Seasonal Changes in the Oxidative Potential of Urban Air Pollutants: The Influence of Emission Sources and Proton- and Ligand-Mediated Dissolution of Transition Metals.

The inhalation of fine particulate matter (PM) is a major contributor to adverse health effects from air pollution worldwide. An important toxicity pathway is thought to follow oxidative stress from the formation of exogenous reactive oxygen species (ROS) in the body, a proxy of which is oxidative potential (OP). As redox-active transition metals and organic species are important drivers of OP in urban environments, we investigate how seasonal changes in emission sources, aerosol chemical composition, acidity, and metal dissolution influence OP dynamics.

Oil sands process-affected water composition effect on Henry's law constants for polycyclic aromatic compounds: Theory and experiment.

Oil sands process-affected water (OSPW) is a source of atmospheric emission for polycyclic aromatic compounds (PACs), compounds known to have toxic effects on humans. Estimating emissions and assessing the chemical fate of PACs requires measured or predicted physical-chemical properties such as Henry's law constants (H), that can be used to predict chemical transfer into the atmosphere. OSPW is a complex water-based mixture that is highly variable in composition and nature and contains both organic and inorganic ions.

Informal E -waste recycling in nine cities of Pakistan reveals significant impacts on local air and soil quality and associated health risks.

The global increase in electronic waste (e-waste) has led to a rise in informal recycling, emitting hazardous heavy metals (HMs) that threaten human health and ecosystems. This study presents the first comprehensive assessment of HM levels in dry deposition and soils at proximity of forty (40) informal e-waste recycling sites across Pakistan, between September 2020 to December 2021. Findings reveal that Zn (1410), Pb (410) and Mn (231) exhibited the higher mean deposition fluxes (μg/m.

A method for measuring the bioaccessibility of polycyclic aromatic hydrocarbons in cell culture media.

Airborne polycyclic aromatic hydrocarbons (PAHs) and their derivatives are of particular concern for population health due to their abundance and toxicity via inhalation. Lung toxicity testing includes exposing lung epithelial cell lines to PAHs in a culture medium containing inorganic species, lipids, proteins, and other biochemicals where the cell response is influenced among others by the toxic chemical accessibility in the medium. While inhalation bioaccessibility of PAHs and other toxicants was previously studied in surrogate lung fluids, studies measuring bioaccessibility in cell culture media are rare.

Atmospheric emissions estimation of polycyclic aromatic compounds from an oil sands tailings pond using passive air samplers.

A mapping study targeting emissions of polycyclic aromatic compounds (PACs) from an oil sands tailings pond was undertaken in the Athabasca Oil sands Region (AOSR). Ten passive air samplers comprising polyurethane foam (PUF) disks were deployed around the perimeter of Suncor Tailings Pond 2/3 for a five-week period to generate time-integrated concentrations in air for PACs, which included ∑unsubstituted polycyclic aromatic hydrocarbons (PAHs), ∑alkylated PAHs (alk-PAHs), and ∑dibenzothiophenes (DBTs) (both unsubstituted and alkylated). Concentrations in air ranged from 13 to 70, 220-970, and 30-210 ng/m, respectively, and were elevated in samplers downwind of the tailings pond.

Impacts of Proximity to Primary Source Areas on Concentrations of POPs at Global Sampling Stations Estimated from Land Cover Information.

Given the considerable financial and logistical resources supporting long-term monitoring for air pollutants, and the use of these data for performance evaluation of mitigation measures, it is important to account for contributions from primary versus secondary sources. We demonstrate a simple approach for using open source Global land cover raster data from the National Mapping Organization from the Geospatial Information Authority of Japan to assess local source inputs for air measurements of legacy persistent organic pollutants (POPs)-polychlorinated biphenyls (PCBs) and organochlorine pesticides-reported under the Global atmospheric passive sampling (GAPS) Network at 119 locations for the time period 2005-2014. The land cover composition within a 10 km radius around the GAPS sites was identified to create source impact indicator (SII) vectors to quantify and rank the remoteness of the sites from human infrastructure.

Trace Metals in Global Air: First Results from the GAPS and GAPS Megacities Networks.

Trace metals, as constituents of ambient air, can have impacts on human and environmental health. The Global Atmospheric Passive Sampling (GAPS) and GAPS Megacities (GAPS-MC) networks investigated trace metals in the air at 51 global locations by deploying polyurethane foam disk passive air samplers (PUF-PAS) for periods of 3-12 months. Aluminum and iron exhibited the highest concentrations in air ( = 3400 and 4630 ng/m, respectively), with notably elevated values at a rural site in Argentina thought to be impacted by resuspended soil.

Developing Methods for Assessing Trophic Magnification of Perfluoroalkyl Substances within an Urban Terrestrial Avian Food Web.

We investigated the trophic magnification potential of perfluoroalkyl substances (PFAS) in a terrestrial food web by using a chemical activity-based approach, which involved normalizing concentrations of PFAS in biota to their relative biochemical composition in order to provide a thermodynamically accurate basis for comparing concentrations of PFAS in biota. Samples of hawk eggs, songbird tissues, and invertebrates were collected and analyzed for concentrations of 18 perfluoroalkyl acids (PFAAs) and for polar lipid, neutral lipid, total protein, albumin, and water content. Estimated mass fractions of PFCA C-C and PFSA C-C predominantly occurred in albumin within biota samples from the food web with smaller estimated fractions in polar lipids > structural proteins > neutral lipids and insignificant amounts in water.

Per- and polyfluoroalkyl substances and volatile methyl siloxanes in global air: Spatial and temporal trends.

The study reports on the atmospheric concentrations of per- and polyfluoroalkyl substances (PFAS) and volatile methyl siloxanes (VMS) measured using sorbent-impregnated polyurethane foam disks (SIPs) passive air samplers. New results are reported for samples collected in 2017, which extends temporal trend information to the period 2009-2017, for 21 sites where SIPs have been deployed since 2009. Among neutral PFAS, fluorotelomer alcohols (FTOHs) had higher concentrations than perfluoroalkane sulfonamides (FOSAs) and perfluoroalkane sulfonamido ethanols (FOSEs) with levels of ND‒228, ND‒15.

Air monitoring of tire-derived chemicals in global megacities using passive samplers.

Pollution from vehicle tires has received world-wide research attention due to its ubiquity and toxicity. In this study, we measured various tire-derived contaminants semi-quantitatively in archived extracts of passive air samplers deployed in 18 major cities that comprise the Global Atmospheric Passive Sampling (GAPS) Network (GAPS-Megacities). Analysis was done on archived samples, which represent one-time weighted passive air samples from each of the 18 monitoring sites.

Medium- and long-chain chlorinated paraffins in air: A review of levels, physicochemical properties, and analytical considerations.

Chlorinated paraffins (CPs) are synthetic chemicals that are produced at high volumes and have a global presence. CPs are generally divided into three groups based on their carbon chain lengths: short-chain CPs (SCCPs, C), medium-chain CPs (MCCPs, C), and long-chain CPs (LCCPs, C). SCCPs have been formally recognized as persistent organic pollutants (POPs) and have been listed under the Stockholm Convention on POPs.

A new method for measuring airborne elemental carbon using PUF disk passive samplers.

Carbonaceous aerosol species, such as elemental carbon (EC), are important Short-Lived Climate Forcers (SLCFs), contributing to climate and health effects of air pollution. The quantification of carbonaceous aerosols has been conventionally carried out using active air sampling followed by various analytical techniques, such as thermal/thermal-optical analysis. Active sampling requires specific equipment and infrastructure with electricity and therefore may not be the best choice for studying carbonaceous aerosols at remote locations.

Enhancing Scientific Support for the Stockholm Convention's Implementation: An Analysis of Policy Needs for Scientific Evidence.

The Stockholm Convention is key to addressing the global threats of persistent organic pollutants (POPs) to humanity and the environment. It has been successful in identifying new POPs, but its national implementation remains challenging, particularly by low- and middle-income Parties. Concerted action is needed to assist Parties in implementing the Convention's obligations.

Cytotoxic and Transcriptomic Effects in Avian Hepatocytes Exposed to a Complex Mixture from Air Samples, and Their Relation to the Organic Flame Retardant Signature.

Assessing complex environmental mixtures and their effects is challenging. In this study, we evaluate the utility of an avian in vitro screening approach to determine the effects of passive air sampler extracts collected from different global megacities on cytotoxicity and gene expression. Concentrations of a suite of organic flame retardants (OFRs) were quantified in extracts from a total of 19 megacities/major cities in an earlier study, and levels were highly variable across sites.

Uncovering global-scale risks from commercial chemicals in air.

Commercial chemicals are used extensively across urban centres worldwide, posing a potential exposure risk to 4.2 billion people. Harmful chemicals are often assessed on the basis of their environmental persistence, accumulation in biological organisms and toxic properties, under international and national initiatives such as the Stockholm Convention.

Global intercomparison of polyurethane foam passive air samplers evaluating sources of variability in SVOC measurements.

Polyurethane foam passive air samplers (PUF-PAS) are the most common type of passive air sampler used for a range of semi-volatile organic compounds (SVOCs), including regulated persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs), and emerging contaminants (e.g., novel flame retardants, phthalates, current-use pesticides).

Fugacity-Based Trophic Magnification Factors Characterize Bioaccumulation of Cyclic Methyl Siloxanes within an Urban Terrestrial Avian Food Web: Importance of Organism Body Temperature and Composition.

Trophic magnification of cyclic volatile methyl siloxanes (cVMS) in a terrestrial food web was investigated by measuring concentrations of octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) and two reference chemicals within air and biota samples from an avian food web located in a mixed urban-agricultural landscape. Terrestrial trophic magnification factors derived from lipid normalized concentrations (TMFs) for D5 and D6 were 0.94 (0.

Guidance on the Application of Polyurethane Foam Disk Passive Air Samplers for Measuring Nonane and Short-Chain Chlorinated Paraffins in Air: Results from a Screening Study in Urban Air.

This study provides guidance on using polyurethane foam-based passive air samplers (PUF-PASs) for atmospheric nonane chlorinated paraffins (C-CPs) and short-chain CPs (SCCPs) and reports SCCP concentrations in air in the Greater Toronto Area (GTA), Canada. We estimated the partition coefficients between PUF and air () and between octanol and air () for C-CP and SCCP congeners using the COSMO-RS method, so that PUF disk uptake profiles for each formula group could be calculated. We then measured SCCP concentrations in PUF disk samples collected from distinct source sectors in urban air across the GTA.

Bisphenol A and its analogues in outdoor and indoor air: Properties, sources and global levels.

Bisphenol A (BPA) and its analogues are high-volume production organic synthetic compounds used in the synthesis of plastics. BPA has been categorized as an endocrine disrupting compound due to its ability to disrupt the hormonal makeup of living organisms. Air and dust are common sources of exposure of BPA for living organisms and most sources are anthropogenic and a result of thermal destruction of BPA containing materials, import and export of recyclable materials (especially e-waste) and fugitive emissions near BPA handling facilities.

Tracking POPs in Global Air from the First 10 Years of the GAPS Network (2005 to 2014).

The Global Atmospheric Passive Sampling (GAPS) network, initiated in 2005 across 55 global sites, supports the global monitoring plan (GMP) of the Stockholm Convention on Persistent Organic Pollutants (POPs) by providing information on POP concentrations in air on a global scale. These data inform assessments of the long-range transport potential of POPs and the effectiveness evaluation of chemical regulation efforts, by observing changes in concentrations over time. Currently, measurements spanning 5-10 sampling years are available for 40 sites from the GAPS Network.

Insights into sources and occurrence of oxy- and nitro-PAHs in the alberta oil sands region using a network of passive air samplers.

Mining-related activities in the Alberta Oil Sands Region (AOSR) are known to emit polycyclic aromatic hydrocarbons (PAHs) and related compounds to ambient air. This is a concern due to the toxicity of PAHs, including their transformation products such as nitrated (NPAHs) and oxygenated (OPAHs) PAHs. This is the first study that provided a more extensive outlook into the sources, occurrence in air, and spatial and seasonal patterns of NPAHs and OPAHs in the AOSR by using passive air sampling.

The effects of plume episodes on PAC profiles in the athabasca oil sands region.

Summer intensive air measurements of alkylated polycyclic aromatic compounds (Alk-PACs), nitrated polycyclic aromatic hydrocarbons (NPAHs), and oxygenated polycyclic aromatic hydrocarbons (OPAHs) was conducted during the summer of 2013 at an air monitoring site near the community of Fort McKay in the Athabasca oil sands region (AOSR). This study uses the ambient air measurements in conjunction with supplementary meteorological and air quality data from coordinated ground- and aircraft-based sampling over the same period to characterize diurnal variations and changes in the organic air pollutant profiles associated with the plume episodes. Principal component analysis showed a distinct PAC profile during plume episodes, driven mainly by higher fluorenone (FLO) and 9,10-anthraquinone (ANQ) concentrations.

The influence of chemical composition, aerosol acidity, and metal dissolution on the oxidative potential of fine particulate matter and redox potential of the lung lining fluid.

Air pollution is a major environmental health risk and it contributes to respiratory and cardiovascular diseases and excess mortality worldwide. The adverse health effects have been associated with the inhalation of fine particulate matter (PM) and induction of respiratory oxidative stress. In this work, we quantified the oxidative potential (OP) of PM from several Canadian cities (Toronto, Hamilton, Montreal, Vancouver) using a recently developed bioanalytical method which measures the oxidation of lung antioxidants, glutathione, cysteine, and ascorbic acid, the formation of glutathione disulfide and cystine, and the related redox potential (RP) in a simulated epithelial lining fluid (SELF).