Passive air sampling (PAS) was used to evaluate organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), hexabromocyclododecanes (HBCDDs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and per- and polyfluoroalkyl substances (PFASs) in the atmosphere of Medellin, Colombia. This was in accordance with a special initiative of the Global Monitoring Plan (GMP), which was implemented to provide information on new and emerging persistent organic pollutants (POPs).PAS was carried out for three months (four quartiles per year) over two consecutive years (2017 and 2018), and two punctual peaks of contamination in the monitored time were observed. The first peak was related to chlorinated compounds in the quartile 2017-Q3, in which the highest concentration of pentachlorobenzene (PeCB, 755.5 pg·m-3) was observed, and air concentration of PeCB in quartile 2018-Q4 (125.0 pg·m-3) was 3.7 times more than the initial concentration (33.7 pg·m-3). These results may be associated with waste incineration in or near the city. The second peak of contamination was associated with brominated compounds in the quartile 2018-Q1, which could be linked to recycling, incineration, and landfill deposit of these compounds. In this peak, the highest levels of PBDEs and HBCDD-isomers were observed (Σ10PBDEs, 107.2 pg·m-3 and Σ3HBCDDs-isomers, 289.0 pg·m-3). With regard to the concentrations of PBDEs, HBCDDs, PCDDs, and PCDFs, these showed a slight tendency to increase between 2017 and 2018. Finally, constants concentrations of pollutants such as DDT isomers and dieldrin were observed, although these compounds were banned in Colombia many years ago. In contrast, a slight decrease in some pollutants, such as aldrin, and α-endosulfan, was observed.Our study allowed the assessment of air levels of chlorinated, brominated, and fluorinated pollutants in Medellin, Colombia. These results provide an overall view of POPs levels and represent an initial attempt to identify local sources in order to monitor and surveillance the releases of these pollutants in the city and country.

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Emissions from the oil and gas sector are important for climate change, ozone production and human health. Oil and gas leakage rates reported in the United States (US), estimated by relating measured methane fluxes with natural gas production, vary from less than 1% (e.g. Upper Green River Basin, (UGRB) in Wyoming) to over 6% (Uintah Basin, Utah). We demonstrate the applicability of the Pocket Diffusive (POD) sampler for scoping assessments of levels hydrocarbons and volatile polycyclic aromatic hydrocarbons (PAH) in areas heavily influenced by existing O&G development. We assess three US basins (Upper Green River, Uintah, and North Platte River), each with different characteristics, most importantly meteorology and emissions, which influence measured air quality. We contrast ambient concentrations of hydrocarbons (C4-C 12 ) and volatile PAHs at these basins and show important differences between measured levels of pollutants, including benzene. Our POD sampling results support previous findings of relatively elevated levels of aromatics in the Pinedale Anticline (UGRB) and relatively high alkane concentrations in the Uintah Basin. Concentrations of alkenes and PAH shows that these compound classes are at relatively low levels, and as such are of less concern in the assessed basins.