Abstract
A pilot study was initiated in 2018 under the Global Atmospheric Passive Sampling (GAPS) Network named GAPS-Megacities. This study included 20 megacities/major cities across the globe with the goal of better understanding and comparing ambient air levels of persistent organic pollutants and other chemicals of emerging concern, to which humans residing in large cities are exposed. The first results from the initial period of sampling are reported for 19 cities for several classes of flame retardants (FRs) including organophosphate esters (OPEs), polybrominated diphenyl ethers (PBDEs), and halogenated flame retardants (HFRs) including new flame retardants (NFRs), tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDD). The two cities, New York (USA) and London (UK) stood out with ∼3.5 to 30 times higher total FR concentrations as compared to other major cities, with total concentrations of OPEs of 15,100 and 14,100 pg/m3, respectively. Atmospheric concentrations of OPEs significantly dominated the FR profile at all sites, with total concentrations in air that were 2–5 orders of magnitude higher compared to other targeted chemical classes. A moderately strong and significant correlation (r = 0.625, p < 0.001) was observed for Gross Domestic Product index of the cities with total OPEs levels. Although large differences in FR levels were observed between some cities, when averaged across the five United Nations regions, the FR classes were more evenly distributed and varied by less than a factor of five. Results for Toronto, which is a ‘reference city’ for this study, agreed well with a more in-depth investigation of the level of FRs over different seasons and across eight sites representing different urban source sectors (e.g. traffic, industrial, residential and background). Future sampling periods under this project will investigate trace metals and other contaminant classes, linkages to toxicology, non-targeted analysis, and eventually temporal trends. The study provides a unique urban platform for evaluating global exposome.
Highlights
Urban and metropolitan areas across the globe are home to 4.2 billion people, constituting 55% of the world’s total population (United Nations, 2018)
The total atmospheric concentrations of flame retardants (FRs) ranged from 500 pg/m3 to 16,000 pg/m3, with organophosphate esters (OPEs) dominating the profile at each city
This study highlights the importance of ambient air surveillance in urban areas to depict the changes in emission patterns and eventually temporal trends, in order to assess the effectiveness of imposed regulations under international treaties such as the Stockholm Convention
Summary
Urban and metropolitan areas across the globe are home to 4.2 billion people, constituting 55% of the world’s total population (United Nations, 2018). We hypothesize that in large megacities, persistent organic pollutants (POPs), the ones associated with particles present in the air, contribute significantly to the chemical burden and the toxicity of PM and the air mixture. There is previously established evidence as well as growing literature based on in vitro and in vivo studies, showing adverse health effects caused by the exposure to old and new POPs and POPs-like chemicals (Loganathan and Masunaga, 2009; Kim et al, 2013; Lyche et al, 2015; Abdel-Shafy and Mansour, 2016; Lam et al, 2017; Guigueno et al, 2019; Blum et al, 2019) and the importance of considering chemical mixtures in air (Escher et al, 2020)
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