species used as moss monitor in ambient air, obtaining high recoveries (between 83-108%), low quantitation limits (lower than 2 ng g(-1)), good intermediate precision (relative standard deviation lower than 10%), uncertainties lower than 20%. Finally, the method was checked for other species, demonstrating its suitability for the analysis of different moss species. For this reason the proposed method can be helpful in air biomonitoring studies.

As, Bi, Sb and Sn determination in atmospheric particulate matter by direct solid sampling-hydride generation-electrothermal atomic absorption spectrometry.

A novel, rapid and simple method by hydride generation-electrothermal atomic absorption spectrometry (HG-ETAAS) after direct As, Bi, Sb and Sn hydrides generation from untreated filters of atmospheric particulate matter (PM(10) and PM(2.5)) was optimised. PM(10) and PM(2.5) were not subjected to any pre-treatment: circular portions between 0.28 and 6.28cm(2) were directly placed into the reaction vessel of a batch mode generation system. A 2(8)x3/64 Plackett-Burman design was used as a multivariate strategy for the evaluation of the effects of several variables affecting the hydride generation, trapping and atomisation efficiencies. Trapping temperature was the most statistically significant variable for As, Bi and Sn. Atomisation temperature was also statistically significant for Sb determination. Optimum values of significant variables were selected by using univariate optimisation approaches. An aqueous calibration method was used throughout. The developed method has been found to be precise with relative standard deviations of 6.2, 5.3, 9.1 and 7.5% for 11 determinations in a filter sample containing 0.7, 1.0, 1.4 and 1.7microg l(-1) for As, Bi, Sb and Sn, respectively. Results obtained by direct solid sampling-HG-ETAAS have been found statistically comparable with those obtained after conventional method based on an acid digestion followed to ICP-MS. Absolute detection limits were 37, 15, 30, and 41ng l(-1) for As, Bi, Sb and Sn, respectively. Detection limits referred to the air volume sampled (in the range of 0.020-0.050ng m(-3)) were low enough for the determination of several hydride-forming elements from PM(10) and PM(2.5) samples collected in a non-polluted suburban area of A Coruña (NW Spain).

Determination of aliphatic and polycyclic aromatic hydrocarbons in atmospheric particulate samples of A Coruña City (Spain).

The hydrocarbon composition of atmospheric particulate matter from A Coruña city (Northwest Spain) has been studied. TSP (total suspended particulate) and PM10 (particulate matter with aerodynamic diameter < 10 microm) samples were taken over 7 and 4 months at two stations located in residential and industrial sectors of A Coruña city, respectively. The levels of hydrocarbons found in atmospheric particulate samples of A Coruña city are higher than the ones found in other cities over the world. Ratios between the analysed compounds and their sources were established. Both anthropogenic and biogenic origins were found.