Concentration and source origin of lanthanoids in the Canadian atmospheric particulate matter: a case study

AbstractAmbient PM2.5 and PM2.5–10 samples collected at selected urban and rural sites within the Canadian National Air Pollution Surveillance (NAPS) PM2.5 Speciation Program were analyzed for lanthanoids and other elements. The average concentrations of total lanthanoids (calculated as sum of concentrations of all elements) in PM2.5 ranged from 0.059 to 0.334ng m−3. These concentrations were two times lower than in PM2.5–10 samples and generally lower than values reported for industrial and urban areas around the world. The highest concentrations of lanthanoids were found in PM2.5 samples collected at the Halifax NS site, located near a petroleum refining complex. In addition, La/Ce and La/Sm ratios at this site were significantly higher than their natural values. Increased La–enrichment factors were also found in Wallaceburg ON, which is located in a rural area, about 50km downwind of two major petrochemical complexes. The results of this study demonstrate that La–enrichment factors are reliable tracers of emissions from oil refining industry

Contrasting biological potency of particulate matter collected at sites impacted by distinct industrial sources

Association of biological effects in A549 cells with metal content in size-fractionated particles. Cytotoxic potencies according to lactate dehydrogenase (LDH) release and resazurin reduction were regressed against total, water-soluble, and non-water-soluble metals. Pearson product–moment correlation coefficient r-values are presented. LDH release. A) Total metals. UFP, r = 0.77, p = 0.13; PM0.1–2.5, r = −0.55, p = 0.34; PM2.5–10, r = 0.32, p = 0.60; PM>10, r = −0.68, p = 0.21. B) Water-soluble metals. UFP, r = 0.51, p = 0.38; PM0.1–2.5, r = −0.64, p = 0.25; PM2.5–10, r = −0.35, p = 0.57; PM>10, r = −0.68, p = 0.20. C) Non-water-soluble metals. UFP, r = 0.75, p = 0.14; PM0.1–2.5, r = −0.46, p = 0.43; PM2.5–10, r = 0.36, p = 0.55; PM>10, r = −0.68, p = 0.21. Resazurin reduction. D) UFP, r = −0.19, p = 0.76; PM0.1–2.5, r = −0.63, p = 0.26; PM2.5–10, r = −0.60, p = 0.28; PM>10,r = 0.18, p = 0.78. Water-soluble metals. UFP, r = −0.20, p = 0.74; PM0.1–2.5, r = −0.41, p = 0.49; PM2.5–10, r = −0.09, p = 0.88; PM>10, r = 0.04, p = 0.95. Non-water-soluble metals. UFP, r = −0.12, p = 0.84; PM0.1–2.5, r = −0.65, p = 0.24; PM2.5–10, r = −0.62, p = 0.26; PM>10, r = 0.18, p = 0.77. (PDF 43 kb

Insights into Elemental Composition and Sources of Fine and Coarse Particulate Matter in Dense Traffic Areas in Toronto and Vancouver, Canada

Traffic is a significant pollution source in cities and has caused various health and environmental concerns worldwide. Therefore, an improved understanding of traffic impacts on particle concentrations and their components could help mitigate air pollution. In this study, the characteristics and sources of trace elements in PM2.5 (fine), and PM10-2.5 (coarse), were investigated in dense traffic areas in Toronto and Vancouver, Canada, from 2015–2017. At nearby urban background sites, 24-h integrated PM samples were also concurrently collected. The PM2.5 and PM10-2.5 masses, and a number of elements (i.e., Fe, Ba, Cu, Sb, Zn, Cr), showed clear increases at each near-road site, related to the traffic emissions resulting from resuspension and/or abrasion sources. The trace elements showed a clear partitioning trend between PM2.5 and PM10-2.5, thus reflecting the origin of some of these elements. The application of positive matrix factorization (PMF) to the combined fine and coarse metal data (86 total), with 24 observations at each site, was used to determine the contribution of different sources to the total metal concentrations in fine and coarse PM. Four major sources were identified by the PMF model, including two traffic non-exhaust (crustal/road dust, brake/tire wear) sources, along with regional and local industrial sources. Source apportionment indicated that the resuspended crustal/road dust factor was the dominant contributor to the total coarse-bound trace element (i.e., Fe, Ti, Ba, Cu, Zn, Sb, Cr) concentrations produced by vehicular exhaust and non-exhaust traffic-related processes that have been deposited onto the surface. The second non-exhaust factor related to brake/tire wear abrasion accounted for a considerable portion of the fine and coarse elemental (i.e., Ba, Fe, Cu, Zn, Sb) mass at both near-road sites. Regional and local industry contributed mostly to the fine elemental (i.e., S, As, Se, Cd, Pb) concentrations. Overall, the results show that non-exhaust traffic-related processes were major contributors to the various redox-active metal species (i.e., Fe, Cu) in both PM fractions. In addition, a substantial proportion of these metals in PM2.5 was water-soluble, which is an important contributor to the formation of reactive oxygen species and, thus, may lead to oxidative damage to cells in the human body. It appears that controlling traffic non-exhaust-related metals emissions, in the absence of significant point sources in the area, could have a pronounced effect on the redox activity of PM, with broad implications for the protection of public health

Effects of precipitation and UV photolysis on Ag isotope ratio: experimental studies

First results on silver isotope fractionation observed in a number of experimental studies that mimic natural environment conditions and/or processes are reported. Precipitation of Ag as AgCl in the presence of a small amount of Cl 12\ub9 induced significant isotopic fractionation. A \u3b4107/109Ag value of 120.17 \ub1 0.03\u2030 (1SD, n = 3) (relative to SRM 978a Ag isotopic standard) was obtained at a 96% loss of the original aqueous Ag. Thus, during the precipitation process, the supernatant is enriched in heavy 109Ag whereas AgCl precipitate is enriched in 107Ag. A slightly positive value of 0.052 \ub1 0.013 (1SD, n = 3) for \u3b4107/109Ag obtained in lake sediment samples collected from the St. George Lake (Ontario, Canada), wherein no industrial or domestic discharge is present, corroborates with results obtained during Cl 12\ub9 precipitation laboratory experiments. This observation suggests that the natural precipitation process in the presence of Cl 12\ub9 may be a major mechanism for the observed Ag isotope fractionation in uncontaminated lake sediments. The depletion of aqueous silver and its isotope fractionation during UV photolysis experiments were not significant. Only 12\u201325% of Ag was lost under test conditions, suggesting that the transport of Ag from the aquatic system to the atmosphere is rather limited in the natural environment. Physical mixing of a dietary Ag supplement, which has distinct isotopic composition, with sediment CRM PACS-2 was performed in order to investigate the possibility of tracking the origin of Ag through the use of its isotope ratio information. Isotope ratios of Ag measured in these mixtures gave a well-defined mixing pattern of these two end members. Results obtained in this study suggest that the Ag isotope ratio measured by MC-ICPMS may be a useful tracer for studying the natural processes and/or tracking the origin of the anthropogenic Ag in the environment.Peer reviewed: YesNRC publication: Ye

Chemical Characterization of Exhaust Emissions from Selected Canadian Marine Vessels: The Case of Trace Metals and Lanthanoids

This paper reports the chemical composition of exhaust emissions from the main engines of five ocean going cargo vessels, as they traveled in Canadian waters. The emission factors (EFs) of PM_2.5 and SO₂ for vessels tested on various intermediate fuel oils (IFO), ranged from 0.4 to 2.2 g kW^–1 hr^–1 and 4.7 to 10.3 g kW^–1 hr^–1, respectively, and were mainly dependent on the content of sulfur in the fuel. Average NO_<i>x</i>, CO, and CO₂ EFs for these tests were 12.7, 0.45, and 618 g kW^–1 hr^–1, respectively and were generally below benchmark values commonly used by regulatory agencies. The composition of PM_2.5 was dominated by hydrated sulfates, organic carbon and trace metals which accounted for 80–97% of total PM_2.5 mass. A substantial decrease of measured emission factors for PM_2.5 and SO₂ was observed when the fuel was changed from IFO to marine diesel oil (MDO), in one of the tested vessels. The main component of PM_2.5 in this case was organic carbon accounting for 65% of PM_2.5 mass. In addition to commonly reported pollutants, this study presents EFs of the lanthanoid elements and showed that their distribution patterns in ship-exhaust PM_2.5 were very similar to the PM_2.5 emitted by oil refining facilities. Hence, using La:Ce:V tertiary diagrams and La/V ratios is necessary to distinguish ship plumes from primary emissions related to accidental and/or routine operation of oil-refining industry

Accurate and precise determination of silver isotope fractionation in environmental samples by multicollector-ICPMS

High precision silver isotope ratios in environmental samples were determined by multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). Purification of Ag from sample matrixes was performed by a two stage tandem column setup with use of anion and cation exchange resin, sequentially. It was found that 1% HNO3 and 3% HCl was efficient to stabilize Ag in the final purified sample digests prior to MC-ICPMS determination. Pd at 2 \u3bcg g 121 was added to both sample and Ag standard solution as a common doping matrix as well as an internal standard for mass bias correction. Mass discrimination and instrument drift were corrected by a combination of internal normalization with Pd and standard-sample-standard bracketing, without assuming identical mass bias for Pd and Ag. NIST SRM 978a (silver isotopic standard reference material) was used for method validation and subjected to column separation and sample preparation processes. A value of 120.003 \ub1 0.010 \u2030 for \u3b4107/109Ag (mean and 2SD, n = 4) was obtained, confirming accurate results can be obtained using the proposed method. To the best of our knowledge, this is the first report on \u3b4107/109Ag variations in environmental samples. Significant differences in Ag isotope ratios were found among NIST SRM 978a standard, sediment CRM PACS-2, domestic sludge SRM 2781, industrial sludge 2782, and the fish liver CRM DOLT-4. The sediment CRM PACS-2 has a very small negative \u3b4107/109Ag value of 120.025 \ub1 0.012 \u2030 (2SD, n = 4). The domestic sludge SRM 2781 has a negative \u3b4107/109Ag value of 120.061 \ub1 0.010 \u2030 (2SD, n = 4), whereas industrial sludge SRM 2782 has a positive \u3b4107/109Ag value of +0.044 \ub1 0.014 \u2030 (2SD, n = 4), which may indicate the contribution of Ag from different anthropogenic inputs. DOLT-4 has a much larger negative value of 120.284 \ub1 0.014 \u2030 (2SD, n = 4), possibly caused by biological processes. These observations confirm that Ag isotope fractionation may provide a useful tool for fingerprinting sources of Ag in the environment and for studying a wide variety of chemical and biological processes in nature. High precision of better than \ub10.015 \u2030 (2SD, n = 4) obtained in real sample matrixes makes the present method well suited for monitoring small Ag isotope fractionation in nature.Des rapports isotopiques de haute pr\ue9cision de l\u2019argent dans des \ue9chantillons pr\ue9lev\ue9s dans l\u2019environnement sont obtenus par la spectrom\ue9trie de masse \ue0 source \ue0 plasma inductif et collection d\u2019ions multiples (MC-ICP-MS). Une purification de l\u2019Ag \ue0 partir de matrices de pr\ue9l\ue8vement est effectu\ue9e au moyen d\u2019un montage en tandem de deux colonnes; l\u2019une contenant un \ue9changeur d\u2019anions et l'autre, un \ue9changeur de cations. On constate que l\u2019utilisation de HNO3 \ue0 1 % et d\u2019HCL \ue0 3 % est efficace pour stabiliser l\u2019Ag dans les \ue9chantillons finaux dig\ue9r\ue9s et purifi\ue9s avant le dosage par la MC ICP-MS. On ajoute du Pd \ue0 une concentration de 2 \u3bcg g 121 aux deux \ue9chantillons et \ue0 la solution \ue9talon d\u2019Ag comme matrice de dopage commune, de m\ueame qu\u2019un \ue9talon interne pour la correction du biais massique. On a corrig\ue9 la discrimination de masse et la d\ue9rive de l\u2019instrument par la combinaison d\u2019une normalisation interne avec le Pd et d\u2019un encadrement \ue9talon-\ue9chantillon-\ue9talon, sans pr\ue9tendre une justesse de masse identique pour le Pd et l\u2019Ag. Le NIST SRM 978a (mat\ue9riau de r\ue9f\ue9rence \ue9talon d\u2019isotopes d\u2019argent) a \ue9t\ue9 utilis\ue9 pour valider la m\ue9thode et soumis aux processus de s\ue9paration par colonne et de pr\ue9paration d\u2019\ue9chantillons. On a obtenu une valeur \u3b4107/109Ag de 120,003 \ub1 0,010 \u2030 (moyenne et 2ET, n = 4), confirmant qu\u2019il est possible d\u2019obtenir des r\ue9sultats pr\ue9cis au moyen de la m\ue9thode propos\ue9e. Autant que nous sachions, c\u2019est la premi\ue8re fois que l\u2019on fait \ue9tat des variations de \u3b4107/109Ag dans des \ue9chantillons pr\ue9lev\ue9s dans l\u2019environnement. Nous avons constat\ue9 des diff\ue9rences importantes dans les rapports isotopiques de l\u2019Ag entre l\u2019\ue9talon NIST SRM 978a, le s\ue9diment CRM PACS-2, la boue domestique SRM 2781, la boue industrielle SRM 2782 et le foie de poisson CRM DOLT-4. Le s\ue9diment CRM PACS-2 poss\ue8de une tr\ue8s petite valeur \u3b4107/109Ag n\ue9gative de 120,025 \ub1 0,012 \u2030 (2ET, n = 4). La boue domestique SRM 2781 poss\ue8de une valeur \u3b4107/109Ag n\ue9gative de 120,061 \ub1 0,010 \u2030 (2ET, n = 4), alors que la boue industrielle SRM 2782 poss\ue8de une valeur \u3b4107/109Ag positive de +0,044 \ub1 0,014 \u2030 (2ET, n = 4), ce qui peut indiquer la contribution de l\u2019Ag provenant de diff\ue9rents apports anthropiques. Le DOLT-4 a une valeur n\ue9gative beaucoup plus importante de 120,284 \ub1 0,014 \u2030 (2ET, n = 4), probablement attribuable \ue0 des processus biologiques. Ces observations confirment que le fractionnement des isotopes de l\u2019Ag peut constituer un outil utile pour caract\ue9riser des sources d\u2019Ag dans l\u2019environnement et \ue9tudier une grande vari\ue9t\ue9 de processus chimiques et biologiques dans la nature. La haute pr\ue9cision sup\ue9rieure \ue0 \ub10,015 \u2030 (2ET, n = 4) obtenue dans des matrices de pr\ue9l\ue8vement r\ue9elles rend la pr\ue9sente m\ue9thode bien adapt\ue9e au suivi du faible fractionnement isotopique de l\u2019Ag dans la nature.Peer reviewed: YesNRC publication: Ye

Effect of industrialization on the differences in sources and composition of ambient PM in two Southern Ontario locations.

PM2.5 was sampled over a seven-year period (2013-2019) at two locations ∼50 km apart in Southern Ontario (concurrently for five years: 2015-2019). One is a heavily industrialized site (Hamilton), while the other was a rural site (Simcoe). To assess the impact of industrialization on the composition and sources of PM affecting air quality in these two locations, positive matrix factorization coupled with dispersion normalization (DN-PMF) was used to identify six and eight factors at Simcoe and Hamilton, respectively. The Simcoe factors in order of diminishing PM mass contribution were: particulate sulphate (pSO4), secondary organic aerosol (SOA), crustal matter, particulate nitrate (pNO3), biomass burning, and vehicular emissions. At Hamilton, the effects of industrialization were observed by the ∼36% higher average ambient PM2.5 concentration for the study period as well as the presence of factors unique to metallurgy, i.e., coking and steelmaking, compared to Simcoe. The coking and steelmaking factors contributed ∼15% to the PM mass at Hamilton. Seasonal variants of appropriate nonparametric trend tests with the associated slopes (Sen's) were used to assess statistically significant changes in the factor contributions to PM2.5 over time. Specifically at Hamilton, a significant decline in PM contributions was noted for coking (-0.03 μg/m³/yr or -4.1%/yr) while steelmaking showed no statistically significant decline over the study period. Other factors at Hamilton that showed statistically significant declines over the study period were: pSO4 (-0.27 μg/m³/yr or -12.6%/yr), biomass burning (-0.05 μg/m³/yr or -9.02%/yr), crustal matter (-0.03 μg/m³/yr or -5.28%/yr). These factors mainly accounted for the significant decline in PM2.5 over the study period (-0.35 μg/m³/yr or -4.24%/yr). This work shows the importance of long-term monitoring in assessing the unique contributions and temporal changes of industrialization on air quality in Ontario and similarly affected locations

Sources of particulate matter components in the Athabasca oil sands region: investigation through a comparison of trace element measurement methodologies

The province of Alberta, Canada, is home to three oil sands regions which, combined, contain the third largest deposit of oil in the world. Of these, the Athabasca oil sands region is the largest. As part of Environment and Climate Change Canada's program in support of the Joint Canada-Alberta Implementation Plan for Oil Sands Monitoring program, concentrations of trace elements in PM2. 5 (particulate matter smaller than 2.5 µm in diameter) were measured through two campaigns that involved different methodologies: a long-term filter campaign and a short-term intensive campaign. In the long-term campaign, 24 h filter samples were collected once every 6 days over a 2-year period (December 2010–November 2012) at three air monitoring stations in the regional municipality of Wood Buffalo. For the intensive campaign (August 2013), hourly measurements were made with an online instrument at one air monitoring station; daily filter samples were also collected. The hourly and 24 h filter data were analyzed individually using positive matrix factorization. Seven emission sources of PM2. 5 trace elements were thereby identified: two types of upgrader emissions, soil, haul road dust, biomass burning, and two sources of mixed origin. The upgrader emissions, soil, and haul road dust sources were identified through both the methodologies and both methodologies identified a mixed source, but these exhibited more differences than similarities. The second upgrader emissions and biomass burning sources were only resolved by the hourly and filter methodologies, respectively. The similarity of the receptor modeling results from the two methodologies provided reassurance as to the identity of the sources. Overall, much of the PM2. 5-related trace elements were found to be anthropogenic, or at least to be aerosolized through anthropogenic activities. These emissions may in part explain the previously reported higher levels of trace elements in snow, water, and biota samples collected near the oil sands operations.This study was undertaken with the financial and operational support of the Government of Canada through Environment and Climate Change Canada as part of the Joint Canada-Alberta Implementation Plan for Oil Sands Monitoring program. Infrastructure support was provided by the Canada Foundation for Innovation and the Ontario Research Fund (Project: 19606). The authors thank the Wood Buffalo Environmental Association (WBEA) for support in integrated air sampling collection in the Athabasca oil sands region. We would like also to acknowledge the provincial, territorial, and municipal governments as partners of the National Air Pollution Surveillance (NAPS) Program