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Since black carbon (BC) has become one of the most harmful pollutants and partly accelerated the melting of the Arctic sea ice, internationally mandatory policy to limit black carbon emissions in the whole Polar Code Area is on the agenda. To cope with this policy, some potential measures from both the coastal government and the shipowners, as well as the economic impacts of these measures, are considered in this paper. We analyze the daily navigation profits and the corresponding BC emissions after these measures are adopted. Since equipment-related cost is usually regarded as fixed and cannot be calculated on a daily basis, this paper also proposes an equipment investment payback period to access the time needed to achieve a balance between the investments and the profits of applying the equipment. A case of a dry bulk carrier navigating through the Northwest Passage is presented for concrete quantitative analysis. The results indicate that wind propulsion system can help shipowners mitigate the largest amount of BC emission. Wind-driven generators, which are used for auxiliary generating system, are the most economic-beneficial to shipowners under the current technology environment. Besides, we found that BC emission tax rate set by coastal governments plays an important role in the selection of different measures by shipowners. [ABSTRACT FROM AUTHOR]

The circum-Arctic region experienced serious fires in 2019 and 2020. Biomass burning is considered a primary source of black carbon (BC) aerosols. BC contributes to Arctic warming and impacts snow/ice melting. However, the impacts of biomass burning on BC in the Arctic during these recent serious fires have not been quantified in detail. In this study, based on numerical simulations using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), we calculated the contribution ratios of biomass burning to Arctic BC and revealed its transport pathways. Affected by biomass burning emissions, the near-surface BC concentrations over the terrestrial areas within the Arctic Circle were highest in summer, and declined in spring and autumn. Spatially, high-concentration levels of BC were distributed in the Russian central and eastern areas. Biomass burning accounted for 63.72% and 45.18% of the summer BC in the Arctic near-surface and middle troposphere, respectively. In the near-surface, the contributions from local Arctic sources were comparable to those from sources outside the Arctic Circle in summer. In the middle troposphere, contributions from sources outside the Arctic Circle were dominant. In summer, BC originating from biomass burning in Siberia was transported a short distance by southwesterly winds to the central Arctic near-surface, while the enhanced southwesterly winds in the middle troposphere transported BC from Siberia, Alaska and northern Canada to the central Arctic and Greenland. In spring and autumn, most BC originating from biomass burning in the near-surface of Eurasia was transported eastward by westerly winds and then transported northward over the North Pacific Ocean, and the long distance may have resulted in fewer effects on the Arctic. These results highlight the important role of biomass burning in the Arctic environment under a warming climate. [Display omitted] • Affected by biomass burning, the near-surface BC concentrations over the terrestrial areas within the Arctic Circle were highest in summer. • The biomass burning contributions from local sources to Arctic BC in the near-surface in summer were obvious. • BC from biomass burning in the near-surface of Siberia were transported by southwesterly winds to the central Arctic. • The enhanced southwesterly winds in the middle troposphere transported BC from Siberia, Alaska, and northern Canada to the central Arctic and Greenland. [ABSTRACT FROM AUTHOR]

The outbreak of SARS-CoV-2 and subsequent spread of the disease COVID-19 became classified as a pandemic in March of 2020, leading to global safety measures introduced to limit the impact of the virus. This combination of safety measures has become commonly referred to as "lockdown". The associated industry and lifestyle changes led to reductions in the anthropogenic emission of atmospheric pollutants such as black carbon (BC), which is transported from the mid-latitudes into the Arctic during the winter and spring. Measurements of BC and other anthropogenic pollutants are of increasing importance in the Arctic due to the rapid warming observed there in the past few decades. It is believed that BC has a significant role in this warming, and so understanding the Arctic's response to reduced BC emissions at lower latitudes will provide insight into how future changes might mitigate further warming. Reductions in BC have been reported worldwide, and so in this study, the impact of these reductions on BC concentrations at the High Arctic site Villum Research Station was investigated. The effect was examined from March 2020, around when global lockdowns began, to June 2020, when the Arctic haze period ended and BC levels were once again low. Firstly, the Danish Eulerian Hemispheric Model (DEHM) was used to assess this impact on BC concentrations by adjusting global anthropogenic pollution emission inventories to simulate those observed during the lockdown period and comparing the results to a similar model run with standard emission inventories. Secondly, equivalent BC data from an aethalometer at Villum Research Station were analysed, comparing the concentrations during the lockdown period to both aethalometer data from previous years and DEHM results from the lockdown period. It was found that when adjusted DEHM emission inventories were introduced from the 1st of March, the model predicted a reduction in BC concentrations beginning on the 10th of March and reached a 10% reduction by the 1st of April. This reduction fluctuated around 10% until the end of the Arctic haze period. Aethalometer data did not show any significant change from previous years, and no concentration reduction could be concluded from its comparison with DEHM results. This is likely because the predicted reduction of 10% is smaller than both the inter-annual and intra-annual variability of measured BC concentrations at Villum. • DEHM model and aethalometer used to assess effect of lockdown on Villum BC levels. • DEHM model simulated a 10% reduction in BC at Villum during April–May 2020. • Similar reductions are expected throughout the Arctic region (between 7% and 11%). • The aethalometer showed no response to the lockdown due to inherent BC variability. [ABSTRACT FROM AUTHOR]

Gas flaring in the oil and gas industry has been identified as an important source of anthropogenic black carbon (BC) affecting the climate, particularly in the Arctic. Our study provides spatially-explicit estimates of BC emissions from flaring in Russia utilising state-of-the-art methodology for determining the emission factors. We utilised satellite time series of the flared gas volume from Visible Infrared Imaging Radiometer Suite (VIIRS) for the period 2012 to 2017, supplemented with information on the gas and oil field type. BC emissions at flaring locations were calculated based on field type-specific emission factors, taking into account different gas compositions in each field type. We estimate that the average annual BC emissions from flaring in Russia were 68.3 Gg/year, with the largest proportion stemming from oil fields (82%). We observed a decrease in the yearly emissions during the period 2012 to 2017 with regional differences in the trend. Our results highlight the importance of detailed information on gas composition and the stage of oil and gas separation of the flared gas to reduce uncertainties in the BC emission estimates. [Display omitted] • New estimate for black carbon emissions from flaring in Russia. • Enhanced temporal profiles of flared gas volume from VIIRS. • Oil and gas field-type specific emission factors developed. • Average BC emissions from 2012 to 2017 are estimated at 68.3 Gg/year. [ABSTRACT FROM AUTHOR]

Two months (Oct.–Nov. 2015) of online elemental carbon (EC) and organic carbon (OC) measurements were performed by two field OC/EC Sunset Laboratory analysers working in parallel with an 8-h time resolution at a subarctic remote station in Finland. During such a time resolution, thermal OC and EC concentrations were usually close to or below the recent limits of detection for the analyser. Thus, this work highlights the possible issues to consider during the online measurements of OC/EC analysers working at the threshold of their analytical possibilities. A detailed analysis of the data showed that even though the OC concentrations were always above the detection limit of the analyser, up to 70% of the given concentration was due to the dynamic blank (gaseous phase). The majority of the OC aerosol was present in the less volatile fractions that evolved during steps at 300–450 °C and 450–650 °C. The main bias at low EC concentrations originated from the automatically determined split point between OC and EC. The results from the RTCalc526 software often led to an early determination of the OC-EC split point, resulting in an overestimation of the EC concentrations. However, the comparison of the results was performed after processing the OC/EC raw data in the different RTCalc software versions 526 and 703. The results showed that the EC values from the newer version of the RTCalc703 software were more consistent with the equivalent black carbon (eBC) results from optical instruments (aethalometer and MAAP) measured in parallel in comparison with results from the older RTCalc526 software. Equivalent BC data from the laser attenuation measurement of the Sunset Lab. analyser also provided better agreement with the newer version of the RTCalc software (RTCalc703). Image 1 • A major part of the organic carbon (OC) was present in the less volatile fractions. • Up to 70% of the OC concentration was caused by a contribution of the dynamic blank (gaseous phase). • The elemental carbon (EC) results were overestimated in the earlier RTCalc526 evaluation software. • The updated RTCalc703 software provides reasonable results for very low EC concentrations. • The EC results are comparable to the parallel measurements of the equivalent black carbon. [ABSTRACT FROM AUTHOR]