quality of life
Lockdown measures in response to the new Covid-19 virus have caused the largest ever fall of annual greenhouse gas emissions. A key question that we attempt to answer in this study is which, if any, of these measures can be productively encouraged post-lockdown in efforts to sustain at least part of this reduction in emissions. Sweden is uniquely suited for our study because the voluntary nature of lockdown in Sweden allowed us to assess the level of compliance to recommendations and its effects on greenhouse gas emissions. First, we assessed the change of perceived quality of life (QOL) among 746 individuals from Stockholm region due to adhering to lockdown measures. Second, we calculated the associated change of annual per capita greenhouse emissions. We found that avoiding travel for work, avoiding purchasing, and avoiding restaurants had the least negative effect on QOL, and at the same time the largest positive effect on carbon dioxide equivalent (CO(2)e) emission reductions. We conclude that these are potential leverage points for stimulating behavioral change that has a positive climatic impact.
Degradation of naturally produced hydroxylated polybrominated diphenyl ethers in Baltic Sea sediment via reductive debromination
Over the last two decades, the occurrence of hydroxylated polybrominated diphenyl ethers (OH-PBDEs) has been observed to be nearly ubiquitous among Baltic Sea filamentous macroalgae. High concentrations are continuously recorded among red, green, and brown filamentous algae. Several of these algae species are ephemeral, and when large parts of the colonies decay at the end of their lifecycles, the OH-PBDEs are expected to largely partition to the sediment. In this study, the fate of OH-PBDEs in Baltic Sea sediment was investigated, with focus on the effect of reductive debromination. During chemical debromination, it was observed that the half-life could differ with as much as two orders of magnitude between a pentabrominated and a tetrabrominated congener. Using collected Baltic Sea sediment, it was further observed that the half-life of spiked pentabrominated OH-PBDEs spanned from a few days up to a few weeks in room temperature. At 4 degrees C, it took 6 months to achieve a 50% decrease in concentration of the fasted degrading congener. Clear differences in selectivity between chemical debromination and debromination in sediment were also observed when studying the major reaction products. Baltic Sea sediment seems to have a good capacity for reducing naturally produced OH-PBDEs.
Mechanistic Investigation of Dimethylmercury Formation Mediated by a Sulfide Mineral Surface
Mercury (Hg) pollution is a global environmental problem. The abiotic formation of dimethylmercury (DMeHg) from monomethylmercury (MMeHg) may account for a large portion of DMeHg in oceans. Previous experimental work has shown that abiotic formation of DMeHg from MMeHg can be facilitated by reduced sulfur groups on sulfide mineral surfaces. In that work, a mechanism was proposed in which neighboring MMeHg moieties bound to sulfide sites on a mineral surface react through an S(N)2-type mechanism to form DMeHg and incorporate the remaining Hg atoms into the mineral surface. Here, we perform density functional theory calculations to explore the mechanisms of DMeHg formation on the 110 surface of a CdS(s) (hawleyite) nanoparticle. We show that coordination of MMeHg substituents to adjacent reduced sulfur groups protruding from the surface indeed facilitates DMeHg formation and that the reaction proceeds through direct transmethylation from one MMeHg substituent to another. Coordination of Hg by multiple S atoms provides a transition-state stabilization and activates a C-Hg bond for methyl transfer. In addition, solvation effects play an important role in the surface reconstruction of the nanoparticle and in decreasing the energetic barrier for DMeHg formation relative to the corresponding reaction in vacuo.
Permafrost Thaw Increases Methylmercury Formation in Subarctic Fennoscandia
Tarbier, B; Hugelius, G; Sannel, ABK; Baptista-Salazar, C; Jonsson, S
Methylmercury (MeHg) forms in anoxic environments and can bioaccumulate and biomagnify in aquatic food webs to concentrations of concern for human and wildlife health. Mercury (Hg) pollution in the Arctic environment may worsen as these areas warm and Hg, currently locked in permafrost soils, is remobilized. One of the main concerns is the development of Hg methylation hotspots in the terrestrial environment due to thermokarst formation. The extent to which net methylation of Hg is enhanced upon thaw is, however, largely unknown. Here, we have studied the formation of Hg methylation hotspots using existing thaw gradients at five Fennoscandian permafrost peatland sites. Total Hg (HgT) and MeHg concentrations were analyzed in 178 soil samples from 14 peat cores. We observed 10 times higher concentrations of MeHg and 13 times higher %MeHg in the collapse fen (representing thawed conditions) as compared to the peat plateau (representing frozen conditions). This suggests significantly greater net methylation of Hg when thermokarst wetlands are formed. In addition, we report HgT to soil organic carbon ratios representative of Fennoscandian permafrost peatlands (median and interquartile range of 0.09 +/- 0.07 mu g HgT g(-1) C) that are of value for future estimates of circumpolar HgT stocks.
Elevated concentrations of mercury and methylmercury in the Gadani shipbreaking area, Pakistan
Gadani shipbreaking area, Pakistan, is the world's third largest shipbreaking unit. However, to date, only a few studies on the environmental impacts of the industry, including mercury (Hg) pollution, have been conducted. To address this, concentrations of total Hg (HgT) and methylmercury (MeHg) were measured in surface sediments collected from the Gadani shipbreaking area as well as a local reference area. The highest concentrations of HgT and MeHg (median +/- interquartile range) were detected in samples from the beach at the yard zone (HgT: 270 +/- 230 mu g kg(-1), MeHg: 0.65 +/- 0.69 mu g kg(-1)), followed by sediment samples from the inter/sub-tidal zone where ships are dismantled (HgT: 20 +/- 5.8 mu g kg(-1), MeHg: 0.043 +/- 0.016 mu g kg(-1)). These concentrations were on average 4-50 and 3-30 times greater than the concentrations of HgT and MeHg, respectively, observed in the reference area. Capsule: Elevated concentrations of total and methylated mercury observed in the Gadani Shipbreaking area sediments.
When science and politics come together: From depletion to recovery of the stratospheric ozone hole This article belongs to Ambio’s 50th Anniversary Collection. Theme: Ozone Layer
Differing Mechanisms of New Particle Formation at Two Arctic Sites
Lisa J. Beck; Nina Sarnela; Heikki Junninen; Clara J. M. Hoppe; Olga Garmash; Federico Bianchi; Matthieu Riva; Clemence Rose; Otso Peräkylä; Daniela Wimmer; Oskari Kausiala; Tuija Jokinen; Lauri Ahonen; Jyri Mikkilä; Jani Hakala; Xu‐Cheng He; Jenni Kontkanen; Klara K. E. Wolf; David Cappelletti; Mauro Mazzola; Rita Traversi; Chiara Petroselli; Angelo P. Viola; Vito Vitale; Robert Lange; Andreas Massling; Jakob K. Nøjgaard; Radovan Krejci; Linn Karlsson; Paul Zieger; Sehyun Jang; Kitack Lee; Ville Vakkari; Janne Lampilahti; Roseline C. Thakur; Katri Leino; Juha Kangasluoma; Ella‐Maria Duplissy; Erkki Siivola; Marjan Marbouti; Yee Jun Tham; Alfonso Saiz‐Lopez; Tuukka Petäjä; Mikael Ehn; Douglas R. Worsnop; Henrik Skov; Markku Kulmala; Veli‐Matti Kerminen; Mikko Sipilä
| Geophys Res Lett
New particle formation in the Arctic atmosphere is an important source of aerosol particles. Understanding the processes of Arctic secondary aerosol formation is crucial due to their significant impact on cloud properties and therefore Arctic amplification. We observed the molecular formation of new particles from low‐volatility vapors at two Arctic sites with differing surroundings. In Svalbard, sulfuric acid (SA) and methane sulfonic acid (MSA) contribute to the formation of secondary aerosol and to some extent to cloud condensation nuclei (CCN). This occurs via ion‐induced nucleation of SA and NH3 and subsequent growth by mainly SA and MSA condensation during springtime and highly oxygenated organic molecules during summertime. By contrast, in an ice‐covered region around Villum, we observed new particle formation driven by iodic acid but its concentration was insufficient to grow nucleated particles to CCN sizes. Our results provide new insight about sources and precursors of Arctic secondary aerosol particles.